AAHTahoe

I live in the Phoenix, AZ area and have noticed that at any time of day or night,the radiator fan comes on just after starting the truck. The truck has been sitting in a garage. I have not noticed how long it runs since I am concentrating on driving safely at that point. Any feedback is greatly appreciated. Thx.

ZX1100F1

At least one of the fans (there are two) will always be on when the A/C is on.

AAHTahoe

Thank you - that helps a lot. I usually turn on the fan a few notches and hit the recirculate button just before backing out of the garage.

e

damn things are loud too...... Mine come after start up as well.

autopromo

I also live in phx.. I have the same thing on my yukon

Rich2007Z71

Not to show my mechanical ignorance, but, when running my A/C at a high level, or if I used the remote start when the A/C is blasting, it sounds like my engine is going to blow up!!! It sounds like it is really revving, so I am wondering if this is the radiator fan? Specs - '07 LT3 Z71.

Thanks.

AAHTahoe

Anyone know if there is a tempature gauge in play here? My Tahoe can sit in the garage over night and one of the two fans will come on after starting it and putting it in gear. I will add here that the past few weeks it has been 85 degrees at 5:00am in PHX and probably 10 degrees warmer in the garage. I agree with the other poster who mentioned that it sounds like it's going to blow up.

ZX1100F1

The sound is the engine cooling fans and it is normal, there are two fans and they each can operate in either low or high speed, they are controlled by the computer and there are several factors and parameters that determine which fan(s) and what speed they are to be turned on, one of which is the engine coolant temperature the other is the A/C system.

The fan(s) are operating when the A/C is on to pull air through the Air Conditioner Condenser which is located just in front of the radiator, by pulling cool air through the condenser it cools the refrigerant in the system which enhances the A/C’s ability to cool the cabin.
The fans are high flow units and when in the high speed mode they are fairly loud but the noise should not be audible inside the vehicle.

Rich2007Z71

Thanks ZX, I knew you would know the answer. Not to date myself, but you remind me of the Shell Answer Man. j/k and thanks for all the great answers and help.