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Ask GM Tech (Cam) Your Own Question
GM Tech (Cam)
GM Tech (Cam), Pontiac Technician
Category: Pontiac
Satisfied Customers: 29428
Experience:  GM Grand Master Technician 2007. 14 years experience.
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My 2004 pontiac grand prix gt cooling fan does not come on

Resolved Question:

My 2004 pontiac grand prix gt cooling fan does not come on until the temp rises above 3/4 hot. It does work when the AC is on. Do I need to change the temp sensor and relays? If so, where are they located under the hood.
Submitted: 8 years ago.
Category: Pontiac
Expert:  GM Tech (Cam) replied 8 years ago.
WelcomeCustomer The cooling fans are designed to come on when it gets much warmer than operating temp. The fact that they come on and go off indicates the fans and relays are working, and the temp that they come on at is then the question. Does the temp get into the red of just high on the gauge?
Customer: replied 8 years ago.
It actually gets almost to the red and then the fans come on. When this happens, I turn off the motor and the coolant comes out of the overflow onto the ground. Prior to this, the temp never went above halfway.
Expert:  GM Tech (Cam) replied 8 years ago.
OK, that's getting too hot. how cold is where you are at?
Customer: replied 8 years ago.
It is averaging about 60F degrees here in Calif right now.
Expert:  GM Tech (Cam) replied 8 years ago.
Ok, so the coolant freezing due to cold is not the issue. Its -30 here now, so I had to check. It sounds like the thermostat is the issue. I would start by changing it and flushing your coolant.
Customer: replied 8 years ago.
already done all of that.
Expert:  GM Tech (Cam) replied 8 years ago.
Ok, how long does it take to overheat? Will it do it idling or driving? Do you have heat in the car?
Customer: replied 8 years ago.
It gets hot in traffic. Stays ok while moving. No heat in the car. It just seems like it takes too long for the fans to come on.
Expert:  GM Tech (Cam) replied 8 years ago.
Ok, no heat in the car and overheating indicates a circulation issue like a water pump or a bad head gasket. The pressure build up will prevent proper circulation.
Customer: replied 8 years ago.
The thing is, when the AC is on the fan is working all the time and the temp stays below 1/2. If there was a circulation problem, wouldn't it get hot no matter what?
Expert:  GM Tech (Cam) replied 8 years ago.
True, but the lack of heat in the car is something. I would have your head gaskets checked. There is a test that will find combustion gases in the coolant.
GM Tech (Cam) and 4 other Pontiac Specialists are ready to help you
Customer: replied 8 years ago.
okay. thanks man.