My 1995 Camaro 3.4L engine cooling fan never runs. I tested the relay that controls the fan and it passed the test as described in the Haynes manual for 1993 to 2002 Camaros and Firebirds. I removed the relay and jumpered across to verify the cooling fan works and it did in fact work. I replaced the Temperature sensor adjacent to the thermostat – this I believe controls whether the cooling fan runs. I replaced the temperature sensor behind the power steering assembly – this I believe controls the water temperature indicator inside the vehicle.
I replaced the water pump, the thermostat, the radiator, the two sensors I mentioned above, and the heater bypass tube (it had a pinhole).
Is it possible that some other problem (e.g. a leak or a blown gasket) prevents the temperature of the coolant from being registered by this newly replaced sensor?
The last thing I would consider for replacement is the computer after which I would have to conclude the problem is something major.
One last item. When I experienced the pinhole leak coolant sprayed all over the engine before I could shut it down and replace the tube with the hole. I am experiencing a preponderance of white spoke (presumed to be burning off coolant) occasionally and not persistent. I did not experience the white smoke prior to replacing any of these components.
I have no evidence of coolant in my oil and the car at 109k has never burned oil.
It sounds as if you have changed everything in the cooling system short of the engine itself.
The first thing I would do is start the vehicle and turn on the A/C system. After about 30 to 45 seconds the cooling fans should come on. If not, then we know we have a problem getting the "command" to turn on the cooling fans.
If the cooling fans come on with the a/c then I can safely assume that the computer is working as it should and your problem lies elsewhere.
I noticed in your letter you talked about "white smoke" coming from the engine. If white smoke is coming out your tailpipe then this is a symptom of a blown head gasket or cracked head. If so, then engine repair is needed ASAP.
What I suspect is happening is the head gasket leaks enough to keep the water from circulating causing the engine to over heat and the fans to stay off.
The cooling fans on this model do not come on until the coolant is 235 (F). The only way you can get the coolant that hot without boiling over, is to have a pressurized system. This means no leaks in the cooling system. By pressurizing the system you are raising the boiling point of the coolant. If the cooling system is not pressurized the coolant will never get hot enough to tell the computer to "kick on" the cooling fans. This might be what caused your head gasket to blow was the pinhole leak you talked about. My advice is to seek professional help to properly diagnose your problem. It will save your sanity as well as your hair! A good shop is not expensive, they are priceless. There are about 2 more tests needed to verify your problem and its cause. They need to verify scanner data as well as check for carbon monoxide in your cooling system.
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