'02 Yukon Denali XL.
There is a noise that is coming from the AC compressor area of the motor, but don't know if its that, or another pulley. Best sound description I can compare it to is the typical ford whining steering punp, the whining increases with engine speed until it cuts out.
It doesn't always make the noise. I might hear it most times when accelerating or at idle for several days, then it will disappear, and won't hear it for several, then it comes back. The AC is blowing out cold air. The noise, at least at idle, starts when the AC compressor kicks on, and sometimes will stop once it shuts off, other times it keeps making the noise
Any ideas?