Whistling Noise

[davidholland]

On my 03 Explorer 4.0 v6,when cold it seems to have an audible whistle.any thoughts as to what this could be? It has just turned 63K. I'm thinking maybe serpentine belt?

[cyclopsram]

My 2000 GM whistles when it is cold and I traced it to a lazy IAC. If the noise is related to the Snake Belt, it is commonly referred to as a squeal as in Oinker.

[Dragcity]

Yeah, when cold my car whistles at medium RPM. So the IAC you say? Does sound like an air intake thing, right in front of me.

[davidholland]

Forgive my ignorance,what is an IAC?

[Dragcity]

Idle Air Control. It's right next to the TPS silly.....(Throttle Positioning Sensor). These are two units connected to the Intake plenum, at the throttle body.....

Trying to figure out how the IAC lends itself to making so much noise.?