vx berlina radiator fan not coming on.

[vs gary]

hi. can someone please tell me if both radiator fans come on at the same time when it gets a bit over half way or only one.i let it run in park for a while till it heated enough for the fan to come on. it has 2 but only one come on. my wife has said it gets up in the red sometimes coming back from work. i have checked the coolant. might be when she is in traffic????or it might be that both fans arent coming on. thanks. gary.

 

[BlackVXGTS]

Refer to the description below. In general, with A/C off, the low speed fan turns on when the temperature is over 104C and the high speed fan if the temperature is over 109C.

CIRCUIT DESCRIPTION:
This V6 engine have two (2) two speed electric radiator fan motors which provides the primary means of moving air through the engine radiator. The two (2) two speed electric cooling fan's are used to cool engine coolant
flowing through the radiator. It is also used to cool the refrigerant flowing through the A/C condenser. The engine cooling fan high speed relay is controlled by the PCM. The PCM controls the earth path for the
engine cooling fan high speed relay. The low speed of the electric fan is controlled by the PCM through special Data Communication to the BCM. The BCM controls the earth path for the engine cooling fan low speed relay.
Both relays are used to control the earth paths to the electric motor's that drives both five bladed fans.

ENGINE COOLING FAN LOW SPEED.
The engine cooling fan low speed relay is energised by the BCM. The PCM determines when to enable the engine cooling fan low speed based on inputs from the A/C request signal, vehicle speed and engine coolant
temperature. The engine cooling low speed fan will be turned "ON" when:
• A/C request indicated (YES) and
• Vehicle speed less than 54 Km/h
or
• Coolant temperature is greater than 104 degrees C and will remain on until coolant temperature goes down below 99 degrees C

ENGINE COOLING FAN HIGH SPEED
The engine cooling fan high speed is controlled by the PCM based on input from the Engine Coolant Temperature Sensor (ECT). The PCM will only turn "ON" the engine cooling fan high speed if the engine cooling
low speed fan has been "ON" for 2 seconds and the following conditions are satisfied.
• There is a BCM message response fault which will cause a DTC 92.
• An engine coolant temperature sensor failure is detected, such as DTC 14,15,16,17, or 91.
• Coolant temperature greater than 109 degrees C.
If the fan low speed was "OFF" when the criteria was met to turn the fan high speed "ON", the fan high speed will come "ON" 5 seconds after the fan low speed is turned "ON". The engine cooling fan High speed relay can
also be enable by the A/C Refrigerant Pressure Sensor. The A/C Refrigerant Pressure Sensor will provide a signal to the PCM when A/C pressure becomes to high approximately 1770 kPa.

 

[Ozzie]

One fan is to cool down the radiator and the other is to cool down radiator and air con condenser/radiator.
The second fan wil only kick in when the aircon is switched on.
Completely normal

P.s. Sounds like you either have air in the system or the thermostat isn't opening as it should
I'd start with having it compression tested to make sure it's not a gasket. Check your oil for milkyness and check your coolant for signs of oil. If it's a bit brown don't worry as the radiator should have lube in it which is normal to prevent corrosion

 

[vs gary]

thanks for your help.gary.

 

[Husky]

One fan is to cool down the radiator and the other is to cool down radiator and air con condenser/radiator.
The second fan wil only kick in when the aircon is switched on.
Completely normal

P.s. Sounds like you either have air in the system or the thermostat isn't opening as it should
I'd start with having it compression tested to make sure it's not a gasket. Check your oil for milkyness and check your coolant for signs of oil. If it's a bit brown don't worry as the radiator should have lube in it which is normal to prevent corrosion

Not entirely correct. the passenger side fan is the low speed. It will come on at a set temperature OR when the AC is running. The driver's side fan is the high speed and comes on at a higher temperature. Both should operate even if the AC is off. My car was over heating the other week, turns out the low speed fan motor had died. Took a mechanic all of 30 minutes to swap it out with another and the car is fine now. It might be worth changing the low speed fan relay first.

 

[Waughy]

If the oil and coolant look ok, check under the oil cap. If there's milky sludge under there then it's possible the inlet manifold gaskets could be up for replacing. Does it require a top up once a week or so? My old Acclaim would beep HOT and the temp would shoot up, then come back down when I put the heater on. I checked the radiator after it had cooled and nothing in the neck. Top up and bleed, it would be good for about a week then start beeping etc again. Sludge under oil cap, so I bit the bullet and pulled the inlet manifold off. Sure enough the driver side gasket had failed around the front water jacket. About a day to replace, no issues over the next few weeks before I sold it. These gaskets are pretty common to fail on the ecotecs from about 150,000k onwards. I changed mine at 240, it looked like it had been bad for a while.

A pressure test should help determine if the gaskets could be bad, to save pulling the manifold off to find they're fine. But if the fans are working properly, and the oil and coolant look ok, then the gaskets could be worth investigating.

A split hose is another possibility. My parents had a VT that would beep and flash hot, but only over 80km/h. Ended up being a split heater hose, all good once it was replaced.

Also with the fans, if you get it up to temp so one fan kicks in, turning the aircon on will get the other one going from memory. I did this when investigating my issue above.