My 2002 WRX (stock 198K) began making a whine/howl at idle. As I suspected, the noise was coming from the front of the engine. To me it sounds like it's coming from the crank pulley, but it's hard to pin down (I plan to get a stethescope tomorrow).
I removed the covers on the timing belt to look in there, but didn't see anything too fishy... There is a small amount of some very fine aluminum shavings in the top pulley on the driver's side, but I can't imagine whatever is howling could have made them. Seems like they could have been there since new...Any thoughts?
I then began loosening belts in order to see if I could relieve stress on the pulleys and find/eliminate the noise... Well, when I loosened the front belt (Crank/AC/Idler) the noise was gone. Could it be the AC? Idler? Can anyone suggest a good way to diagnose which is the problem (since you can't just remove one of these without affecting the others)?
I don't know how the crank could make this noise, but maybe it could? Also, turning the AC on and off made little difference.
I appreciate anyone's suggestions on this; thanks in advance!