Belt Chirp Troubleshooting
 

My belt has been squeaking/chirping. It doesn't seem to do it when cold. I have replaced the serpentine belt. Noise goes away when I have sprayed a small amount of silicon spray but it returned shortly thereafter. My a/c b elt is in rough shape and my mechanic thinks that may be the issue but I'm not sure if that belt moves unless the ac is engaged. Noise does not go away when a/c is engaged. I'm thinking it has to be a pulley issue. Any thoughts? Anyone familiar with this issue to contribute to my troubleshooting? Thanks?

Could still be the other belt. Change that one too.

If that doesn't help then I would start looking into pulley problems.

I'd take a mechanic's stethoscope and figure out which pulley the noise is coming from. Then take it from there.

Ed

The A/C belt is crank driven just like the main sperp belt, and is spinning at all times, so that could very likely be your problem. If not, you could have a defective belt tensioner.

Replaced A/C belt to no avail and the sound continues. I'll have to bring it back in, interested in seeing what It is. It goes away when I've sprayed some silicone spray on it but returns shortly later. I had the main belt tensioner replaced in Sep. 2009 so I don't think it is the tensioner. Must be an idler pulley but I obviously feel like I'm shooting in the dark

Have you changed anything else that runs on that belt? Mainly I was wondering about the alternator.

The alternator was replaced with a used BMW one not that long ago. it is possible the pulley on the alternator is bad? Sure doesn't seem to be a belt issue.

It's possible but one of the guys had replaced his alternator and the one he bought from Advance caused the belt to come out slightly and caused a whine similar to yours. Same thing with the lubricant, if you have the old alternator measure distance from base to belt track, the. On new one and see if there's a difference? A long shot but possible.

Or just do what I suggested and know for certain what is making the noise.

Your call.

True. Sorry Ed, missed that post.

:)