Pulling out my hair trying to find out why the belt squeals ONLY at an idle and only sometimes (lasts only for about 3 seconds). A little background info, took the car in for:
* 2.49 S/C'er pulley,
* Idler pulley (larger to fit the new smaller s/c'er pulley)
* Killer chiller install (probably irrelevant but throwing it out there anyways) *Catch can
*Dyno tune.
Prior to all this I never had this squealing but now when I get to a light, only sometimes, I'll get this high pitch squeal. When popping the hood I noticed there was oil or something similar all over the belt and under the S/C'er so our first thought was the bearing were bad in the S/C'er and it was leaking from the snout. After Engine degreasing everything and wiping the belt down, I haven't noticed anymore fluids flung all over the place and seems to be pretty dry. The thought is maybe the shop used belt dressing when doing all those installs listed above but still doesn't answer why is squealed with the belt dressing and now that its mostly all cleaned off. Also, the belt is still in great condition, all ribs are intact and doesn't seem to be worn whatsoever.

 

How is the tension? It could be getting stretched out a bit but then I think it would slip/squeal during shifting.

Check and see if all of your accessory pulleys spin freely. You can always try an old school trick. Take a dab of rtv silicone adhesive and put a dab on the ribs in a couple of spots and then run the motor for a few minutes. It is only a temporary fix but it's quick and easy.

 

Tension is tight, The only thing i noticed is that on the side of the belt it seems like it might be wearing due to possibly rubbing but would that make the noise. Its never squeal'ed while moving or shifting for whatever reason.

 

Look around your pulleys and you should see some belt/rubber dust built up where it is rubbing. That would be my #1 suspect for the squealing. Check and see if any of your pulleys have any wobble from worn bearings. I know I have replaced idles a few times and now have a billet set I'm getting ready to put on.

As I was thinking about this I was finding it odd that it only did it at idle and here are my thoughts. At idle the belt is not moving with much force or velocity. I'm thinking that there is something hanging up that won't spin when it's at idle but once the belt picks up speed and force becomes greater, it becomes a non-issue. That would mean an alternator or PS pump or whatever is not spinning as it should or takes just a little more force to spin it.

 

That's a good point about something hanging up, haven't thought of that.

 

I got some oil on my belt one time and even though I thought cleaned it off completely it still squealed. It's been years and I don't remember for sure, but it seems like it was at idle. I finally had to replace the belt to get it stop, you might give that a try. If it doesn't help you'll have a spare belt.

 

On my Saleen blower a Gateway belt squeal like hell. I tryed a Goodyear Gaterback belt and never looked back.

 

A little bit of RTV usually stops the squeal. Just a dab on your finger on both sides the belt will usually do the trick. Crank it up as soon as you dab the RTV. Don't let it dry. The Goodyear belts suck. Actually the auto zone dayco belts squeal less than goodyears.

 

Appreciate it, I'll be back in town tomorrow and i'll mess with it a bit. I hope I can just get away with a new belt.