Ok, I'm about to crazy!
 

I have the ye olde belt whine.

I have replaced the tensioner, checked all the pulleys for noise or bad bearings, wire brushed all the pulleys, and put a new Dayco belt on, which by the way was on before I brushed the pulleys.

When I spray carb and choke cleaner on the belt when it's running, the noise instantly quits, but then returns a while later.

Is the Dayco belt a piece a junk? Should I go with a Gates belt?

Any help would be appreciated.

I've always had good luck with Goodyear Gatorback belts.

I use Gatorback. Get some belt dressing and see if a little shot shuts it up.

Yeah, I would head down to the auto parts store and pick up some belt dressing. I think the can is about $5 but it works good. It stopped the squeak on my sister in laws Sunfire!

Belt dressing didn't work on my truck, it still made noise.

Oh, wait, that was the alternator bearings.

n/m

Anyway, belt dressing will let you know if it is indeed the belt, but it wears off fast and the noise comes back. That's my experience anyway. I think the Gatorback for our trucks is about 30 bucks and they last nearly forever.

I've had intermittant belt noises too, but I noticed that it always acts up when the weather is especially humid, then gets better when it's not. My mechanic confirmed that his truck does this too. I don't know if that odd little fact will help you at all but hey, thought I'd share. Good luck!

Make sure the belt tensioner spring is free. Take the belt off and work the tensioner back and forth, to obtain full travel. Spray some PB in where the spring is.

Thanks for all the reply's, I'll try the Gatorback belt.

The tensioner tends to get stuck at a certain point of tension over the years. If you don't make sure it travels to it's full extent, you will have the same prob in a short period of time , no matter what brand belt you use.

you need a ac bypass pulley try omly spraying the clutch on your ac it will go away and come back 40 bucks at napa