Cooling fan runs all the time


#1

I have a 91 Cutlass Ciera, with a 3.3L V6. The fan runs as soon as I start the car, even when the motor’s cold. It makes it hard to warm it up, and puts an additional stress on an older motor. Can someone help with this?


#2

It’s called “Astro-Ventilation”. The theory being to pressurize the cabin and eliminate any chance of CO poisoning. There is no “off” position on the blower switch…


#3

Do you mean the cooling fan on the radiator or the heater fan?

From my reading of it, you mean the radiator fan. First off, do you have the climate control in either of the AC settings or the defroster? If so, the fan will run all the time in these modes. Secondly, is the check engine light on? Certain computer faults will put the engine in a mode that makes the fan run all the time. If either of those things aren’t the case, you need to probably check either the coolant temp sensor or the separate fan temp switch if it has one. Also check the fan relay.


#4
I am also a little confused if you mean the cabin fan or a radiator fan.  

Some cars seem to have cabin fans that will run all the time, it is normal for them, not a bad idea.  If you live in a cold area and park in an attached garage, it will mean getting a little colder on the first part of your trip. 

If it is a radiator fan, remember that most cars will have a radiator fan on anytime the A/C is on including any time the defrost is on.  

As for warming up the engine, that should not be an issue.  Your engine has a thermostat that blocks nearly all the flow to the radiator until the engine if fully warm.  The little heat you may loose by the small amount of bypass of coolant, will be made up by the extra effort the engine has to make to keep that fan running.

#5

If this is the engine fans it’s likely one of the following:

Coolant fan relay is failed on.

Engine coolant temp sensor has failed on.

The coolant temps sensor sends a signal to the engine computer, which in turn energizes the fan relay. That sensor also runs to the A/C sensor so as previously mentioned if your cab heating is set to A/C the fans will run all the time.

Try pulling the Dark Green & White wire of the fan relay, if the fan stops, the relay is okay. If it keeps running, the relay is shot.

If the relay is okay and your A/C is off, it looks like the temp sensor is shot.


#6

I’m with you guys . . . hey OP . . . which fan are you talking about? Rocketman