Engine Cooling – GEN IV V8 Page 6B4–1

Page 6B4–1

Section 6B4

Engine Cooling – GEN IV V8

ATTENTION

Before performing any Service Operation or other procedure described in this Section, refer to

00 Warnings, Cautions and Notes for correct workshop practices with regard to safety and / or property

damage.

General Information ...............................................................................................................................3

General Description ...............................................................................................................................4

2.1

Radiator Assembly ................................................................................................................................................ 4

2.2

Cooling Fans .......................................................................................................................................................... 6

Overview................................................................................................................................................................. 6

Relays ................................................................................................................................................................ 6

Fan Motors ......................................................................................................................................................... 6

Cooling System...................................................................................................................................................... 7

Operation ........................................................................................................................................................... 8

2.3

Coolant Pump....................................................................................................................................................... 14

2.4

Thermostat ........................................................................................................................................................... 15

2.5

Radiator Cap......................................................................................................................................................... 16

2.6

Coolant Recovery Reservoir ............................................................................................................................... 17

2.7

Vapour Vent System ............................................................................................................................................ 18

2.8

Air Baffles and Ducts........................................................................................................................................... 19

2.9

Engine Coolant Temperature Sensor................................................................................................................. 21

Service Operations...............................................................................................................................22

3.1

Service Notes ....................................................................................................................................................... 22

Safety .................................................................................................................................................................... 22

Periodic Servicing................................................................................................................................................ 22

Environmental Issues.......................................................................................................................................... 23

3.2

Coolant Maintenance........................................................................................................................................... 24

Topping Up the Cooling System......................................................................................................................... 24

Testing Coolant Concentration........................................................................................................................... 25

Method 1 – Refractometer................................................................................................................................ 25

Method 2 – Hydrometer.................................................................................................................................... 27

3.3

Draining and Filling Cooling System ................................................................................................................. 29

Draining ................................................................................................................................................................ 29

Filling .................................................................................................................................................................... 30

3.4

Coolant Hoses...................................................................................................................................................... 32

3.5

Cleaning Cooling System.................................................................................................................................... 35

Cooling System Reverse Flush .......................................................................................................................... 35

Radiator............................................................................................................................................................ 35

Engine .............................................................................................................................................................. 36

Heater Hoses and Core.................................................................................................................................... 37

3.6

Engine Accessory Drive Belt Tension................................................................................................................ 39

3.7

Engine Accessory Drive Belt .............................................................................................................................. 40

Remove................................................................................................................................................................. 40

Inspect .................................................................................................................................................................. 40

Install .................................................................................................................................................................... 41

3.8

Pressure Testing.................................................................................................................................................. 42

Radiator Cap Pressure Testing........................................................................................................................... 42

Cooling System Pressure Testing...................................................................................................................... 43

Techline

Engine Cooling – GEN IV V8 Page 6B4–2

Page 6B4–2

3.9

Thermostat ........................................................................................................................................................... 45

Remove................................................................................................................................................................. 45

Test ....................................................................................................................................................................... 46

Disassemble......................................................................................................................................................... 46

Reassemble.......................................................................................................................................................... 47

Install .................................................................................................................................................................... 48

3.10

Coolant Recovery Reservoir ............................................................................................................................... 49

Remove................................................................................................................................................................. 49

Inspect .................................................................................................................................................................. 49

Install .................................................................................................................................................................... 50

3.11

Oil Pan Under-tray ............................................................................................................................................... 51

Remove................................................................................................................................................................. 51

Install .................................................................................................................................................................... 51

3.12

Air Baffles and Ducts........................................................................................................................................... 52

Remove................................................................................................................................................................. 52

Standard GEN V8 III Engine – View ‘C’............................................................................................................ 52

SS Models – View ‘D’....................................................................................................................................... 53

AWD Models (Wagon and Crew Cab) – View ‘E’ ............................................................................................. 53

Coupe Models – View ‘F’.................................................................................................................................. 53

Install .................................................................................................................................................................... 53

3.13

Coolant Pump....................................................................................................................................................... 54

Remove................................................................................................................................................................. 54

Disassemble......................................................................................................................................................... 56

Clean and Inspect ................................................................................................................................................ 57

Reassemble.......................................................................................................................................................... 57

Install .................................................................................................................................................................... 57

3.14

Cooling Fans and Shroud Assembly ................................................................................................................. 58

Remove................................................................................................................................................................. 58

Disassemble......................................................................................................................................................... 61

Reassemble.......................................................................................................................................................... 61

Install .................................................................................................................................................................... 61

3.15

Radiator ................................................................................................................................................................ 62

Remove................................................................................................................................................................. 62

Install .................................................................................................................................................................... 64

Radiator Repair Procedure.................................................................................................................................. 65

Repairable Leaks ............................................................................................................................................. 65

Repair Method.................................................................................................................................................. 66

Tube Blocking................................................................................................................................................... 66

Header Repair.................................................................................................................................................. 66

General Core Repair ........................................................................................................................................ 67

Transmission Oil Cooler Leak Test .................................................................................................................. 67

Transmission Oil Cooler Seal Replacement..................................................................................................... 67

3.16

Flexible Transmission Cooler Hose ................................................................................................................... 68

Replace ................................................................................................................................................................. 68

Engine Cooling System Diagnosis .....................................................................................................70

4.1

Poor Heater Operation......................................................................................................................................... 70

4.2

Leaking Cylinder Head Gasket ........................................................................................................................... 71

4.3

Question the Customer ....................................................................................................................................... 72

4.4

Diagnostic Chart .................................................................................................................................................. 73

4.5

Problems Not Requiring Disassembly of Cooling System............................................................................... 75

4.6

Problems Requiring Disassembly of Cooling System...................................................................................... 76

4.7

Black Light and Dye Leak Diagnosis Method.................................................................................................... 77

5 Specifications .......................................................................................................................................78

6 Torque Wrench Specifications............................................................................................................80

Special Tools ........................................................................................................................................81

Engine Cooling – GEN IV V8 Page 6B4–3

Page 6B4–3

1 General Information

The cooling system for MY 2006 WL Series v ehicles fitted with GEN IV V8 engines has been significantly modified. The

following list is a summary of new and modified compon ents:

• Revised radiator assembly (new fin and tube technology and spacing).

All WL Series vehicles with the GEN IV V8 engine, use a two stage cooli ng fan operation, wher e both fan motors will

operate either on low-speed (Stage 1) or high-speed (Stage 2).

All WL Series vehicles with the GEN IV V8 engine, use a co mmon CRF M using 400W cooling fan system. Each fan

motor is dual-speed and each has a different po wer rating – 180 and 220 Watt. Both fan motors fitted, operate either on

low-speed (Stage 1) or high-spee d (Stage 2).

Regardless of the system fitted, operation of the cooling fans is dependent on engine coolant temperature, vehicle

speed, A/C request (where fitted) and A/C system pressure. Refer to Section 6C4-1 Engine Management – GEN IV V8 –

General Information for further information.

The air conditioning system condenser is mounted to the front of the radiator and is located and sup ported by four clips

moulded into the front of the plastic radiator tanks. The lower clips lock the condenser in place and can be released by

hand to facilitate condens er removal.

The condenser, filter drier receiver, radiator and the fan motors / blades / shroud assembly can be removed and installed

individually from the vehicle. For removal and installation procedures relating to air conditioning components, refer to

Section 2C HVAC Climate Control (Man ual A/C) – Removal and Installation .

Engine Cooling – GEN IV V8 Page 6B4–4

Page 6B4–4

2 General Description

2.1 Radiator Assembly

When the vehicle is built, the air conditioning condenser, filter drier receiver, cooling fans, fan shroud and radiator are

installed into the engine bay as a pre-assembled unit. This unit is described as the radiat or assembly or as the

Condenser, Radiator and Fan Module (CRFM).

The radiator utilises an aluminium core and is of the cross-flow design. Plastic side tanks are attache d to the core by the

use of clinch tabs. The clinch tabs are forme d as part of the core assembly.

Pegs are attached to the lower frame and the upper area of each side tank. T hese pegs are used to support the radiator

in four rubber mounts. The assembly is hel d in position by two spring clips at the upper mounting locations.

A high temperature rubber seal is used to seal the mating surface between the core and each side tank. The seal(s)

must be replaced any time the side tank is removed from the core.

NOTE

The radiator core side tanks or transmission

oil cooler CANNOT be replaced separately. If

there is a fault with any of these components,

the radiator assembly must be replaced. Small

core repairs may be made, using an aluminised

silicon based liquid repair agent. Refer to

3.15 Radiator – Radiator R epair Procedure in this

Section.

For vehicles with automatic transmission, a transmission oil cooler is l ocated in the right-hand side radiator tank. The

cooler pipes from and to the transmission are connected to the oil cooler flexible hoses by means of quick connect

fittings.

When air conditioning is fitted, the air conditioning condens er is mounted to the front of the radiator and is located and

supported by four clips moulded into the front of the plastic radiator tanks. The lower clips lock the condenser in p lace

and can be released by hand to facilitate condenser removal. The air conditioning receiver drier also forms a part of the

complete assembly.

The cooling fan motors are each attached b y three screws to the one-piece plastic fan shroud. The fan shroud is

mounted to the rear of the radiator and is located and supported by four clips moulded into the rear of the plastic ra diator

tanks. The upper clips lock the fan shroud in place and can be released by hand to facilita t e fan shroud removal. The

shroud must be removed to facilitate fan motor and bl ade assembly removal.

Two harness connectors are mounted to the upper section of the fan shroud allowing the fan motor and blade

assemblies to be removed individually from the shroud. The fan motor and blade is balanced as an assembly. These two

components are serviced only as a unit and must not be separated.

For a comprehensive description of the different operating strategies and electrical wiring for the 400W system, refer to

2.2 Cooling Fans in this Section.

The shroud, fan assemblies and transmiss ion cooler hoses can be removed and installed individually from the vehicle.

For removal and installation procedures refer to 3.14 Cooling Fan and Shroud Assembly, 3.16 Flexible Transmission

Cooler Hose and 3.15 Radiator in this Section. F or remova l and installation procedures relati ng to the air conditioning

assemblies in the CRFM, refer to Section 2C HVAC Climate Control (Manu al A/C).

Engine Cooling – GEN IV V8 Page 6B4–5

Page 6B4–5

Figure 6B4 – 1

Legend

1 RHS Fan and Fan Motor Assembly

2 Fan Shroud

3 RHS Fan Retaining Screw (3 places)

4 LHS Fan Retaining Screw (3 places)

5 LHS Fan and Fan Motor Assembly

6 Upper Transmission Cooling Line and Seal

7 Lower Transmission Cooling Line and Seal

8 Upper Radiator Insulators (2 places)

9 Radiator

10 Lower Radiator Insulators (2 places)

11 Upper Condenser Mounting Clips (2 places)

12 Upper Condenser Mounting Clip Screws (2 places)

13 Lower Condenser Mounting Clips (2 places)

14 Lower Condenser Mounting Clip Screws (2 places)

15 Condenser

16 Filter Drier Receiver Mounting Bracket

17 Filter Drier Receiver Mounting Bracket Screw

18 Filter Drier Receiver

19 O-ring

20 Ambient Air Temperature Sensor Mounting Bracket

Engine Cooling – GEN IV V8 Page 6B4–6

Page 6B4–6

2.2 Cooling Fans

Overview

All GEN IV V8 vehicles are fitted with a high power cooling fan system consisting of two dual-speed fans, which operate

with a two-stage strategy as follows:

• Stage 1 – both fans operate at low speed.

• Stage 2 – both fans operate at high speed.

Relays

The engine coolin g fan relays are located in the fuse and

relay compartment under the hood.

Legend

1 Cooling Fan Relay 1 for low-speed fan operation.

2 Cooling Fan Relay 2 (in conjunction with Cooling Fan

Relay 1) for high-speed fan operation.

Figure 6B4 – 2

Fan Motors

Figure 6B4 – 3

Legend

1 Three-wire Harness 2 Armature Shaft 3 Drain Hole

Dimension applicable to small diameter fan blade Dimension applicable to large diameter fan blade

Engine Cooling – GEN IV V8 Page 6B4–7

Page 6B4–7

All fan motors are 12 Volt, dual-speed types. Accordingly, the internal con s truction of the fan motor consists of four

brushes and four permanent magnets. A three-wire pigtail harness is permanently attached to both motors and is

attached to the polypropylene fan shroud at two locations by integral clips moulded as part of the shroud . T he RHS motor

harness is connected directly to the engine h arness thro ugh a 6-pin connector. It also carries an additional 4-pin

connector that attaches to the LHS motor harness and en abl es individual removal of the LHS and R HS fan and motor

assemblies when necessary, refer to Figure 6B4 – 1. The two associated electrical connectors are attached to the

shroud by way of slide lock clips. The motor is attached to the polypropylene fan shroud by three bolts installed at the

threaded mounting flanges, which protrude symmetrically from the rear of the fan motor housing, refer to Figure 6B4 – 3.

Suppression capacitors locat ed at the fan motor brush holders are incorpo r ated. These suppression capacitors help

eliminate fan motor noise through the ra dio speakers. As these capacitors are not service d separately, the motor

assembly must be replaced should a problem occur with either capacitor.

The enclosed fan motor housing is constructed of yellow zinc coated steel. A drain hole is located in the bottom of the

housing to allow for breathing and dra ining of any moisture ingress.

Both fan motors rotate in an anticlockwise direction when vie wed from the fan motor side.

Both LHS and RHS fan and motor are balanced as a unit and fan blades must not be separ ated from their respective

motors. Fan motors and blades are serviced only as an assembled unit. However, it should be noted that the central nut

attaching the fan blade to the motor shaft has a left-hand thread.

Cooling System

The cooling system includes two, dual-speed, engine cooling fan motors, both of which, drive fans with five,

asymmetrical blades that are designed to reduce air noise. The larger, right fan is 342 mm in diameter and has a mot or

rated at 220 Watts, while the smaller, left fan is 293 mm in diameter with a motor power rating of 180 Watts.

The following outlines the ope ration of the cooling system, at block level, also showing what inputs the Engine Control

Module (ECM) requires.

Figure 6B4 – 4

With 12 volts applied and the fans mount ed to the radiator with a condenser fitted, the operatin g speeds are:

Stage 1 Stage 2

Small Fan 2,350 ± 150 rpm 2,750 ± 150 rpm

Large Fan 2,050 ± 150 rpm 2,300 ± 150 rpm

Engine Cooling – GEN IV V8 Page 6B4–8

Page 6B4–8

Figure 6B4 – 5

Legend

1 Fan Shroud

2 Radiator Drain Tap

3 Radiator

4 Fan Shroud Lower Support

5 Fan Shroud Upper Support / Locking Retainer

6 Small, Left Fan – 5 Blade, 293 mm Diameter

7 Small, Left Fan Motor – 180 Watt, Dual-speed

8 Left Fan Motor Harness Connector (3 terminal)

9 Left and Right Fan Motor Harness Connector (5 terminal)

10 Oil Cooler, Upper Line Connection (Auto. Trans. only)

11 Oil Cooler, Lower Line Connection (Auto. Trans. only)

12 Large, Right Fan – 5 Blade, 342 mm Diameter

13 Large, Right Fan Motor – 220 Watt, Dual-speed

Operation

The electrical circuitry for each of the cooling fans has two negative and one positive terminal to achieve the dual-speed

requirement. In addition, the current draw is directed throug h separate neg ative termin als at the joint connector (9) in

Figure 6B4 – 5 for each fan motor to reduce the he at burden on the electrical connectors. Figure 6B4 – 6 shows how

current flows through one negative motor terminal of each fan at low operating spee d. Current flows through both

negative terminals of each fan motor when operating at high speed.

The positive terminals are permanently connected to battery voltage, via fusible links F101 (large fan) and F107 (small

fan).

Stage 1 Fan Operation

The ECM determines when to enable Stage 1, based on inputs from the A/C request sign al, Engine Coolant

Temperature (ECT) sensor and the Vehicle Speed Sensor (VSS).

When the ECM determines that Stage 1 cooling fan operation is required it energises Engine Cooling Fan Relay 1 (R7)

by suppling a ground sign al on circuit 335 causing the relay to operate. Once Engine Cooling Fan R elay 1 is operated it

provides a ground for the fan motors low-speed negative terminals via circ uit 532. The engine coolin g fans then operate

at low speed (Stage 1).

Engine Cooling – GEN IV V8 Page 6B4–9

Page 6B4–9

Figure 6B4 – 6

Engine Cooling – GEN IV V8 Page 6B4–10

Page 6B4–10

Figure 6B4 – 7

Conditions for Stage 1 Fan Operation

1 The ECM switches ON Engine Cool Fan Rela y 1 (R7) when the following conditions have been met:

• Air conditioning request indicated (YES) and the vehicle speed is less than 30 km/h, or

• Air conditioning pressure is greater than 1,500 kPa, or

• Coolant temperature is greater than 108° C, or

• When a ECT sensor failure in conjunction with an Intake Air Temperature (IAT) sensor failure is detected by

the ECM. For additional information. Refer to Section 6C4-2 Engine Management – GEN IV V8 – Diagnos tics

• When the ignition switch is turned from on to off and the engine coolant temperature is ab ove 113° C, the

ECM will continue to energise Engine Cool Fan Relay 1 for four minutes.

Engine Cooling – GEN IV V8 Page 6B4–11

Page 6B4–11

2 The ECM switches OFF Engine Cool Fan Rel ay 1 when the following conditions have been met:

• Air conditioning request not indicated (NO) and the coolant temperature is less than 104° C, or

• Air conditioning request indic ated (YES) with pressure less than 1,170 kPa, vehicle spee d greater th an

50 km/h, and coolant temperature less than 108° C.

NOTE

The Stage 1 cooling fan operation has a

minimum run on time function of 30 seconds.

Stage 2 Fan Operation

When the ECM determines that Stage 2 cool ing fan operation is required. F igure 6B4 – 8 shows how the ECM energises

Engine Cooling Fan Relay 2 (R5) by suppling a ground signal on circuit 4 73 causing the relay to operate. Once Engine

Cooling Fan Relay 2 has operated, it provides a ground for the fan motors high-speed negative terminals (internally

connected to the second negative brush of each fan motor) via circuit 409. As the lo w-speed negative terminals are still

grounded through Engine Coo ling F an Relay 1 (R7), the engine cooli ng fans will operate at high speed (Stage 2).

Figure 6B4 – 8

Engine Cooling – GEN IV V8 Page 6B4–12

Page 6B4–12

Figure 6B4 – 9

Engine Cooling – GEN IV V8 Page 6B4–13

Page 6B4–13

Conditions for Stage 2 Fan Operation

1 The Engine Cool F an Relay 2 cooling fan relay will be turned ON if the Engine Cool Fan Relay 1 has been

energised for 1 second and th e following conditions have been met:

• Engine coolant temperature is above 1 13° C, or

• Air conditioning pressure is greater than 2,400 kPa.

NOTE

If the Stage 1 cooling fan fun ction is off when the

criteria for turning on the Stage 2 cooling fan

function are first met, the Stage 2 cooling fan

function will begin to operate 1 second after the

Stage 1 cooling fan function is switched on.

2 The ECM will turn the high-speed cooling fan function OFF when:

• The engine coolant temperature is less than 108.5° C, and

• Air conditioning request is not indicated (NO), or

• Air conditioning request is indicated (YES) and the press ure is less than 1,900 kPa.

NOTE

• The Stage 2 cooling fan operation has a

minimum run on time function of 30 seconds

after the ignition switch has been turned Off.

• The ECM (GEN IV) determines operation

of the two dual-speed engine-cooling fans

based on A/C request, A/C system pressure

(where fitted), engine coolant temperature

and vehicle speed signal inputs. For further

details of the engine cooling fan operation

and diagnosis of the system. Refer to

Section 6C4-2 Engi ne Management – GEN I V

V8 – Diagnostics.

Engine Cooling – GEN IV V8 Page 6B4–14

Page 6B4–14

2.3 Coolant Pump

The coolant pump (1) is mounted to the front of the

cylinder block by six bolts (2) and sealed with two

gaskets (3). The coolant pump is driven by the

crankshaft pulley (4) via a serpentine drive belt, turning

the pump pulley (5), bolted to the coolant pu mp. Coolant

passes through the engine from the coolant pump inlet

via the thermostat (6) and exits via the coolant outlet (7)

located at the top of the coolant pump housing.

Figure 6B4 – 10

Engine Cooling – GEN IV V8 Page 6B4–15

Page 6B4–15

2.4 Thermostat

A wax pellet type thermostat is used to provi de fast engine

warm up and to regulate the coolant temper ature by

controlling the coolant flow.

The wax pellet (1) located in the thermostat brass body (2)

expands when heated and contracts when cooled.

When the engine coolant is cold, the flow control valve (3)

prevents coolant flow (A) from the radiator to the engine.

With the wax pellet contracted, the bypass valve (4) is held

open and allo ws coolant (B) circulati ng within the engine to

flow over the thermostat assembly.

The coolant flow over the thermostat brass body heats-up

the wax pellet at the same rate as the temperature increase

in the engine.

Figure 6B4 – 11

When the coolant warms up, the wax pellet (1) expands

pushing the thermostat brass body base (2) against the

piston and pin (3) causing the brass body to move within the

thermostat assembly

As the thermostat brass body moves back, th e flow control

valve (4) attached to the thermostat brass body moves with

it and allows the coolant from the radiator (A) to flow into the

engine. At the same time, the bypass valve begins to close.

When the bypass valve is closed, a reduc ed flow of coolant

will continue to bypass via large crescent shaped bleed

holes located on the bypass valve. This prevents hydraulic

lock of the heater system and allows some engi ne bypass

coolant (B) to flow over the thermostat assembly.

The rate that the control valve opens is balan c ed between

the force exerted by the expanding wax and the combining

force exerted by the bypass valve spring a nd the flow

control spring.

This controlled coolant flow during cold start and initial

warming of the engine provides a controlled warming cycle

necessary to control exhaust emissions during the critical

warm-up period.

Figure 6B4 – 12

NOTE

For thermostat service procedure refer to

3.9 Thermostat in this Section.

Engine Cooling – GEN IV V8 Page 6B4–16

Page 6B4–16

2.5 Radiator Cap

The radiator pressure cap (1) fitted to the fille r neck (2) on

the right-hand side radiator tank causes the cooling system

to operate at above atmospheric pressure. The higher

pressure raises the boiling point of the cool ant, allowing the

engine to run at a higher tem perature and resulting in higher

efficiency of both the engine and the cooling s ystem. The

radiator cap contains a pressure valve (3) a nd a vacuum

valve (4). The pressure valve is hel d against its seat by a

spring (5), which determines the maxim um o perating

pressure of the cooling system (120 kPa for the GEN IV V8

engine).

Figure 6B4 – 13

The vacuum valve (4) is held against its seat by a light

spring (not illustrated) and opens during cool-down when

the pressure drops below atmospheric as a result of

contraction of the coolant. When the differenc e between

atmospheric and cooling syst em pressure becomes

sufficient to overcome the spring load, the vacuum valve

opens; then, under atmospheric pressure, coolant from the

overflow reservoir flows back into the cooling system in an

attempt to bring the cooling system pressure up to

atmospheric. In this way the radiator hoses are prevente d

from collapsing and the coolant is maintai ne d at the ide al

level within the radiator and engine.

Figure 6B4 – 14

Should the radiator pressure cap require

replacement, only fit the correct cap (w ith the

correct pressure-rating) for this engine. Refer

to the current release of Partfinder™ for this

information.

The cooling system is design ed to use a coolant, DEX-COOL® long-life coolant or equivalent to GM specification 6277M

(a mixture of ethylene glyc ol antifreeze and corrosion inhib itors and water), rather than plain water to maintain the

integrity of the cooling system, and to prevent oxidatio n occurring within the engine.

NOTE

Some MY 2006 VZ Series vehicle markets call for

DEX-COOL® long-life coolant and others for its

equivalent, known as Extended Life Anti-freeze

Coolant, conforming to GM specification 6277M.

If in doubt regarding the correct coolant to be

used, refer to the MY 2006 VZ Series Owner’s

Handbook.

Engine Cooling – GEN IV V8 Page 6B4–17

Page 6B4–17

2.6 Coolant Recovery Reservoir

The coolant recovery reservoir is located on the left-hand side front of the engine compartment, between the radiator

support panel and the air cle aner assembly. A small diameter hose connects the reservoir to the radiator overflow

connection.

As the engine temperature rises, the coolant is heated and expands. The coolant displaced by expansion flows from the

radiator into the reservoir. When the engi ne cools down, the process is reversed with coolant flo wing back into the

cooling system via the vacuum valve in the radiator cap.

The coolant level should be maintained between the

indicator arrows (A) on the reservoir’s dipstick, as shown in

Figure 6B4 – 15, when the engine is cold.

Figure 6B4 – 15

Engine Cooling – GEN IV V8 Page 6B4–18

Page 6B4–18

2.7 Vapour Vent System

Any vapour that develops in the engine or air trapped

when the cooling system is being filled is routed back to

the radiator. The vapour or air passes through a vent

tube (1) fastened to the front of the cylinder heads at two

places by double-ende d studs (2). The rear locations are

blocked-off by two vent covers (3) fastened to the rear of

cylinder heads at two places b y bolts (4). All four

locations are sealed by gaskets (5).

A small diameter hose connects the vent tube to the

radiator cap filler neck via a connectio n on the underside

of the throttle body.

Refer to Section 6A4 Engine Mechanical – GEN IV V8 for

further information on the vapour vent system.

Figure 6B4 – 16

Engine Cooling – GEN IV V8 Page 6B4–19

Page 6B4–19

2.8 Air Baffles and Ducts

Figure 6B4 – 17

Legend

1 Screws (2 places)

2 Lower Air Chute Baffle Extension

3 Lower Air Chute Baffle

4 Plastic Scrivet Fasteners (4 places)

5 Lower Air Chute Extension Duct

6 Plastic Fasteners (2 places)

7 Right-hand Side Air Chute

8 Left-hand Side Air Chute

A lower air chute baffle and side chutes are fitted to the front end of the vehicle to direct and promote airflow through the

radiator to provide maximum cooling. A lower air chute extension is fitted to SS pack vehicles to increase airflow through

the radiator core.

With reference to Figure 6B4 – 17, view ‘C’ shows the standard GEN IV V8 air chute baffle configuration, view ‘D’ shows

the GEN IV V8 ‘SS’ pack configuration.

The purpose of the lower air chute baffle is to create a low-pressure area behi nd the radiator whilst the vehicle is at

speed. This enables additional airflow through the radiator core to maintain the desired engine cooling.

The air baffle or chutes should only be removed for service work. If either the air b affle or chutes are damaged, this will

reduce the cooling system efficiency, and therefore they must be replaced.

Engine Cooling – GEN IV V8 Page 6B4–20

Page 6B4–20

An oil pan under-tray (1) also forms an integral part of the

air flow system around the GEN IV V8 engine and must

always be installed after removal for service operations,

such as engine oil draining and oil filter replacement.

NOTE

This under-tray is not designed as an oil pan

stone guard.

Figure 6B4 – 18

An upper radiator shroud (1) is fitted between the upper

radiator support panel and the radiator assembly to

minimise the recirculation of hot air from the rear of the

radiator back over the core and to direct cool incoming air

from the front of the vehicle through the radiator core. The

shroud is held in place by five plastic scrivets (2) and a

retaining clip (3).

Figure 6B4 – 19

Engine Cooling – GEN IV V8 Page 6B4–21

Page 6B4–21

2.9 Engine Coolant Temperature Sensor

An Engine Coolant Temperatur e (ECT) sensor (1) is

mounted in the front of the left-hand side cylinder h ea d.

The coolant temperature sen sor gen erates a signal, which is

used by the Engine Control Module (ECM) for GEN IV

engines, for calculation of the various Engine management

functions. This information is transmitted to other control

modules, e.g. Instruments for the temperature gauge

function, on the serial data bus.

Refer to Section 6C4-1 Engine Management – GEN IV V8 –

General Information for further information on the ECT

sensor.

Figure 6B4 – 20

Engine Cooling – GEN IV V8 Page 6B4–22

Page 6B4–22

3 Service Operations

3.1 Service Notes

Safety

• Do not remove the radiator pressure cap

when the engine is hot, even if the cooling

system requires filling. Sudden release of

cooling system pressure is very

dangerous and may result in the coolant

surging out and over the person removing

the cap leading to possible serious injury.

• The vehicle is fitted with twin electric

radiator cooling fans. When working

around the engine compartment, keep

clear of the fans as they may st art without

warning.

Before removing the radiator cap, all ow the engine to cool to ambient temperature (less than 50° C), place a shop rag

over the cap and slowly turn the cap anticlockwise to the detent position. Any residual pressure will be released into the

dam under the cap and thence to atmosphere through the coolant recovery reservoir. When it is clear that all coolin g

system pressure has been released the cap may be further turned anticlockwise to the stop and then removed.

Periodic Servicing

The cooling system requires little attention except for maintaining the coolant to the correct level in the recovery reservoir

and periodic servicing at the time or distance intervals as outlined in Section 0B Lubrication and Service.

Periodic servicing includ es:

1 Checking the coolant level. Refer to 3.3 Draining and Filling Cooling System in this Section.

2 Checking the coolant concentration. Refer to 3.2 Coolant Maintenance – Testing Coolant Concentration in this

Section.

3 Pressure test the cooling system and radiator cap. Refer to 3.8 Pressure Testing in this Section.

4 Check / tighten hose clamps and inspect all hoses. Refer to 3.4 Coolant Hoses in this Section. Replace hoses if

swollen or deteriorated.

Always wear protective safety glasses when

working with spring-type hose clamps. Failure

to do so may result in eye injury.

5 Clean out the cooling system, refer to 3.5 Cleaning Cooling System in this Section, and refill. Refer to

3.3 Draining and Filling Cooling System in this Section.

Engine Cooling – GEN IV V8 Page 6B4–23

Page 6B4–23

Environmental Issues

To reduce the impact on the environment and the maintenance cost, whenever the coolant is to be drained from the

engine, first check the service records to ascertain when the coolant was last changed. If more than six months’ life

remains before the next coolant change is due, proceed as follows:

1 Drain the coolant from the engine into a clean container with a capacity of at least 11 litres ensuring that the

coolant is not contaminated in the process.

2 Refill the cooling system with the drained coolant after repairs have been completed.

3 Top up as required, using a 50 / 50 mix of clean water and the recommended coolant, which is either DEX-COOL®

long-life coolant or its equivalent, known as extended life anti-freeze coolant conforming to GM specification

6277M. Refer to 3.2 Coolant Maintenance and 3.3 Draining and Filling Cooling System in this Section, for the

necessary procedures and further information.

Engine Cooling – GEN IV V8 Page 6B4–24

Page 6B4–24

3.2 Coolant Maintenance

The cooling system is design ed to use a coolant (a mixture of ethylene glyco l antifre eze with added corrosion inhibitors,

and water), rather than plain water. T he use of glycol also raises the boiling point and inc r eases the cooling system

efficiency. For this reason, it is of the utmost importance that the correct concentration level of ethylene glycol in the

cooling system is maintained.

Addition of plain water into the cooling system when 'topping-up' may dilute the coolant mixture to a point where the

antifreeze / anti-boil and corrosion inhibitor properties of eth ylene glycol become ineffective.

The coolant should comprise of a mixture 50% ethylene glycol antifreeze / inhibitor with 50% clear, clea n water.

Ethylene glycol conforming to the correct specificatio n is eith er named DEX-COOL® long-life coolant or its equivalent,

known as extended life anti-freeze coolant conforming to GM specification 6277M. Both are available i n a number of

different quantities. Check the current release of Partfinder ™ for specific details.

Do not mix different types of antifreeze or

corrosion inhibitors, as they may be

incompatible. If a different type ha s been u sed

in the cooling system, flush the system with

clean water, refer to 3.5 Cleaning Cooling

System in this Section and refill the cooling

system with the correct coolant. Refer to

3.3 Draining and Filling Cooling System in

this Section.

Topping Up the Cooling System

The coolant level must be maintain ed within the range

(A) between the marks on the coolant recovery reservoir

dipstick as shown in Figure 6B4 – 11 when the engine

cold.

Premixed coolant (50% DEX-COOL® long-life coolant or

equivalent to GM specification 6277M with 50% clean,

good quality water) may be added as necessary to

obtain the required level. Refer to 3.3 Draini ng and Filling

Cooling System in this Section.

Figure 6B4 – 21

Engine Cooling – GEN IV V8 Page 6B4–25

Page 6B4–25

Testing Coolant Concentration

To ensure the specified ethylene glycol concentration is maintaine d in the engine coolant, the coolant concentration must

be checked at the time or distance intervals outlined i n the MY 2006 VZ Series Owner’s Handbo ok or Service Booklet in

the glove box.

NOTE

• While a number of coolant concentration

measuring devices are available, the two

preferred types are as described.

• The procedures detailed, apply to either

coolant type used.

Method 1 – Refractometer

NOTE

• Coolant tester, Tool No. J 26568, automatically

compensates for temperature .

• Ensure that the eyepiece of the tester is free

of coolant before looking through it.

• Before each use, swing back the plastic cove r

at the slanted end of the coolant tester,

exposing the measuring window and the

bottom of the plastic cover. Carefull y wipe the

measuring window dry with a tissue or clean,

soft cloth. Close the plastic cover.

1 Check the calibration of the coolant tester as follows:

a Place a few drops of distilled water (between 21 – 29°C) onto the measuring window, then close the plastic

cover.

b Point the tester toward any light source, look into the eyepiece and check that the indicated reading is zero. If

not, then recalibrate the tester as detailed at the end of this Test Method, Calibrating the Tester.

2 Remove the upper radiator shroud (1) as fol lows:

a Using a fine, flat-blade screwdriver to prise the

centre pin of the scrivet (2) upward and remove

the scrivet, five places.

b Lift up the radiator shroud to disengage the

retaining clip (3) and remove the shroud.

Figure 6B4 – 22

Engine Cooling – GEN IV V8 Page 6B4–26

Page 6B4–26

3 Release the tip of the bulb pump from under the

refractometer body. It is not necessary to remove the

complete pump from the tool.

Refer to 3.1 Service Notes in this Section,

for important safety items.

4 Carefully remove the radiat or cap from the right-hand

side radiator tank.

5 Insert the tube of the pump into the coolant and then

press the bulb to obtain a sample.

Figure 6B4 – 23

6 Bend the tube around and insert the end into the cover plate ope ning.

7 Press the pump bulb to deposit a few drops of coolant onto the measuring surface. Do not open the plastic cover

when taking readings, as moisture evaporation will change the reading obtained.

8 Point the coolant tester toward any light source,

looking into the eyepiece.

a The coolant protection read ing is at the point

where the dividing line between the light and

dark, crosses the scale.

b The scale for ethylene glycol (bold arrow) is the

reference scale for either DEX-COOL® lon g-life

coolant or its equivalent, known as Extended

Life Anti-freeze Coolant conforming to GM

specification 6277M.

NOTE

The temperature scale is reversed from that of

a conventional thermometer. Below zero

readings are on the upper half of the scale.

9 A reading between – 30 and – 52° C (corresponding

to a coolant concentration between 45 – 60%), is

satisfactory for the GEN IV V8 engine cooling

system.

Figure 6B4 – 24

NOTE

If the reading is not clear, then properly clean

and dry the measuring surface, then conduct

another test. Also ensure that there is sufficient

fluid on the measuring prism.

10 If the reading shows that the concentration level of

the coolant is inadequate, refer to the Coolant

Concentration table to determine the amount of

coolant that needs to be added to the coolant

recovery reservoir.

11 Install radiator cap and upper radiator shroud.

12 Start and run the engine until normal operating

temperature is reached, to allow the added coolant to

be distributed throughout the engine cooling system.

Figure 6B4 – 25

Engine Cooling – GEN IV V8 Page 6B4–27

Page 6B4–27

Coolant Concentration

Litres Of Coolant To Be Added

Concentration

Reading % Automatic Transmission Manual Transmission

0 5.50 5.70

5 4.95 5.13

10 4.40 4.56

15 3.85 3.99

20 3.30 3.41

25 2.75 2.85

30 2.20 2.28

35 1.65 1.72

40 1.10 1.14

45 0.55 0.57

50 0.00 0.00

Calibrating the Tester

The coolant tester calibration is checked at manufacture. If however, the calibration check detailed in Step 1 of this

method shows that the instrument is not reading correctly, then conduct the following recalibration procedure:

1 Remove the sealant covering the adjustme nt screw on the underneath of the tester.

2 With a distilled water sample on the measur ing surface, carefully adjust the screw until a zero reading is obtained.

NOTE

DO NOT completely remove the screw.

3 After recalibration, reseal the screw with a small amount of silicone sealant.

Method 2 – Hydrometer

1 Allow engine to cool to ambient temperature (less than 50° C).

2 Remove the upper radiator shroud (1) as fol lows:

a Using a fine, flat-blade screwdriver to prise the

centre pin of the scrivet (2) upward and remove

the scrivet, five places.

b Lift up the radiator shroud to disengage the

retaining clip (3) and remove the shroud.

Figure 6B4 – 26

Engine Cooling – GEN IV V8 Page 6B4–28

Page 6B4–28

Refer to 3.1 Service Notes in this Section, for

important safety items.

3 Carefully remove the radiator cap fr om the right-hand side radiator tank.

4 While holding the rubber bulb squeezed, insert

nozzle of coolant tester hydrometer, Tool No. AU505

into coolant. Releasing the rubber b ulb will then draw

sufficient coolant into the tester to float hydrometer

bulb freely.

5 Hold tester at eye level and read scale on

hydrometer bulb at coolant level.

The readin g shows the percentage of ethylene glycol

antifreeze contained in th e engine coolant.

6 The hydrometer reading should show 50% if the

coolant concentration is correct.

• If a reading of less than 50% is achieved, the

cooling system requires topping up with either

DEX-COOL® long-life coola nt or its equiva lent,

known as extended life anti-freeze cool ant

conforming to GM specification 6277M.

• Refer to the Coolant Concentration table shown

for the previous method to determine how

much coolant additive of either type is re quired

to be added to the cooling system to bring the

coolant to the specified concentration.

7 Drain sufficient quantity of coolant from cooling

system to allow top-up with coolant additive, then

add the required amount of the correct additive.

Install coolant filler cap to the coolant outlet housing.

Figure 6B4 – 27

8 Install radiator cap and upper radiator shroud.

9 Start and run the engine until normal operating temperature is reached. This will allow the added coo lant to be

distributed throughout the engine cooling system.

Engine Cooling – GEN IV V8 Page 6B4–29

Page 6B4–29

3.3 Draining and Filling Cooling System

Draining

Refer to 3.1 Service Notes in this Section, for

important safety items.

1 Allow engine to cool to ambient temperature (less than 50°C).

2 Refer to Section 00 Warnings, Cautio ns and Notes before disconnecting the battery.

3 Disconnect the battery ground lead. Refer to Section 12A Battery.

4 Remove the upper radiator shroud (1) as fol lows:

a Using a fine, flat-blade screwdriver to prise the

centre pin of the scrivet (2) upward and remove

the scrivet, five places.

b Lift up the radiator shroud to disengage the

retaining clip (3) and remove the shroud.

5 Remove the oil pan under-tray. Refer to

3.11 Oil Pan Under-tray in this Section.

6 On AWD vehicles, remove the front bumper

fascia under-tray (where fitted). Refer to

Section 1D Bumper Bars.

Figure 6B4 – 28

Refer to 3.1 Service Notes in this Section, for

important safety items.

7 Carefully remove the radiator cap fr om the right-hand side radiator tank.

8 Drain the coolant from the system via the radiator dra in tap on the lower LHS of the radiator. Attach a suitable piece

of rubber tubing to the tap outlet to help direct the flow of the coolant into a suitable container (capacity at least

11 litres). Refer to 3.1 Service Notes, Environmental Issues in this Section.

Engine Cooling – GEN IV V8 Page 6B4–30

Page 6B4–30

Filling

During any service op eration that requires the cooling system to be partly or completely drained, the following

instructions must be followed when refilling the cooling s ystem, to ensure that all air is ble ed from system.

Refer to 3.1 Service Notes in this Section, for

important safety items.

1 Ensure that the drain tap at the bottom of the left-hand side radi ator tank is closed.

2 Ensure that all coolant hoses are correctly installed and firmly clamped.

Always wear eye protection when working

with spring-type hose clamps. Failure to do

so may result in eye injury.

3 If new coolant is required, make-up a mixture consisting of 50% DEX-COOL® long-life coolant or equivalent to GM

specification 6277M and 50% clean, good quality water. The quantity required will depend on whether t he cooling

system was completely drained, in which case approximately 11 litres will be required.

Do not mix different types of anti-freeze or

corrosion inhibitors, as they may be

incompatible. Always check which coolant is

to be added to the vehicle being serviced. If a

different type has been used, or has been

accidentally added, flush the system with

clean water. Refer to 3.5 Cleaning Cooling

System in this Section.

Engine Cooling – GEN IV V8 Page 6B4–31

Page 6B4–31

4 Fill the system at the radiator cap as much as possible

with the engine off.

5 If releasing the vehicle to the customer, fill the coolant

reservoir to about 20 mm over the full mark on the

dipstick, before the thermostat opens.

6 Reconnect battery ground lead. Refer to

Section 12A Battery.

7 Alternatively run the engin e and wait until the

thermostat opens.

8 Top up at the radiator filler neck after the thermostat

has opened.

9 Pressure test the cooling system. Refer to

3.8 Pressure Testing in this Section.

10 Check the level of coolant in the coolant recovery

reservoir and top-up as nec essary. Refer to

3.2 Coolant Maintenance – Topping-up Cooling

System in this Section.

11 Install the radiator cap.

12 Set the heater control to maximum, start and run the

engine until normal operating temperature is reached

to disperse the added coolant through the cooling

system.

13 Install the upper radiator shroud.

14 Install the oil pan under-tray. Refer to

3.11 Oil Pan Under-tray in this Section.

15 On AWD vehicles, install the front bumper fas c ia

under-tray (where fitted). Refer to

Section 1D Bumper Bars.

Figure 6B4 – 29

Figure 6B4 – 30

Engine Cooling – GEN IV V8 Page 6B4–32

Page 6B4–32

3.4 Coolant Hoses

LT Section No. – 01 – 160

The coolant hose layout is shown in the following illustrations.

NOTE

The engine cooling fans, fan motors and

shroud are not shown in Figure 6B4 – 31 and

Figure 6B4 – 32 to show the hose routing more

clearly.

NOTE

Ensure that hose connections are thoroughly

cleaned before installing a ny new hose.

Engine Cooling – GEN IV V8 Page 6B4–33

Page 6B4–33

Figure 6B4 – 31

Legend

1 Hose – Heater, to Engine

2 Hose – Radiator Lower

3 Radiator

4 Hose – Vapour Vent Tube, Throttle Body to Radiator

5 Hose – Radiator Upper

6 Hose – Radiator to Coolant Recovery Reservoir

7 Housing – Thermostat

8 Hose – Heater, from Engine

Engine Cooling – GEN IV V8 Page 6B4–34

Page 6B4–34

Figure 6B4 – 32

Legend

1 Water Valve

2 Water Valve Actuator

3 Heater Hose – To Cabin

4 Heater Hose – From Cabin

5 Vacuum Hose (2 piece) – HVAC Supply

6 Check Valve

7 Vacuum Hose – To Inlet Manifold

8 Heater Hose – To Engine

9 Heater Hose – From Engine

10 Vacuum Hose – To Water Valve Vacuum Switch

11 Hose Clamps – Heater Core (2 places)

12 Vacuum Hose – To Water Valve Actuator

13 Brake Lines

14 Hose Clamps – Water Valve (4 places)

15 Wheel House – RHS

16 Mounting Clip – Water Valve

17 Heater Hose Clamps – Engine (2 places)

Engine Cooling – GEN IV V8 Page 6B4–35

Page 6B4–35

3.5 Cleaning Cooling System

NOTE

• Before carrying out reverse flushing

procedures, it is recommended that a

cleaning solution be use d to loosen scale and

corrosion. Use an approved radiator cleaner

following the instructions on the container

label.

• This operation should only be carried out

when the engine and radiator are at ambient

temperature.

• When using specialised cooling system

flushing equipment, conn ect the equipment as

recommended by the manufacturer.

Cooling System Reverse Flush

Radiator

1 Drain the cooling system. Refer to 3.3 Draining an d Filling Cooling System – Draining in this Section.

Always wear eye protection when working

with spring-type hose clamps. Failure to do

so may result in eye injury.

2 Remove the upper radiator hose (1) from the coolant

pump outlet.

3 Remove the engine coolant vapour ve nt hose (2) from

tube connection at the base of the throttle body and

temporarily plug the end of the hose.

Figure 6B4 – 33

Engine Cooling – GEN IV V8 Page 6B4–36

Page 6B4–36

4 Remove the lower radiator hose (1) from the

thermostat housing (2).

5 Attach a lead-away hose to the open end of the upper

radiator hose.

6 Attach a suitable piece of hose or ada ptor between the

flushing gun and the open end of the lower radiator

hose.

7 Connect and operate the flus hing equipment as

recommended by the manufacturer.

Apply air pressure gradually and not in

excess of 120 kPa, otherwise radiator

damage will result.

Figure 6B4 – 34

8 Continue flushing until the water from the lead-away hose runs clean and clear.

9 Unplug the end of the vapour vent hose and continue flushing unti l the water from the vent hose runs clear.

10 Remove the coolant recovery reservoir, flush it out with clean water and install. Refer to 3.10 Coolant Recovery

Reservoir in this Section.

11 Install all disconnected hoses, ensuring that they are correctly positioned and secur ely clamped.

12 Install the cooling system. Refer to 3.3 Draining and Filling Cooling System – Filling in this Section.

13 Pressure test the cooling system. Refer to 3.8 Pressure Testing in this Section.

Engine

1 Drain the cooling system. Refer to 3.3 Draining an d Filling Cooling System – Draining in this Section.

Always wear eye protection when working

with spring-type hose clamps. Failure to do

so may result in eye injury.

2 Remove the upper and lo wer radiator hoses from the coolant pump outlet and thermostat connections. Refer to

Figure 6B4 – 33 and Figure 6B4 – 34.

3 Remove the engine coolant vapour ve nt hose (1) from

radiator connection (2) and te mporaril y plug the end of

the hose.

4 Remove the thermostat housing and thermo stat from

the coolant pump. Refer to 3.9 Thermostat in this

Section.

5 Remove the thermostat from the thermostat housing

and install the housing to the coolant pump. Refer to

3.9 Thermostat in this Section.

Figure 6B4 – 35

Engine Cooling – GEN IV V8 Page 6B4–37

Page 6B4–37

Always wear eye protection when working

with spring-type hose clamps. Failure to do

so may result in eye injury.

6 Remove both heater hoses (1) and (2) from their

connections at the coolant pump, noting which hose

was connected to which connection. Seal the pump

connections by looping the co olant pump heater inlet

connection to the outlet connection using a suitable

piece of hose and two hose clamps.

7 Install a lead-away hose to the thermostat housing and

a length of suitable hose between the coolant pump

outlet fitting and the flushing equipment.

Figure 6B4 – 36

7 Connect and operate the flus hing equipment as recommended b y the manufacturer.

8 Continue flushing until the water from the lead-away hose runs clear.

9 Unplug the end of the vapour vent hose and continue flushing unti l the water from the vent hose runs clear.

10 Install the thermostat. Refer to 3.9 Thermostat in this Section.

11 Install all disconnected hoses, ensuring that they are correctly positioned and secur ely clamped.

12 Fill the cooling system. Refer to 3.3 Draining and Filling Cooling System – Filling in this Section.

13 Pressure-test the cooling system. Refer to 3.8 Pressure Testing in this Section.

Heater Hoses and Core

1 Drain the cooling system. Refer to 3.3 Draining an d Filling Cooling System – Draining in this Section.

Always wear eye protection when working

with spring-type hose clamps. Failure to do

so may result in eye injury.

2 Remove both heater hoses (1) and (2) from their

connections at the coolant pump, noting which hose

was connected to which connection.

3 Direct the hose (1) that was connected to the cool ant

pump’s rear-most connection into a suita bl e container.

4 Attach the hose (2) from the front connection to the

flushing gun.

5 Cycle the heater switch to ensure that the water valve

is open.

Figure 6B4 – 37

6 Connect and operate the flus hing equipment as recommended b y the manufacturer.

Engine Cooling – GEN IV V8 Page 6B4–38

Page 6B4–38

Apply air pressure gradually and not in

excess of 110 kPa, otherwise heater core

damage will result.

7 Install all disconnected hoses, ensuring that they are correctly positioned and securely clamped.

NOTE

For heater hose routing, refer to Figure 6B4 – 32.

8 Fill the cooling system. Refer to 3.3 Draining and Filling Cooling System, Filling in this Sect ion.

9 Pressure test the cooling system. Refer to 3.8 Pressure Testing in this Section.

Engine Cooling – GEN IV V8 Page 6B4–39

Page 6B4–39

3.6 Engine Accessory Drive Belt Tension

Drive belt tension is provided b y a tensioner assembly (1).

The tensioner is an idler pulley mounted on a

spring-loaded arm that maintains the drive belt (2) at the

correct tension, without imposing undue loads on the

various components.

Figure 6B4 – 38

Drive belt tension is within the prescribed lim its if the

indicator (bold arro w) on the tensioner is between points

‘A’ and ‘B’ on the tensioner bracket.

If replacement is indicated. Refer to 3.7 Engine Accessory

Drive Belt in this Section.

Figure 6B4 – 39

Engine Cooling – GEN IV V8 Page 6B4–40

Page 6B4–40

3.7 Engine Accessory Drive Belt

LT Section No. – 01 – 003

Remove

1 Using a 15 mm ring spanner, rotate the en gine

accessory drive belt tensioner (1) in the direction

indicated, to reduce belt tension.

2 While holding the tensi on er in the reduced tension

position, remove the accessory drive belt from the

engine, taking note of the belt routing.

Figure 6B4 – 40

Inspect

The four views in Figure 6B4 – 41 show the various stages of drive belt wear, to assist in belt replacement decisions.

NOTE

Condition of the belt ribs can be better assessed

if the belt is wrapped over the coolant pump drive

pulley.

Engine Cooling – GEN IV V8 Page 6B4–41

Page 6B4–41

Figure 6B4 – 41

Legend

A New Belt: No cracks or chunks.

B Moderately Used Belt: Few cracks, with some wear on the ribs and in the grooves. Belt replacement not required.

C Severely Used Belt: Several cracks per 30 mm. Should be replaced before chunking occurs

D Failed Belt: Separation of rib material from backing (chunking). Belt must be replaced immediately.

Install

Hold the tensioner in the unloaded position (arrow) with a

15 mm ring spanner, install the engine accessory drive

belt, routing in the same manner as noted on remova l

and as shown.

Figure 6B4 – 42

Engine Cooling – GEN IV V8 Page 6B4–42

Page 6B4–42

3.8 Pressure Testing

Radiator Cap Pressure Testing

Refer to 3.1 Service Notes in this Section, for

important safety items.

1 Allow engine to cool to ambient temperature (less than 50° C), then remove radiator cap.

2 Inspect and clean both sides (1) of radiator cap

gasket with a wet cloth.

NOTE

Use only water to wet cleaning cloth.

Figure 6B4 – 43

3 Lift centre vacuum valve. Clean and inspect the

gasket (1) and sealing surface of the under

valve (2).

Figure 6B4 – 44

Engine Cooling – GEN IV V8 Page 6B4–43

Page 6B4–43

4 Attach radiator cap (1) to a commercially available

cooling system pressure tester (2).

5 Slowly pressurise the cap us ing the pressure tester

hand pump, noting the point a t which the cap

unloads.

6 The cap is serviceable if it unloads sl ightly above a

pressure of 125 kPa and holds pressure above

95 kPa. Should the cap fail to reach or hold the

specified pressures, install a new pressure cap.

Figure 6B4 – 45

7 Prior to installing the radiator cap ensure that the

radiator filler neck cap seating surface (1) is clean

and free from obstruction. Refer to Figure 6B4 – 46

Figure 6B4 – 46

Cooling System Pressure Testing

Refer to 3.1 Service Notes in this Section, for

important safety items.

1 Allow the engine to cool to ambient temperature (less than 50° C), then carefully remove the radiator cap.

2 Ensure that the coolant level is correct.

Engine Cooling – GEN IV V8 Page 6B4–44

Page 6B4–44

3 Connect a commerciall y available cooling system

pressure tester (1) to radiator filler neck by using the

hose supplied (2) or other arrangem ent and using

compressed air, blow dry any spilled coolant around

radiator filler neck. Pressurise cooling system to not

more than 120 kPa and check for leaks at the

following points:

• All hoses and hose connectio ns.

• Radiator seams and core.

• Corroded or faulty engine core plugs.

• Coolant pump and gaskets and O-ring sea ls.

• Check engine oil dipstick for evid ence of

engine oil contamination with coolant.

• Radiator drain tap and bleed screw.

• Vehicle heating system (e.g. heater cor e an d

water valve). Figure 6B4 – 47

NOTE

For heater component Removal and Installation,

refer to Section 2C HVAC Climate Control

(Manual A/C) – Removal and Install ation.

4 If pressure will not hold, there is a leak in the cooling system . Repair as required.

NOTE

If visible loss of coolant is not evident from

pressure testing, then the use of a dye and black

light, may be necessary. Refer to 4.7 Black Light

and Dye Leak Diagnos is Method in this Section.

Engine Cooling – GEN IV V8 Page 6B4–45

Page 6B4–45

3.9 Thermostat

LT Section No. – 00 – 350

Remove

Refer to 3.1 Service Notes in this Section, for

important safety items.

1 Allow engine to cool to ambient temperature (less than 50° C), then remove radiator cap.

2 Drain the engine coolant into a suitable container. Refer to 3.3 Draining and Fillin g Cooling System in this Section.

Always wear protective safety glasses when

Disconnect radiato r hose from coolant inlet at

the thermostat housing. working with spring

type hose clamps. Failure to do so could

result in eye injury.

3 Disconnect radiator hose from coolant inlet at the

thermostat housing.

Figure 6B4 – 48

4 Remove thermostat housing bolts (1), and then

remove the housing (2), thermostat and O-ring seal

from the coolant pump.

Figure 6B4 – 49

Engine Cooling – GEN IV V8 Page 6B4–46

Page 6B4–46

Test

5 Suspend thermostat (1) and a suitable thermometer

(2) in a container of 50 / 50 extended life anti-freeze

coolant (conforming to GM6277M) and water.

NOTE

Neither the thermostat nor thermometer should

rest on the bottom of the container because of

uneven concentration of heat at this point when

the container is heated.

6 Heat container until thermostat begins to open. Agitate

solution to ensure uniform temperature. Note

temperature and ensure t hermostat opens within

specified temperature range.

7 Continue heating the solution until the thermostat is

fully open. Again agitate the solution and take note of

the temperature

8 Install a new thermostat if it does not meet the

specified temperatures.

Thermostat Specifications

Opening Temperature................................. 86 ± 1.5° C

Fully Open Temperature .................................... 100° C

Figure 6B4 – 50

Disassemble

NOTE

Only dismantle the thermostat if a reverse

flushing operation of the cylinder block is to be

carried out. If testing shows that replacement is

required, the thermostat and housing are only

serviced as a complete assembly.

1 Secure the thermostat housing by gripping in a vice fitted with soft jaws.

Always wear protective safety glasses to

avoid potential eye injury.

Engine Cooling – GEN IV V8 Page 6B4–47

Page 6B4–47

2 While compressing the springs with one hand, rotate

the retaining bar from the housing lugs and release.

Figure 6B4 – 51

3 Careful lay all parts out in ord er, for ease of

reassembly.

Legend

1 Bypass Valve

2 Bypass Valve Spring

3 Thermostat Closing Spring

4 Wax Pellet and Valve Assembly

5 Thermostat Housing

Figure 6B4 – 52

Reassemble

Reassembly is the reverse of disassembly procedures, except that the valve seat in the thermostat housing must be

checked for corrosion, scratches or other damage a nd the valve-seating surface wiped with a clean rag.

Engine Cooling – GEN IV V8 Page 6B4–48

Page 6B4–48

Install

1 Shake the thermostat assembly to ensure that the

air bleed check ball (1) in the housing is free and not

jammed.

2 Thoroughly clean the coolant pump to thermostat

housing sealing surfaces, taking care not to scratch

any machined alloy surfaces.

3 Install the thermostat assembly, with a new O-

ring (2), fitted to the coolant pump housing (3).

4 Install the thermostat housing to coolant pump

housing attaching bolts and tighten to the correct

torque specification.

Thermostat housing to coolant pump bolt

torque specification...........................................14 Nm

Figure 6B4 – 53

Always wear protective safety glasses when

working with spring type hose clamps. Failure

to do so could result in eye injury.

5 Install the radiator hose and cl amp to the thermostat housing.

6 Refill cooling system. Refer to 3.3 Draining and Filling Cooling System in this Section.

7 Check for cooling system leaks. Refer to 3.8 Pressure Testing in this Section.

Engine Cooling – GEN IV V8 Page 6B4–49

Page 6B4–49

3.10 Coolant Recovery Reservoir

LT Section No. – 01 – 140

Remove

1 Remove the coolant recovery hose from the radiator filler neck, and then remove the hose from the fan shroud and

MAF air intake housing ret aining clips.

2 Raise front of vehicle and support on safet y stands. Refer to Section 0A General Information for the location of

jacking and support points.

3 Remove the scrivet fastener attaching the wheelhous e liner to the coolant recovery reservoir.

4 Remove reservoir assembly attaching screws, and remove reservoir assembl y from under the vehicle.

Figure 6B4 – 54

Legend

1 Screw (3 places)

2 Reservoir 3 Coolant Dipstick

4 Console Front Panel 5 Scrivet Fastener

6 Wheelhouse Liner

Inspect

1 Drain contents from reservoir assembly.

Always wear protective safety glasses to

avoid potential eye injury.

2 Clean reservoir assembly with water and dry, using compressed air.

3 Check reservoir and assembly for damage, for example abrasions, cracks or distortion. Re place if required.

Engine Cooling – GEN IV V8 Page 6B4–50

Page 6B4–50

Install

Installation of the reservoir assembly is the r everse of removal procedures, noting the foll owing points:

1 For ease of access, it may be necessary to remove the upper radiator shroud.

2 Refill cooling recover y res ervoir and cooling s ystem with the correct concentration of coolant. Refer to

3.3 Draining and Filling Co oling System in this Section.

3 Check coolant recovery system for leaks.

Engine Cooling – GEN IV V8 Page 6B4–51

Page 6B4–51

3.11 Oil Pan Under-tray

Remove

1 Raise front of vehicle and support on safet y stands. Refer to Section 0A General Information for the location of

jacking and support points.

2 Remove the four bolts (1) securing the under -tray (2) to the crossmember and remove tray from vehicle.

Install

1 While holding the under-tray up to the crossmember

with one hand, install all four securi ng bolts.

2 Tighten all four bolts to the correct torque

specification. DO NOT OVER TIGHTEN THE

BOLTS.

Oil pan under-tray bolt

torque specification...........................................30 Nm

Figure 6B4 – 55

Engine Cooling – GEN IV V8 Page 6B4–52

Page 6B4–52

3.12 Air Baffles and Ducts

Figure 6B4 – 56

Remove

1 Raise front of vehicle and support on safet y stands. Refer to Section 0A General Information for the location of

jacking and support points.

2 Remove the oil pan under-tray. Refer 3.11 Oil Pan Under-tray in this Section.

Standard GEN V8 III Engine – View ‘C’

a Remove the two screws (1) securing the rear of the lower air chute baffle extension (2), lower the rear of the

lower air chute baffle extension, slide the baffle rearward to disengage from the lower front air chute baffle

(3), then remove from the vehicle.

b Remove the four scrivet fasteners (4) securing the lower front air chute baffle to the crossmember a nd

remove lower front air chute baffle from the vehicle.

Engine Cooling – GEN IV V8 Page 6B4–53

Page 6B4–53

SS Models – View ‘D’

a Remove the front bumper bar. Refer to Section 1D Bumper Bars.

NOTE

While the air duct can be removed without first

removing the bumper bar, excessive distortion of

the duct is required, both on removal and

installation. Also the installation of the two upper

scrivets is extremely difficult.

b Remove the four scrivet fasteners (4) securing both the lower front air chute baffle (3) and the air chute

extension duct (5) to the front suspension crossmember, then remove the lower front air chute baffle from the

vehicle.

c Remove the two fasteners (6) securing the air chute extension duct, to the front upper panel assembl y, then

remove the duct from the vehicle.

AWD Models (Wagon and Crew Cab) – View ‘E’

a Remove the front bumper bar fascia and und er-tray. Refer to Section 1D Bumper Bars.

b Remove the two lower scrivet fasteners (4) securing the air chute e xtension duct (5) to the radiator support

crossmember.

c Remove the two upper scrivet fasteners secu ring the air chute extension duct to the front upper pan el

assembly, and then remove the air chute ext ension duct from the vehicle.

Coupe Models – View ‘F’

a Remove the front bumper bar fascia. Refer to Section 1D Bumper Bars.

b Remove the four scrivet fasteners (4) securing both the lower front air chute baffle (3) and the air chute

extension duct (5) to the front suspension crossmember, then remove the lower front air chute baffle from the

vehicle.

c Remove the two fasteners (6) securing the air chute extension duct (5), to the front upper panel ass embly,

then remove the duct from the vehicle.

Install

Installation is the reverse to removal proced ures.

Do not over tighten any of the fasteners.

Engine Cooling – GEN IV V8 Page 6B4–54

Page 6B4–54

3.13 Coolant Pump

LT Section No. – 00 – 325

Remove

NOTE

Apart from the rear cover, O-ring and thermostat

assembly, the coolant pump is not serviceable

and if found to be faulty must be replaced as an

assembly.

1 Refer to Section 00 Warnings, Cautio ns and Notes before disconnecting the battery.

2 Disconnect the battery ground lead. Refer to Section 12A Battery.

3 Remove the upper radiator shroud (1) as fol lows:

a Using a fine, flat-blade screwdriver to prise the

centre pin of the scrivet (2) upward and

remove the scrivet, five places.

b Lift up the radiator shroud to disengage the

retaining clip (3) and remove the shroud.

Refer to 3.1 Service Notes in this Section,

for important safety items.

4 Allow engine to cool to ambient temperature (less

than 50°C), then slowly remove radiator cap from

the radiator.

Figure 6B4 – 57

5 Using a 15 mm ring spanner to move the belt

tensioner (1) in the clockwise direction indicated,

remove the engine accessor y drive belt (2). Refer to

3.7 Engine Accessory Drive Belt in this Section.

Figure 6B4 – 58

6 Drain engine coolant. Refer to 3.3 Draining and Filling Cooling System in this Section.

Engine Cooling – GEN IV V8 Page 6B4–55

Page 6B4–55

Always wear protective safety glasses when

working with spring type hose clamps. Failure

to do so could result in eye injury.

7 Disconnect both heater hoses, the outlet and inlet

hoses from the coolant pump.

Figure 6B4 – 59

8 Remove the two bolts (1) securing the drive belt

tensioner (2) to the coolant pump housing and set

the tensioner to one side.

Figure 6B4 – 60

Engine Cooling – GEN IV V8 Page 6B4–56

Page 6B4–56

9 Loosen, then remove the six bolts (1) securing the

coolant pump (2) to the cylinder block.

10 If necessary, use a soft-faced hammer to lightly tap

coolant pump housing (2) to dislodge it from the

cylinder block.

11 Remove coolant pump gaske ts (3) and discard.

Figure 6B4 – 61

Disassemble

NOTE

Apart from the service operations described here,

there are no ot her serviceable parts in the coolant

pump assembly and if required, then the

assembly must be replaced as a complete unit.

1 If required, remove the five bolts (1) securing the rear

cover (2) to the coolant pump (3). Tap with a

soft-faced hammer to dislodge the cover from the

pump body.

2 Remove the sealing O-ring (4) from the coola nt pump

body.

3 For thermostat remove, test and install procedures.

Refer to 3.9 Thermostat in this Section.

Figure 6B4 – 62

Engine Cooling – GEN IV V8 Page 6B4–57

Page 6B4–57

Clean and Inspect

1 Remove the old gasket and any gasket material from the coolant pump se aling surfaces and cylinder bl ock, taking

care not to scratch the machined surfaces.

2 Clean all dirt and debris from the coolant pump housing.

3 Inspect the coolant pump for the following:

• Gasket surfaces for excessive scratches or gouging.

• Hose sealing surfaces for scratches, gouging or corrosion.

• Restrictions, corrosion or evidence of cavitation within the internal coolant passages or on the pump impeller.

• Excessive side-to-side play in the pulley shaft.

• A loose belt pulley or a pulle y with e xcess ive wear or scoring on the belt tracking area.

• Evidence of coolant leakage at the coolant outlet housing or rear cover gasket (if these parts have not been

removed).

• Leakage at the coolant pump vent hol e. A stain around the vent hole is ac ceptable. If leakage occurs

(dripping) with the engine running and the cooling system pressurised, replace the coolant pump.

Reassemble

1 Install a new O-ring seal to the cleaned groo ve in the pump housing, then install the cover and retaining bolts.

2 Gradually tighten every second bolt until the correct torque specification is reached.

Coolant pump rear cover

bolt torque specification........................................ 14 Nm

Install

Installation is the reverse to removal except for the follo wing items:

1 Ensure that the coolant pump and cylinder block surfaces are clean and dry.

2 Using two bolts on each side a s guides install new gaskets over them and install the coolant pump to the c ylinder

block.

3 Install remaining bolts and tighten to t he correct torque specification in two stages.

Coolant pump to cylinder

block bolt torque specification:

Stage 1: ................................................................15 Nm

Stage 2: ................................................................25 Nm

4 Install the engine accessory dr ive belt tensioner and attaching bolts, tightening to the correct torque specification.

Engine accessory drive belt tensioner

bolt torque specification........................................ 50 Nm

Always wear protective safety glasses when

working with spring type hose clamps. Failure

to do so could result in eye injury.

5 Install all removed radiator hoses and clamps.

6 Install the engine accessory dr ive belt. Refer 3.7 Engine Accessory Drive Belt in this Section.

7 Refill cooling system. Refer to 3.3 Draining and Filling Cooli ng System in this Section.

8 Check for cooling system leaks. Refer to 3.8 Pressure Testing in this Section.

Engine Cooling – GEN IV V8 Page 6B4–58

Page 6B4–58

3.14 Cooling Fans and Shroud Assembly

LT Section No. – 01 – 105

Remove

1 Allow the engine to cool to ambient temperature (less than 50° C).

2 Refer to Section 00 Warnings, Cautio ns and Notes before disconnecting the battery.

3 Disconnect the battery ground lead. Refer to Section 12A Battery.

4 Remove the upper radiator shroud (1) as fol lows:

a Using a fine, flat-blade screwdriver to prise the

centre pin of the scrivet (2) upward and remove

the scrivet, five places.

b Lift up the radiator shroud to disengage the

retaining clip (3) and remove the shroud.

Figure 6B4 – 63

5 Remove the intake duct and Mass Air F low (MAF) as

an assembly. Refer to Section 6A4 Engine Mechanical

– GEN IV V8.

Figure 6B4 – 64

Engine Cooling – GEN IV V8 Page 6B4–59

Page 6B4–59

6 Remove the coolant recovery hoses from the fan

shroud retaining clips (1).

7 Depress tang on main wiring harness to cooling fan

motor wiring harness connector and separ ate

connector (2).

Figure 6B4 – 65

8 Release the upper automatic transmissi on cooling

pipe (1) (if fitted) from the integral clip (2) on the fan

shroud.

Figure 6B4 – 66

9 While holding the shroud locking tang in the r elease

position, lift the shroud and fan assembly upwards.

Repeat for the opposite side.

Figure 6B4 – 67

Engine Cooling – GEN IV V8 Page 6B4–60

Page 6B4–60

When removing, transporting or installing the

fan assembly, do not grasp the assembly by

the fan rings (1) as this may bend the fan

motor shafts and cause fan vibrations

Figure 6B4 – 68

When handling the fan assembly, always hold

the assembly at the fan shroud (1) or fan

motor mounting struts (2).

Figure 6B4 – 69

Engine Cooling – GEN IV V8 Page 6B4–61

Page 6B4–61

10 Lift the shroud and fan assembly clear from the engine

bay, grasping the motor mounting struts.

Figure 6B4 – 70

Disassemble

1 Remove cooling fan and shro ud assembly as

previously described.

NOTE

Neither fan is to be separated from its fan

motor. The assembly is carefully balanced

during manufacture and duplicating this

balance on reassembly is not possible.

2 Remove the motor assembly wiring harness (1) from

the integral clips that form a part of the shroud (2).

3 Separate the intermediate wiring harness

connector (3).

4 Remove screws (4) attaching the motor assembly to

the shroud, then remove each motor, fan and wiring

assembly (5) from the shroud.

Figure 6B4 – 71

Reassemble

Reassembly is the reverse of disass embly procedures, noting t he following points:

1 Tighten motor to shroud attaching screws to the correct torque specification. Do not over-tighten.

Fan motor to shroud screw

torque specification.................................................5 Nm

2 Ensure that all wiring is routed correctly and secured by the integra l shroud clips.

Install

Installation of the cooling fan and shroud assembly is the reverse of removal procedures, noting the following points:

1 Ensure that fan and shroud assembly to radiator attaching clips are all fully engaged and that the two locking tangs

on the upper clips secure the shroud correctly.

2 Ensure that the top automatic transmission cooling pipe (if fitted) is installed to the shroud clip.

3 Check cooling fan operation. Refer to Section 6C4-2 Engine Mana gement – GEN IV V8 – Diagnostics. Also check

for the correct cooling fan rotational direction.

Engine Cooling – GEN IV V8 Page 6B4–62

Page 6B4–62

3.15 Radiator

LT Section No. – 01 – 105

Remove

1 Allow the engine to cool to ambient temperature (less than 50° C).

2 Refer to Section 00 Warnings, Cautio ns and Notes before disconnecting the battery.

3 Disconnect the battery ground lead. Refer to Section 12A Battery.

4 Remove the radiator cooling fans and shroud assembly. Refer to 3.14 Cooling Fans and Shroud Assembly in this

Section.

5 Draining the coolant from the system. Refer to 3.3 Draining and Filling Coo ling System in this Section.

Always wear protective safety glasses when

working with spring type hose clamps. Failure

to do so could result in eye injury.

6 Remove lower radiator hose (1) and u pper radiator

hose (2) from the radiator, after releasing the spring

type hose clamp, using suitabl e pli ers.

7 Remove the coolant recovery and va pour vent

hoses (3) from the radiator filler neck.

Figure 6B4 – 72

NOTE

If fitted with air conditioning, the condenser must

be separated from the radiator assembly. This

action will allow the radiator removal without

having to open any refrigerant lines.

8 Remove the radiator grille. Re fer to Section 1C Radiator Grille.

Engine Cooling – GEN IV V8 Page 6B4–63

Page 6B4–63

9 Working through the grille ope nin g, release one of

the clips securing the condens er to the radiator (bold

arrow). Do this by pressing down on the l ug with the

fingers of one hand, while lifting the condenser

assembly with the other. Repeat for the other side.

NOTE

It is not necessary to remove t he receiver drier,

nor disturb the air conditioning refrigerant

system (where fitted), for this operation. The

condenser can be lifted a s ufficient am ount with

the refrigerant pipes remaining attached.

10 Once released, pull the condenser assembly forward

to clear the radiator mounting lugs.

Figure 6B4 – 73

11 If vehicle is equipped with an automatic tran smission,

disconnect the transmission oil cooler line quick

connect fittings, using Tool No . AU525:

a Open release tool AU525, then close a nd clip

around the pipe to be disconnected.

b While holding the flexible hose (1) with on e

hand, push the tool into connection, to releas e,

and then pull back on the pipe (2) (or hose).

NOTE

If Tool No. AU525 is not available, the cooler

pipes can be disconnected from the cooler, in

the right side radiator tank. Refer to

3.16 Fle xible Transmission Cooler Hose, in this

Section, for important information regardi ng this

procedure.

c Plug all openings to minimis e fluid loss and

prevent dirt entry.

Figure 6B4 – 74

12 Using a screwdriver, compress and lever out radiator

retaining clips (1) from radiator upper mounting

brackets.

13 Lift radiator upwards out of lower insulators. To

remove the radiator assembly from the vehicle, after

clearing the top insulators, move the radiator

rearward on the left side, then across to the left, to

allow the right side to clear the mounting br ackets.

14 Remove upper and lower insulators from the radiator.

Figure 6B4 – 75

Engine Cooling – GEN IV V8 Page 6B4–64

Page 6B4–64

Install

Installation of the radiator is the reverse of removal procedures, noting the following points:

1 Before installing radiator, inspect core to ensure that there is no foreign matter such as insects in the core fins.

Clean out between core fins with compressed air, working from the engine side a nd blowing forwards.

2 Ensure that radiator lower mounting pins are correctly loc ated in lower insulators.

3 Ensure that upper insulators are insta lled on each of the upper mounting pins and radiato r retainers are correctly

installed on each side of the radi ator by checking that the clips engage on both sides of the channel support

bracket.

4 If the vehicle is fitted with an automatic transmission, remove plugs from the removed cooling pipe ends and the

two quick connect fittings.

5 After wiping cooler pipe ends and smearin g clea n automatic transmission fluid over each flared pipe end, push into

the quick connect fitting to engage. As a security check, tug on each pipe to ensure correct engagement.

NOTE

If the transmission cooler pipe tube nuts were

removed from the right hand radiator tank,

inspect the sealing washer for serviceability

before reinstallation. Replace the sealing

washer(s) as required. Tighten the cooler pipe

tube nut to the correct torque specification.

Oil cooler pipe tube nut

torque specification...............................................25 Nm

6 Check the transmission fluid level. Refer to the follo wing references as required:

• Section 7C4 Automatic Transmission – 4L60E On-vehicle Servicing

• Section 7E4 Automatic Transmission – 5L40E On-vehicle Servicing

7 After reinstalling the condenser assembly to the four retaining clips, ensure that the two lower clips have fully

engaged.

8 Install the radiator grille. Refer to Section 1C Radi ator Grille.

9 Install the following hoses:

a Lower radiator hose, securing with the hose clamp.

b Upper radiator hose, securing with the hose clamp.

c Coolant recovery and vapour vent hoses to the radiator filler neck.

10 Install the radiator cooling fans and shroud assembly. Refer to 3.14 Cooling Fans and Shroud Assembly in this

Section. Ensure that electrical connectors and the transmission cooler lines are seated correctly in the integral

retainer clips before install upper rad iator shroud.

11 Refill cooling system, refer to 3.3 Draining and Filling Cooling System in this Section.

12 Check for coolant leaks. Refer to 3.8 Pressure Testing in this Section.

13 Reconnect battery ground lead. Refer to Section 12A B attery.

14 Check cooling fan operation. Refer to Section 6C4-2 Engine Management – GEN IV V8 – Diagnostics, including

fan rotation direction.

Engine Cooling – GEN IV V8 Page 6B4–65

Page 6B4–65

Radiator Repair Procedure

Repairable Leaks

Figure 6B4 – 76

Legend:

1 Left-hand Side Tank Seal

2 Core Tubes

3 Right-hand Side Tank Seal

4 Oil Cooler Pipe Fittings

5 Joint Between Tube and Header

There are two types of leaks that can b e rep aire d on the aluminium-plastic radiator; core leaks and automatic

transmission oil cooler seal leaks. Leaks in the plastic tanks or the seals between the side tanks and the headers cannot

be repaired, requiring the radiator to be replaced.

Core leaks may occur in a tube or in the joints between the tubes and the headers. Seal leaks may occur in the joints

between the plastic tanks and the headers or in the joints between the oil cooler fittings and the tank (vehicles with

automatic transmission).

While some leaks may be repaired while the radiator remains installed, it is strongly recommend ed that the radiator is

removed from the vehicle before attempting any repairs.

NOTE

Minor damage to tubes, or tube to header joint

(holes up to 1 mm diameter max.) can be

repaired. Core replacement is necessary if

damage is any greater.

Engine Cooling – GEN IV V8 Page 6B4–66

Page 6B4–66

Repair Method

Repairs to the aluminium radiator core should only be made using the recommended 'Aluminised Silicon' based liquid

repair agent, in accordance with the recommended procedur e out lined in General Core Repair, further on in this Section.

Refer to current release of Partfinder™ for the Aluminised Si licon base liquid part number.

For damaged areas that are between the cooling fi ns, it

may be necessary to remove some of the fins. Do not

remove more fins than is necessary. Usually 6 mm

(distance ‘A’) beyond the leak or dama ge area, up to a

maximum of 25 mm of total fin material, is enough to make

an effective repair.

Figure 6B4 – 77

Tube Blocking

If a tube is severely damaged, it can be blocked off.

NOTE

Do not block off more than two tubes in a

radiator. Blocking off more than two tubes will

reduce the cooling capacity and efficiency of

the system and possibly result in an

overheated engine.

The tube should be cut off 6 mm from the header (1) and

pinched shut before it is clean ed and sealed. Refer to

General Core Repair, further on in this Section.

Figure 6B4 – 78

Header Repair

If the header or a tube near the header requires a repair, the side tank is not to be removed. If the repair requires the

removal of the header tank, then the radiator must be replaced.

Engine Cooling – GEN IV V8 Page 6B4–67

Page 6B4–67

General Core Repair

NOTE

The need for careful preparation of the surface in

the repair area cannot be over-emphasised. If the

leak area surface is not clean, the repair material

will not adhere to the surface.

1 Drain the cooling system. Refer to 3.3 Draining and Filling Cooling System in this Section. Remove the radiator.

Refer 3.15 Radiator – Remove, in this Section.

2 If necessary, carefully cut away fins to expose the damaged area.

NOTE

Do not cut away more than 25 mm total of fin

material.

3 Clean away dirt etc. with water. Dry the affected area using hot air from a hair drier.

NOTE

Do not apply flame to dry damaged area.

4 Clean affected area with petrol to remove any traces of oil.

5 Thoroughly stir contents of repair agent. In cases of extended shelf life, the silicon in solution may separate from

the thinner carrier. Should this occur, mix contents well until agent is homogeneous again.

6 Apply repair agent sparingly to damaged area. Do not apply an excessive amount, as this will cause a blockage of

the radiator tube.

Use a clean, dry wooden applicator to 'drip' the repair agent onto damaged area of radiator.

7 Allow radiator to stand in a clean, dry area for a minimum of three hours (at ambient temperature of 20 – 30° C)

with adequate ventilation.

Do not apply flame to dry damaged area.

8 Install radiator. Refer to 3.15 Radiator – Install in this Section.

Transmission Oil Cooler Leak Test

If the transmission oil cooler is suspected of leaking transmission fluid, test it before replacing the radiator, as follows:

1 Disconnect oil cooler pipes from the flexible hose connections using release tool AU525.

2 Using suitable connections plug one of the flexible hoses and connect an air supply to the other.

3 Lay the radiator flat on a bench top and fill with clean water until both hose fittings are full and visible.

4 Apply air pressure GRADUALLY, increasing it up to a maximum of 120 kPa.

If bubbles appear in the water visible in the radiator hose fittings, then the radiator assembly must be replaced.

Transmission Oil Cooler Seal Replacement.

It is strongly recommended that the transmission oil cooler connector fittings to the right-hand side radiator header tank,

not be disturbed. If coolant is found to leak from ether of these two areas then the radiator should be replaced.

Engine Cooling – GEN IV V8 Page 6B4–68

Page 6B4–68

3.16 Flexible Transmission Cooler Hose

LT Section No. – 04 – 150

Replace

NOTE

The flexible hoses are not serviced separately.

Therefore, should a hose require replacement,

then the hose and radiator to hose cooler pipe

assembly must be fitted.

1 Place a drip tray beneath the engine and radiator

section.

2 Disconnect the transmission cooler pipe(s) from the

flexible hose(s) using Tool No. AU525.

3 Open release tool AU525, then close a nd clip around

the pipe to be disconnected.

4 While holding the flexible hose (1) with on e hand,

push the tool into connection, to release, and then

pull back on the pipe (2) (or hose).

5 Repeat for the second fitting, if required.

6 Plug both pipe openings and hoses to minimise fluid

loss and prevent foreign matter entry.

Figure 6B4 – 79

7 If removing the upper automatic transmission cooling

pipe (1), then release it from the integral clip (2) on

the fan shroud.

Figure 6B4 – 80

Engine Cooling – GEN IV V8 Page 6B4–69

Page 6B4–69

8 Using a suitable set spanner, loosen the cooler pipe

tube nut (1), then remove, taking care not to lose the

sealing washer (2). Plug both open ends to prevent

fluid loss and / or dirt entry.

NOTE

A back-up spanner must be used on the larger

cooler, flare nut fitting (3) to prevent it from

loosening.

9 Repeat for the second pipe / hose assembly.

10 Before installing each pipe to the cool er, carefully

inspect the pipe-sealing washer. If the centre, silicone

portion shows signs of distress or damage, it must be

replaced.

11 Remove the plugging from the pipe and fittings, fit the

sealing washer to the clean ed pipe and install into the

cooler.

12 Install the tube nut and tighten to the correct torque

specification.

Oil cooler pipe tube nut

torque specification...........................................25 Nm

NOTE

A back-up spanner must be used on the larger

cooler, flare nut fitting (3) to prevent it from

loosening.

Figure 6B4 – 81

13 Check the transmission fluid level. Refer to the following references as required:

• Section 7C4 Automatic Transmission – 4L60E On-vehicle Servicing

• Section 7E4 Automatic Transmission – 5L40E On-vehicle Servicing

Engine Cooling – GEN IV V8 Page 6B4–70

Page 6B4–70

4 Engine Cooling System

Diagnosis

4.1 Poor Heater Operation

Little or no heat coming from the heater, especiall y at idle could be an indication of a cooling system problem.

As the coolant level begins to get lower than normal, air enters the system to replace the missing coolant. The heater

core is one of the highest parts of the cooling system and therefore, the first area to lose coolant circulation.

At first, with a small amount of coolant loss, lack of heat will be most noticeable at idle. As driving spee d increases, the

engine pumps more coolant a nd more heat is now able to pass through the heater core.

If coolant level drops even lower, heater operation will become less effective, even during normal driving. Cooling and

engine systems can be adversely affected if problem is not corrected b efore overheating occurs.

Engine Cooling – GEN IV V8 Page 6B4–71

Page 6B4–71

4.2 Leaking Cylinder Head Gasket

Combustion gases leaking past the cylinder head gasket can pressurise the cooling s ystem, forcing coolant out of the

system and into the coolant recover y res ervoir.

Indications are air bubbles in the coolant or an overflow condition of the recovery reservoi r.

Engine Cooling – GEN IV V8 Page 6B4–72

Page 6B4–72

4.3 Question the Customer

To avoid needless time and c ost in diagnosing cooling s ystem complaints, the customer should be questioned ab out

driving conditions that place abnormal loads on the cooling system.

1 Is overheating occurring after prolonged idle, in gear, with air conditioni ng system operating?

If answer is YES – instruct owner on driving techniques that would avoid overheating such as:

• Idle in neutral as much as possible – increase engine rpm to get higher air flow (due to an increase in voltage

to the fan) and coolant flow through the rad iator.

• Turn air conditioning s ystem off during extended idling periods if overheating is indicated on temperature

gauge. Further diagnostic che cks should not be required.

2 Is overheating occurring after prolong ed driving in slow city traffic, traffic jams, parades, etc?

If answer is YES, explain driving technique to the customer, that would avoid overheating – same as for prolonged

idle – No.1. Further diagnostic checks should not be required.

Engine Cooling – GEN IV V8 Page 6B4–73

Page 6B4–73

4.4 Diagnostic Chart

If none of the above conditions apply, refer to the following Diagnosis Chart.

To effectively use this chart, question the customer to determine which of the following three categories app ly to the

complaint:

1 If complaint is hot indication on temperatur e gauge.

Was temperature reading accompanied by boiling ?

• If answer is YES, go to overheating on diagnosis chart.

• If answer is NO, check temperature gauge and sender.

2 If complaint is boiling – go to overheating on diagnosis char t.

3 If complaint is coolant loss. Determine if customer is filling the system corr ectly.

4 If incorrect filling is not the problem, go to coolant loss in the diagnosis chart.

Refer to 3.1 Service Notes in this Section, for

important safety items before removing the

radiator pressure cap or servicing the system.

The cooling system is designed to operate at

95 to 120 kPa and temperat ures n o t exce edin g

130°C.

Cooling System Diagnosis

Step Action Result Yes No

1 Check Temperature gauge reading High Temp.

Low Temp.

Go to Step 2

Go to Step 6

–

2 Check drive belt condition and tension. Refer to

3.6 Engine Accessory Drive Belt Tension and

3.7 Engine Accessory Drive Belt in this Section. Refer

also to 6A4 Engine Mechanical – GEN IV V8 Engine.

Specification Go to Step 3 Replace drive

belt or

tensioner.

3 Check coolant Boiling Go to Step 4 Go to Step 5

4 Check coolant level. Refer to 3.2 Coolant Maintenance in

this Section. Low Go to Step 10 Go to Step 6

5 Check radiator cap. Refer to 3.8 Pressure Testing –

Radiator Cap Pressure Testing in this Section OK? Go to Step 8 Replace

Coolant filler

cap

6 Check thermostat. Refer to 3.9 Thermostat in this

Section. OK? Go to Step 9 Go to Step 13

7 Check Engine Coolant Temperature (ECT) sensor. Refer

to 6C4-2 Engine Managem ent – GEN IV V8 –

Diagnostics.

Faulty Replace Go to Step 12

8 Check cooling fan operation. Refer to 6C4-2 Engine

Management – GEN IV V8 – Diagnostics. Operational Go to Step 10 Rep air

9 Check for collapsed upper or lower radiator hose. Collapsed Replace Go to Step 13

10 Visual system check Leaks Go to Step 13 Go to Step 11

Engine Cooling – GEN IV V8 Page 6B4–74

Page 6B4–74

Step Action Result Yes No

11 Check coolant concentration. Refer to 3.2 Coolant

Maintenance – Testing Coola nt Conce ntratio n. To

Specification Go to Step 12 Correct

Concentration

Level

12 Check radiator core for bent fins, dirt, bugs or other

obstructions. Obstructed Clean or

straighten Go to Step 14

13 Pressure Test cooling system. Refer to 3.8 Pressure

Testing – Cooling System Pressure Testing in this

Section.

Leaks Repair System OK

14 If none of the above require repair, the problem is out of

ordinary or of a major natur e. Listed below are two

groups of problem areas that should b e checked in the

order as shown.

Engine Cooling – GEN IV V8 Page 6B4–75

Page 6B4–75

4.5 Problems Not Requiring Disassembly of

Cooling System

1 Large obstructi ons blocking radiator or condenser airflow.

• Auxiliary oil coolers.

• License plate.

• Obstruction of radiator grille, for example, driving lights or mud.

2 Loose, damaged or missing a ir chute side panels.

3 Missing or damaged air baffle.

4 Cracked or loose coolant recover y system hos e.

5 Leaking heater compon ent such as the heater core or water valve.

Engine Cooling – GEN IV V8 Page 6B4–76

Page 6B4–76

4.6 Problems Requiring Disassembly of

Cooling System

1 Damaged cooling fan or faulty motor operation.

2 Pressure test cooling system.

3 Defective coolant pump.

• Eroded or broken impeller van es.

• Failed bearing or seal – check for shaft or bearing end play.

4 Internally blocked radiator core.

5 Obstruction of coolant recovery system.

6 Internal system leaks.

• Head gaskets.

• Cracked cylinder block.

• Engine front cover.

• Intake manifold gaskets.

7 Blocked coolant passages in cylinder heads or block – remove cylinder hea ds and ch eck.

8 Blocked or damaged vapour vent s ystem.

Engine Cooling – GEN IV V8 Page 6B4–77

Page 6B4–77

4.7 Black Light and Dye Leak Diagnosis

Method

It is strongly recommended that the black light and dye method be used to diagnose and locate fluid leaks. This method

of leak detection is a proven, reliable method that identifies the specific leak source and / or location. The black light kit is

suitable for various types of leak detection, when used with the appropriate tracer dye and can be used for detecting

engine coolant, engine oil, transmission fluid, and air conditioning refrigerant leaks. The following is a summary of the

steps involved in detecting a cooling system fluid leak using black li ght and dye.

Adding dye to the GEN IV V8 engine cooling

system, may chang e the colour of the coolant

from an orange colour to a dark, muddy

green. As the use of extended life anti-freeze

coolant (conforming to GM6277M) to this

cooling system is mandatory and is not to be

mixed with other composition coolants, the

green colour could be misleading for future

top-up operations.

Therefore, should the coolant change colour

when the leak detection dye is added, then

the cooling system MUST be drained and n ew

extended life anti-freeze coolant (conforming

to GM6277M) coolant added. Refer to

3.3 Draining and Filling Cooling System, in

this Section.

1 Pour specified amount of dye into the cooling system via the coolant filler cap on the radia tor. Refer

3.1 Service Notes in this Section.

2 Road test the vehicle under normal operati ng conditions.

3 Direct the black light towards the suspect area. Any fluid leak will app ear as a brightly colour ed path leading to the

source.

4 Repair fluid leak and recheck to ensure that leak has been rectified.

5 Refer to the manufacturer’s directions when using this method.

Engine Cooling – GEN IV V8 Page 6B4–78

Page 6B4–78

5 Specifications

General

Radiator Cap Pressure Rating Nominal.......................................................................120 kPa

Cooling System Capacity

Automatic Transmission ................................................................................ 11.0 litres

Manual Transmission .................................................................................... 11.4 litres

Coolant Corrosion Inh ibitor

Automatic Transmission.................................................................................. 5.5 litres

Manual Transmission ...................................................................................... 5.7 litres

NOTE

DEX-COOL® long life coolant or equivalent, to

GM Specification 6277M, required when

changing coolant.

Thermostat

Type...............................................................................................Power element (wax pellet)

Starts to Open at.....................................................................................................86 ± 1.5° C

Fully Open at .................................................................................................................100° C

Coolant Pump

Type.........................................................................................................................Centrifugal

Drive.........................................................................................Multi-ribbed, Serpentine V-belt

Bearing Type ......................................................................................Double-row ball bearing

Radiator

Core Type........................................................................................ Aluminium crossflow core

Overall Width...............................................................................................................826 mm

Overall Height..............................................................................................................495 mm

Core Width...................................................................................................................674 mm

Core Height .................................................................................................................427 mm

Core Thickness..............................................................................................................35 mm

Plastic Tanks ...............................................................................Nylon 6,6 (30% Glass Filled)

Radiator Hoses

Lower – Number and type ................................................................................. One, Moulded

Upper – Number and type ................................................................................. One, Moulded

Engine Cooling – GEN IV V8 Page 6B4–79

Page 6B4–79

Small Engine Cooling Fan (LHS) 400W

Electric motor drive (Nominal Power Rating) ....... 180 Watts

Rotational Speed (with 12 volts applied,

Radiator and Condenser installed)

– Stage 1 .................... 2,350 ± 150 rpm

– Stage 2 .................... 2,750 ± 150 rpm

Number of Blades...................................................................................................................5

Fan – Design ..........................................Asymmetrical spaced, curved blades with outer ring

Material..................................Nylon 6,6 (30% Glass Filled), with zinc coated metal hub insert

Diameter......................................................................................................................293 mm

Fan Motor – Type .........................................Dual-speed, 4 brush with 4 permanent magnets

Housing ...........................................................Semi-sealed, zinc-coated steel with drain hole

Direction of Rotation.............................................. Anticlockwise (as viewed from motor side)

Large Engine Cooling Fan (RHS) 400W

Electric motor drive (Nominal Power Rating) ....... 220 Watts

Rotational Speed (with 12 volts applied,

Radiator and Condenser installed)

– Stage 1 .................... 2,050 ± 150 rpm

– Stage 2 .................... 2,300 ± 150 rpm

Number of Blades...................................................................................................................5

Fan – Design ..........................................Asymmetrical spaced, curved blades with outer ring

Material..................................Nylon 6,6 (30% Glass Filled), with zinc coated metal hub insert

Diameter......................................................................................................................354 mm

Fan Motor – Type .........................................Dual-speed, 4 brush with 4 permanent magnets

Housing ...........................................................Semi-sealed, zinc-coated steel with drain hole

Direction of Rotation.............................................. Anticlockwise (as viewed from motor side)

Pressure Transducer

Low Pressure Cut Out .................................................................................................180 kPa

Low Pressure Cut In....................................................................................................240 kPa

High Pressure Cut Out..............................................................................................2,970 kPa

High Pressure Cut In ................................................................................................1,900 kPa

Engine Cooling – GEN IV V8 Page 6B4–80

Page 6B4–80

6 Torque Wrench Specifications

Coolant Pump to Cylinder Block Bolts:

Stage 1.........................................................................................15 Nm

Stage 2.........................................................................................25 Nm

Coolant Pump Rear Cover Bolts .............................................................14 Nm

Engine Accessory Drive Belt Tensioner Bolt...........................................50 Nm

Fan Motor to Shroud Screws.....................................................................5 Nm

Oil Cooler Pipe to Oil Cooler Tube Nut ...................................................25 Nm

Oil Pan Under-Tray Bolts.........................................................................30 Nm

Thermostat Housing to Coolant Pump Bolts............................................14 Nm

Engine Cooling – GEN IV V8 Page 6B4–81

Page 6B4–81

7 Special Tools

Tool number Illustration Description Classification

AU505

COOLANT TESTER

Used for testing the coolant

concentration level.

Previously released.

Mandatory

AU525

QUICK CONNECT RELEASE TOOL

Used to release the quick connect

fittings on the automatic transmission

fluid cooler lines at the radiator end,

when the vehicle is so equipp ed.

Previously released.

Mandatory

J 26568

REFRACTOMETER

Used for testing coolant concentration

level. Previously released, as AU 435.

Mandatory

J28431–B FLUID DYE

Available in 24 x 1-ounc e bottles.

Used in conjunction with a black light

such as J42220 to locate the source

of various fluid leaks.

Previously released.

Desirable

J42220 BLACK LIGHT, LEAK DETECTION

LAMP

Used with dye, J28431–B to locate the

source of various vehicle fluid leaks.

Previously released.

Desirable

N/A COOLING SYSTEM PRESSURE

TESTER

Commercially available.

Mandatory