Engine Cooling - GEN III V8 Engine Page 6B3–1

Page 6B3–1

Section 6B3

Engine Cooling - GEN III V8 Engine

ATTENTION

Before performing any Service Operation or other procedure described in this Section, refer to Section 00

CAUTIONS AND NOTES for correct workshop practices with regard to safety and/or property damage.

1 General Information............................................................................................................................... 2

1.1 General Description................................................................................................................................................2

Cooling Fans...........................................................................................................................................................2

Operation............................................................................................................................................................3

2 Service Operations................................................................................................................................8

3 Engine Cooling System Diagnosis ...................................................................................................... 9

4 Specifications....................................................................................................................................... 10

Small Engine Cooling Fan – (Left) ......................................................................................................................10

Large Engine Cooling Fan – (Right) ...................................................................................................................10

Techline

Engine Cooling - GEN III V8 Engine Page 6B3–2

Page 6B3–2

1 General Information

With the following exceptions, MY 2003 VY Series cab Chassis GEN III V8 cooling system information carries over from

MY 2003 VY Series vehicles. For information not contained within this Section, refer to Section 6B3, Engine Cooling -

GEN III V8 Engine in the VY and V2 Series Service Information.

• A unique series /parallel cooling fan circuit that includes an additional relay has been introduced.

• The cooling fans mounted behind the radiator are equipped with high power electric motors.

• The cooling fan wiring and connectors are unique.

1.1 General Description

Cooling Fans

The cooling system for the GEN III V8 engine, includes two, double speed, engine cooling fan motors, both of which,

drive fans with five asymmetrical blades. The larger, right fan is 342 mm in diameter and has a motor rated at 215 Watts

(nominal), while the smaller, left fan is 293 mm in diameter with a motor power rating of 215 Watts (nominal).

With 12 volts applied and the fans mounted to the radiator with a condenser fitted, the operating speeds are:

Stage 1 Stage 2

Large Fan 1200 ± 150 rpm 2400 ± 150 rpm

Small Fan 1700 ± 150 rpm 3000 ± 150 rpm

Figure 6B3-1

Engine Cooling - GEN III V8 Engine Page 6B3–3

Page 6B3–3

Legend (Figure 6B3-1)

1. Fan Shroud

2. Radiator

3. Fan Shroud Lower Support

4. Fan Shroud Upper Support/Locking Retainer

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

6. Small, Left Fan Motor – 215 Watt, Double Speed

7. Left Fan Motor Harness Connector (2 Terminal)

8. Left and Right Fan Motor Harness Connector (4

terminal)

9. Large, Right Fan – 5 Blade, 342 mm Diameter

10. Large, Right Fan Motor – 215 Watt, Double Speed

11. Oil Cooler, Lower Quick Connect Fitting (Auto. Trans

Only)

12. Oil Cooler, Upper Quick Connect Fitting (Auto. Trans

Only)

Operation

To achieve the dual speed requirement, the electrical circuit for the GEN III V8 cooling fans as fitted to MY 2003 VY

Series Cab Chassis Models incorporates an additional relay. This relay is required to switch from a series circuit during

stage 1 cooling fan operation, to a parallel circuit at stage 2 cooling fan operation. This new series/parallel cooling fan

switching arrangement has been introduced into MY2003 VY Series Cab Chassis Models to prevent contacts from

overload, as well as headlamp or instrument illumination from variations that would have occurred with the use of the

new larger fan motors and the existing 3/4 parallel switching arrangement used on MY2003 VY Series Sedan and

Wagon Models.

The positive terminals of the cooling fans are permanently connected to battery voltage, via fusible links F101 (both fans

at stage 1 and large fan at stage 2) and F107 (small fan at fan stage 2).

Engine Cooling - GEN III V8 Engine Page 6B3–4

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Stage One Fan Operation

Figure 6B3-2

Engine Cooling - GEN III V8 Engine Page 6B3–5

Page 6B3–5

The PCM determines when the engine cooling fans should operate at stage 1 (i.e. engine cooling fan relay 1 should be

energised), based on inputs from the A/C request signal, Engine Coolant Temperature (ECT) sensor and the Vehicle

Speed Sensor (VSS). The PCM will then send a message on the Class 2 serial data circuit to the PIM. The PIM will then

convert the PCM Class 2 message to a UART message and supply this UART message to the BCM, via a serial data

Normal Mode Message to the BCM on circuit 800 (Red/Black wire). This message will request the BCM to supply the

necessary ground signal for the engine cooling fan relay 1 (R5) to operate.

When engine cooling fan relay 1 is turned ON (energised), stage 1 fan operation is achieved by supplying battery voltage

(via fusible link F101) through the large, right cooling fan and relay 2 (R7), then on through the small, left cooling fan and

relay 1 (R5) to ground.

After the BCM provides the ground signal for the engine cooling fan relay 1, the BCM will send a message back to the

PIM confirming that the ground signal was commanded. A failure in this BCM response communication, will cause a PIM

DTC B2002 to set.

The engine cooling fan relay 1 (R5) will be turned ON when:

• The A/C request indicated (YES) and either:

• the vehicle speed is less than 30 km/h or;

• A/C pressure is greater than 1500 kPa or;

• The coolant temperature is greater than 98° C or;

• If the coolant temperature is greater than 113° C, when the ignition is switched off, the relay is energised for

approximately four minutes, this is known as Low Fan Run On, or;

• If an engine coolant temperature sensor fault is detected and a DTC such as DTC P0117, P0118, P1114 or P1115

is set.

The engine cooling fan relay 1 will be turned OFF when any of the following conditions have been met:

• An A/C request is not indicated (NO) and the coolant temperature is less than 95° C, or;

• An A/C request is indicated (YES) and the vehicle speed is greater than 50 km/h and A/C pressure is less than

1,170 kPa and the coolant temperature is less than 98° C.

Engine Cooling - GEN III V8 Engine Page 6B3–6

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Stage Two Fan Operation

Figure 6B3-3

Engine Cooling - GEN III V8 Engine Page 6B3–7

Page 6B3–7

The switching of the engine cooling fans to stage 2 operation is controlled directly by the PCM. To achieve stage 2 fan

operation, the engine cooling fan relay 2 (R7) and engine cooling fan relay 3 (R6) are provided with a ground signal by

the PCM. When engine cooling fan relay 2 is turned ON (energised), it connects the negative terminal of the large, right

cooling fan directly to earth, taking the small, left cooling fan out of the circuit and consequently increasing the speed of

the large, right fan. When engine cooling fan relay 3 is turned ON (energised), it supplies battery voltage (via fusible link

F107) to the positive terminal of the small, left cooling fan, then through relay 1 (R5) to ground.

Cooling fan relay 3 (R6) is a standard four-pin type relay. During the change from stage 1 to stage 2 fan operation, the

left, small cooling fan is switched to maximum speed by supplying battery voltage via fusible link F107.

The PCM will only activate stage 2 fan operation, if the engine cooling fan relay 1 has been ON (energised) for two

seconds and the following conditions are satisfied:

• There is a BCM message response fault which will cause a PIM DTC B2002.

• An engine coolant temperature sensor fault is detected and a DTC such as DTC P0117, P0118, P1114 or P1115 is

set.

• Coolant temperature greater than 108° C.

• The A/C refrigerant pressure is greater than 2400 kPa.

If the engine cooling fan relay 1 was OFF when the criteria was met to activate engine cooling fan relay 2, stage 2 fan

operation will occur, 5 seconds after the engine cooling fan relay 1 is turned ON. If both engine cooling fan relays are

ON, the PCM will turn OFF engine cooling fan relay 2 when:

• The engine coolant temperature is less than 102° C.

• A/C request not indicated (NO).

• A/C request indicated (YES) and A/C pressure is less than 1900 kPa.

NOTE

Both cooling fans will be turned off if the vehicle

speed is greater than 104 km/h.

NOTE

The PCM determines operation of the two, two-

speed engine cooling fans based on A/C request,

A/C system pressure, 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 6C3,

Powertrain Management – GEN III V8 Engine in

this Service Information.

Engine Cooling - GEN III V8 Engine Page 6B3–8

Page 6B3–8

2 Service Operations

With the following exceptions, MY 2003 VY Series Cab Chassis GEN III V8 cooling system carries over from MY 2003

VY Series vehicles. For service operation information not covered in this Section, refer to Section 6B3, 2. Service

Operations in the VY and V2 Series Service Information.

• The wiring connectors for the cooling fans have been revised.

NOTE

Although the wiring connectors for the cooling

fans has been revised, the service operations

remains unchanged from those provided in to

Section 6B3, 2. Service Operations in the MY

2003 VY and V2 Series Service Information.

For details about the revised wiring connectors,

refer to Section 6C3, Powertrain Management -

GEN III V8 Engine in this Service Information.

Engine Cooling - GEN III V8 Engine Page 6B3–9

Page 6B3–9

3 Engine Cooling S ystem

Diagnosis

With the following exceptions, MY 2003 VY Series Cab Chassis GEN III V8 cooling system carries over from MY 2003

VY Series vehicles. For diagnostic information not covered in this Section, refer to Section 6B3, 3. Engine Cooling

System Diagnosis in the VY and V2 Series Service Information.

• The cooling fans mounted behind the radiator are equipped with high power electric motors.

• The wiring to the cooling fan motors is unique.

• The cooling fan circ uit includes an additional relay.

NOTE

For information regarding the general diagnosis

of the mechanical portion of the engine cooling

system as fitted to MY2003 VY Series Cab

Chassis Models equipped with a GEN III V8

engine, refer to Section 6B3, 3. Engine Cooling

System Diagnosis in the VY Series and V2 Series

Service Information.

For information regarding the electrical diagnosis

of the engine cooling fan circuit as fitted to

MY2003 VY Series Cab Chassis Models

equipped with a GEN III V8 engine, refer to

Section 6C3, Powertrain Management - GEN III

V8 Engine in this Service Information.

Engine Cooling - GEN III V8 Engine Page 6B3–10

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4 Specifications

Small Engine Cooling Fan – (Left)

Fan

Type........................................................Asymmetrical spaced, curved blades with outer ring

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

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

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

Fan Motor

Type .............................................................Dual speed, 4 brush wi th 4 permanent magnets

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

Direction of Rotation.......................................Counter-clockwise (as viewed from motor side)

Power....................................................................................................... 215 Watts (nominal)

Rotational Speed (Radiator and Condenser Installed)

Stage 1........................................................................................................... 1,700 ± 150 rpm

Stage 2........................................................................................................... 3,000 ± 150 rpm

Large Engine Cooling Fan – (Right)

Fan

Type........................................................Asymmetrical spaced, curved blades with outer ring

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

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

Diameter ..................................................................................................................... 342 mm

Fan Motor

Type.............................................................. Dual speed, 4 brush with 4 permanent magnets

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

Direction of Rotation.......................................Counter-clockwise (as viewed from motor side)

Power....................................................................................................... 215 Watts (nominal)

Rotational Speed (with 12 volts applied, Radiator and Condenser Installed

Stage 1........................................................................................................... 1,200 ± 150 rpm

Stage 2........................................................................................................... 2,400 ± 150 rpm