Radiator fans not working.

09-20-2011, 09:57 PM
I have a 2005 Pacifica, my wife had the upper radiator hose blow off last Thursday, and overheat, she pulled over and I went out to her location to see what may be wrong. I put the hose back on and filled it with water, everything appeared fine and we drove the last five miles home. It appears to be the radiator cap was bad, so I replaced it. It has not overheated since.

My question is this, I've been watching the fans and the car to see if it'll overheat again and it has not. But I have not seen the radiator fans come on at all. If I turn on the AC they come on, but if I turn off the AC the fans stop working. I have driven it around and have not heard them come on. Is it a faulty coolant temperature sensor? Or does the engine have to get really hot for the fans to come on? I seem to remember the fan coming on when one turns the car off, but since the radiator hose incident it has not. Since it is not my daily driver, I am not sure on that.

Tony Silva
09-20-2011, 10:25 PM
One of the fans come on when ever the A/C is being used. This is to pull air past the air conditioners (smaller) radiator. The other fan is temperature activated. If that one does not come on then you may have a problem. Some cars with small inefficient radiators will have the fan cycle on and off with the car just idling every 2 or three minutes. Case in point...Honda Accords and Civics. At idle...those fans turn on and off every couple of minutes. However, I used to have Camaro IROC Z and those fans hardly EVER came on. But the IROC was programmed by the factory to operate at higher engine temps to help clean up the tail pipe emissions.

Did you ever notice the fans turning on and off before the engine overheated (besides when the a/c was used. I would suggest however that you atleast replace the thermostat and add the proper amount of engine coolant to the cooling system. All that heat and pressure probably didn't do any good for it.

09-20-2011, 10:32 PM
I never noticed the fans come on before, it's not my daily driver, but my wife's. Just like I posted, I vaguely remember them coming on when the car was turned off. I'll be replacing the thermostat tomorrow, and the coolant sensor, just to be safe. And of course adding the right mix of coolant. Thanks for your quick reply.

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