SECTION 6B1 - ENGINE COOLING - V6 ENGINE
IMPORTANT
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 I NFORMATI ON
The engine cooling system on WH Series Models with V6 engine carries over from VT Series Models with one
notable exception; WH Series Models with V6 engine use two single speed electric engine cooling fans; a low
speed fan and a high speed fan (as compared to; two, two speed electric cooling fans).
For information, including General Information, Service Operations, Specifications and Torque Wrench
Specifications, that is not covered in this Section, refer to Section 6B1-1 ENGINE COOLING - V6 ENGINE of the
VT Series I Service Information and Section 6B1-1 ENGINE COOLING - V6 ENGINE of the VT Series II Service
Information.
NOTE: The cooling sy stem for vehicles with V6 supercharged engines does not change for WH Series Models.
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1.1 COOLING FAN OPERATION
On WH Series Models with V6 engines, the engine cooling fan motors have two terminals; one positive and one
negative. The positive terminals are permanently connected to battery voltage. When the negative terminal is
connected to earth through the low speed cooling fan relay, the low speed cooling fan will operate. When the
negative terminal is connected to earth via the high speed cooling fan relay, both cooling fans will operate.
The low speed cooling fan operation is enabled when the low speed engine cooling fan micro relay (located in the
engine compartment relay housing, labelled Lo Fan) is energised by the Body Control Module (BCM) via a request
from the Powertrain Control Module (PCM). The PCM will request low speed fan enable and disable via serial data
communication to the BCM on circuit 1221 (Red/Black wire). After the PCM requests a change in the state of the
low speed relay (i.e. OFF to ON or ON to OFF), the BCM will send a serial data response message back to the
PCM confirming it received the message.
The PCM determines when to enable the low speed fan relay based on inputs from the A/C request signal, Engine
Coolant Temperature (ECT) sensor and the Vehicle Speed Sensor (VSS).
LOW SPEED FAN OPERATION
The low speed cooling fan relay will be turned ON when:
•Air conditioning request indicated (YES) and the vehicle speed is less than 30 km/h or
•Air conditioning pressure is greater than 1500 kPa or
•Coolant temperature is greater than 104°C or
•An engine coolant temperature sensor failure is detected by the PCM, refer to Section 6C1 POWERTRAIN
MANAGEMENT - V6 ENGINE for additional information.
•When the ignition switch is turned from ON to OFF and the engine coolant temperature is above 117°C. The
BCM will continue to energise the low speed engine cooling fan micro relay for approximately four minutes.
The PCM will request the BCM to switch off the low speed cooling fan relay when the following conditions have
been met:
•Air conditioning request not indicated (NO) and the coolant temperature is less than 99°C or
•Air conditioning reques t indicated (YES) with pressure les s than 1170 kPa, vehic le speed gr eater than 50 km /h
and coolant temperature less than 99°C.
HIGH SPEED FAN OPERATION
The PCM determines when to enable the high speed fan relay based on inputs from the ECT sensor. The high
speed cooling fan relay will be turned ON if the low speed cooling fan relay has been energised for one second and
the following conditions have been met:
•If there is a BCM message response fault, setting a DTC 92 or
•An engine coolant temperature sensor failure is detected by the PCM, refer to Section 6C1 POWERTRAIN
MANAGEMENT - V6 ENGINE for additional information or
•Engine coolant temperature is above 107°C or
•Air conditioning pressure is greater than 2000 kPa.
NOTE: If the low speed cooling fan is off when the criteria for turning the high speed cooling fan on are first met, the
high speed cooling fan will turn on 5 seconds after the low speed cooling fan is switched on.
If both the high and low speed cooling fans are enabled, the PCM will turn the high speed cooling fan off when:
•The engine coolant temperature is less than 103°C and
•Air conditioning request is not indicated (No) or
•Air conditioning request is indicated (Yes) and the pressure is less than 1500 kPa.
2. SERVICE OPERATIONS
Service Operations for the cooling system on vehicles with V6 engine carry over from those detailed in
Section 6B1-1 ENGINE COOLING - V6 ENGINE of the VT Series II Service Information, noting the following.
To accommodate the new engine cooling fans, a minor revision to the lower baffle air chute was made, however,
this revision does not effect the way the air chute attaches to the front of the vehicle.
If reinstalling a cooling fan, cooling fan motor or s hroud assem bly to a W H Series vehicle with a V6 engine, ref er to
4. TORQUE WRENCH SPECIFICATIONS in this Section for the correct torque wrench specifications.
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3. SPECIFICATIONS
ENGINE COOLING FAN 1 - LOW SPEED
Number of blades..................................... 5
Spacing..................................................... Even
Material..................................................... Polypropylene (20% glass filled)
Diameter................................................... 300 mm
Electric motor drive................................... 80 watts (nominal)
ENGINE COOLING FAN 2 - HIGH SPEED
Number of blades..................................... 4
Spacing..................................................... Even
Material..................................................... Polypropylene (7.5% glass filled)
Diameter................................................... 340 mm
Electric motor drive................................... 120 watts (nominal)
4. TORQUE WRENCH SPECIFI CATIONS
Nm
Cooling Fan and Shroud to Radiator Attaching Bolt ............. 3.0 - 4.5
Cooling Fan Motor Shaft Attaching Nut ................................ 4.9 - 7.4*
Cooling Fan Motor to Shroud................................................ 1.8 - 1.3
* Apply Loctite 243 or equivalent to Holden Specification HN 1256