Loud Fan Noise/Whine

[SilverSL2012]

So it does have an electric fan in there! OP I can get you video of mine if you like. I can get it to do it on demand. It is pretty loud. Sounds like its moving a **** ton of air tho.

[fierari]

i think most of the cars today has it it turns on when the engine reaches a certain temp

[SilverSL2012]

Or A/C pressure also.

[Delta]

Originally Posted by fierari

i think most of the cars today has it it turns on when the engine reaches a certain temp

Yeah, it kicks on when it's extremely hot out. I've heard it kick in when it was 100* outside and idling in my driveway without the A/C even on.

[RoadDog66]

Cool, thanx guys. It was the first time I recall hearing it so it had me worried since we just put the truck through it's paces towing into PA. Appreciate the help.

[midocr]

So....why would my fan be running almost constantly even though the air temps have cooled down to and below the freezing mark? Is there a sensor that controls the fans? Location? My temp gauge never moves once it reaches temp, no matter what the outside temp is. Truck has 158k and trans/radiator bypass done.

[Skibane]

Originally Posted by midocr

So....why would my fan be running almost constantly even though the air temps have cooled down to and below the freezing mark? Is there a sensor that controls the fans?

IIRC, the engine computer uses the coolant temperature sensor to determine when the fan kicks on. Above a certain coolant temperature, the fan runs continuously, regardless of ambient air temperature or A/C settings.

If your fan clutch is slipping, it's possible that the coolant temperature could get high enough to turn on the electric fan. This can even happen in cold weather, if the truck isn't being driven fast enough to force sufficient air through the radiator.

[bob-w]

The service manual says that the ECU uses inputs from air cond and temperature sensors to determine when to turn on electric fan and determine HI or Low operation.