Incessant belt squeal at idle

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My daughter's car, 2004 Buick Lesabre 148K, runs like a top; I've changed serpentine belts numerous times, GM OEM #12569591, Goodyear Gatorback, Dayco, Bando, the old OEM belt back on....I have 5 belts, 4 of them less than 10K each. No matter which belt I use, it runs for awhile after being thoroughly warmed, then when you're idling like at a stoplight or in a drive thru, the belt starts howling like a banshee. It gets quiet upon slight acceleration, never a peep out of it on highway, etc.,A/C Compressor is good (per A/C only shop), water pump OEM new, belt tensioner new OEM, power steering pump smooth as butter....It's just aggravating. Tried belt dressing about 20K ago, no real help. Suggestions (other than dynamite) welcome.
 
Try soaking a new one overnight in 303. Not promising anything.

I use a big ziplock gallon bag and pour about a cup of 303 in with the belt. I flip it every now and then.
 
Infind the best thing to quiet a squeaky belt is a bit of talcum powder. Often belts are noisy due to a bit of oil or grease on the belt. The talc will absorb that oil.
 
Originally Posted by mightymousetech
Infind the best thing to quiet a squeaky belt is a bit of talcum powder. Often belts are noisy due to a bit of oil or grease on the belt. The talc will absorb that oil.


This sounds logical. Have you actually done it/worked?
 
Originally Posted by CatCam2
are you sure it isn't an idler pully??


I changed out the OEM belt tensioner with a new OEM belt tensioner. No difference....
 
Originally Posted by 2strokeNorthstar
A rusty pulley somewhere. I had an alternator pulley that was rusty/pitted and made me crazy. Swapping for new is the only thing that solved it.


I very much appreciate your thoughts; my pulleys are NOT rusty. Car has been garaged since new...
 
Originally Posted by clinebarger
Pulley misalignment? The power steering pulley is the biggest offender on GM cars & trucks especially if the pump has been changed.


Yeah, maybe a washer was missing or a bad part? Belts shouldn't go bad if everything is in alignment. Also did the OP check for play in all the pulleys with the belt off?
 
Originally Posted by Ihatetochangeoil
My daughter's car, 2004 Buick Lesabre 148K, runs like a top; I've changed serpentine belts numerous times, GM OEM #12569591, Goodyear Gatorback, Dayco, Bando, the old OEM belt back on....I have 5 belts, 4 of them less than 10K each. No matter which belt I use, it runs for awhile after being thoroughly warmed, then when you're idling like at a stoplight or in a drive thru, the belt starts howling like a banshee. It gets quiet upon slight acceleration, never a peep out of it on highway, etc.,A/C Compressor is good (per A/C only shop), water pump OEM new, belt tensioner new OEM, power steering pump smooth as butter....It's just aggravating. Tried belt dressing about 20K ago, no real help. Suggestions (other than dynamite) welcome.


You didnt list idler pulley.

Also you could suspect the belt tensioner... even though it is OEM.. every OEM one you buy may have a weak or sticky spring.

Try a different brand tensioner.

You shouldnt have to use any products on a serpentine.. you have a mechanical issue.
 
With the belt off, spin each pulley and see if you can feel any roughness or hear any noise. I've had a water pump that had some noise, changed it out, and the squeal was gone.
 
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Mine on my Buick wagon turned out to be an issue with the harmonic balancer going bad. We finally have peace and quiet after a few years of squealing that I could not get to go away. The harmonic balancer finally got bad enough it was obvious it needed replacing before it fell apart.
 
Originally Posted by WishIhadatruck
Mine on my Buick wagon turned out to be an issue with the harmonic balancer going bad. We finally have peace and quiet after a few years of squealing that I could not get to go away. The harmonic balancer finally got bad enough it was obvious it needed replacing before it fell apart.

Yes, this happened on my old Accord. The rubber between the two pieces of the balancer debonded and one part would move against the other. It sounded like belt squeal but all belts were new and properly tensioned.
 
Reminds me of pickup I had with a 350. It would squeak at idle that was annoying except if it rained, then it was deafening. It would destroy the smooth side of the belt in a few thousand miles. Wore a groove in the steel water pump pulley. Multiple trips to the dealer, replaced a bunch of stuff.
Turned out to be the power steering pulley being out of alignment. Dealer pulled it off and replaced it, never squeaked again.
 
Originally Posted by Oily_Thing
The grooves in the pulleys are worn out. You may need to replace the pulleys and install another new belt.

Or clean them, I have seen some pretty heavy deposits in the grooves as well.
 
In the past Toyota I owned, the Mitsuboshi (yes with an "o" as supposed to an "i" in car brand) belt has been doing the best in terms of squealing.

I am not sure if they made it for GM but I know the part no. is actually the belt nominal length.
So, in theory, if the belt are the same length or part no, then it should fit.

There is no guarantee that it works for your car, though especially if the squeal is not caused by the belt.
 
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