Whine coming from engine bay at idle..

[NJB]

Changes slightly with RPM's

Sounds like it MAY be coming from behind the timing cover.

Has about 110k miles. Timing belt has already been replaced once.

Any ideas?

UPDATE:

Haven't really had a chance to investigate further but here's an update.

It ony makes the whine at low RPM's while the truck is stationary. After I'm up and driving the sound goes away.

As I'm coming to a stop the whine comes back just before idle and it is in full force while the truck is stopped and idling.

I can almost feel a very light harmonic vibration that moves under my feet as I hear this sound.

Any guesses with this new info?

 

[fishrod]

That would be a tight (or loose) belt wouldnt it? mMaybe timing belt?

 

[4boer]

Alternaters have been known to whine. On GM's at least.