VS commodore thermo fan not working

[b and my vs commy]

my commy has same prob....thanx for this im learnig alot....gonna try this

 

[moneypit]

First post and sorry for the thread revival, but, my low speed fan comes on when tested by unplugging the sensor as described.
But
It does not come on when the air con is switched on.
It does not come on when the temp gets to the point it should (half way on the gauge)
It does not come on when the consult plug is activated with the paper clip and I only have an o2 sensor fault code wich I am in the process of fixing.
Only the high speed fan activates when the temp is up to three quarter, probably the ecu overide according to the thread.
I have checked the relay and it's ok
I have read this thread.

Any extra help to pinpoint the problem would be appreciated, thanks

 

[Howelligan]

I'm hoping that someone out there with some mechanical knowledge is still monitoring this thread. I'll start by declaring that my expertise extends to repairing broken/damage humans, & I am not at all mechanically comptent.
At present I am 'borrowing' a friend's VS Ute, which doesn't appear to have had a whole lot if TLC in the recent past. I first picked b it up in July. From then, until fairly recently, the temp guage hasn't climbed above around 1/4. However, since the weather has warmed up it is now inclined to get as high as 3/4. It's fine while the car is moving, but starts to climb as soon as it becomes stationary, &.in slow moving traffic.
A friend suggested 'simply bypassing' the thermal sensor. He made it sound extremely simple, however from what i've read here, & looking at the engine, it doesn't look/seem at all simple. So I'm hoping i can get some assistance here.
Looking under the bonnet it would seem that the cooling system is getting reasonably warm at times, as there is evidence that coolant has been spraying out of the radiator cap. There's also a smell of coolant when the guage rises. The radiator appears to be full of coolant & the reservoir has a 'normal' level.
The Thermal Fan does work, but it doesn't seem keen to switch on until the temp is apparently very high.
I'm hesitant to drive anywhere during the day, especially when it gets above 25 degrees. Any assistance would be greatly appreciated.

 

[Sumit]

Hi my car is having same problem i just recently changed the thermostate and filled it with new coolent since then its running fine but few weeks ago i discovered the fan is not working i called up on my friend he works with racv to have a look according to him the fan does not kick in unless the the system is really hot i mean 3/4 of the gauge he checked the fan by taking out the relay and connecting it direct the fan works he reccons the car cools itself when its driving and the fan sits idle till the collent reaches the 3/4 boiling. He could be right but iam confused too.

 

[ephect]

they have a 2 speed fan, low should come on around a quarter to half on the gauge. And the high speed comes on after that. If is getting to 3/4 only the high fan is coming on. The half sized 5 pin relay will be faulty and needs replacing. This has been the cause of mine a couple of times.

unless its still got air inside the system and our needs bleeding

 

[Immortality]

Correct. The thermofan does not kick in until the engine reaches 104°C

Generally speaking when your moving fast enough the airflow through the radiator is more than enough to keep the engine running at the thermostat temp.

If your car has aircon the fan should go when the aircon is on and you are stationary. Simply pop the bonnet and then have someone turn on the aircon at which time the thermofan should come on.

If that doesn't work try swapping the relay with another (the horn relay is a good candidate).