That #$%^ serpentine belt chirp again!

DrCharles

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I thought I'd fixed it for good about 3-4K miles ago... my '93 has the "good" (shock) tensioner installed, but both the idler and the tensioner pulleys needed new bearings so I replaced them. Also a new 111.5" belt which was difficult to put on without partially unbolting the alternator, but ended up in the proper tensioner range.

The truck is only used infrequently so this was done three years ago. Recently it started chirping again, first on decel but got steadily worse until it squeaked all the time. I sprayed some carb cleaner on the back side of the belt and it stopped immediately. But the next day the noise was back!

This picture shows how the belt has always run slightly forward on the idler pulley. I just checked and there is no slop in either bearing. I think the belt has stretched with time so that the tension is less. Should I just replace the belt and see how long that lasts, or maybe go to the next shorter one assuming I could even get it on?

I've read many belt chirp threads here and on other IDI sites. No one solution seems to always be correct... any help appreciated.
 

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Big Bart

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Try a Gates green industrial belt. Also look for something else like a power steering pump, a/c clutch bearing, water pump, etc that is not turning easily. Your belt may be squealing because something is not wanting to turn properly.
 

DrCharles

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Thanks :) Hard to find anything except what Autozone and O'Reilly carry (unless I mail-order of course).
Also components I replaced are: water pump, a/c compressor and clutch, alternator and vacuum pump... this truck had been really neglected when I bought it!
Not much left except p/s pump...
 

Big Bart

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O’Rielly’s can order them in.

Also never assume a new/rebuilt part is any good. Story after story on this site of parts that are bad out of the box or failed shortly after.

One other thought, do your pulleys all line up? Perhaps The belt is sliding on your smooth pulley’s to move over for the next pulley that sticks further in or out. Thus chirping?
 

DrCharles

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I've looked pretty closely at the pulley alignment and they seem to be ok. Just the idler wants to run near the edge.

I have also read about out-of-round vacuum pump pulleys causing the chirp, but to a finger I can't detect significant runout.

Unfortunately I have had my experiences with parts bad-in-the-box but mostly from Autozone. I tend to buy from O'Reilly when I can.

BTW Autozone says the 110.5 is correct for my truck, not the 111.5... might be interesting to get a new one on though!
 

The_Josh_Bear

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I thought I'd fixed it for good about 3-4K miles ago... my '93 has the "good" (shock) tensioner installed, but both the idler and the tensioner pulleys needed new bearings so I replaced them. Also a new 111.5" belt which was difficult to put on without partially unbolting the alternator, but ended up in the proper tensioner range.

The truck is only used infrequently so this was done three years ago. Recently it started chirping again, first on decel but got steadily worse until it squeaked all the time. I sprayed some carb cleaner on the back side of the belt and it stopped immediately. But the next day the noise was back!

This picture shows how the belt has always run slightly forward on the idler pulley. I just checked and there is no slop in either bearing. I think the belt has stretched with time so that the tension is less. Should I just replace the belt and see how long that lasts, or maybe go to the next shorter one assuming I could even get it on?

I've read many belt chirp threads here and on other IDI sites. No one solution seems to always be correct... any help appreciated.
We had a Corolla that had some form of serpentine noise at the tensioner and the approved internet fix was a one size shorter belt. Gates was the brand and I've found Gates to be superb over the last 10 years or so. They are doing really good work in a system that generally has supplanted quality for cheap and easy.

Another thought is that NAPA makes a wax stick for belts. Works very good, just apply to the back of the belt with engine running, and don't get your shirt sleeve get caught doing it!
 

Clb

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Just a thought....
Having sat for a long period of time things get stiff and pissy, perhaps take it out and get it hot and sweaty...
 

ttman4

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Another thought is that NAPA makes a wax stick for belts. Works very good, just apply to the back of the belt with engine running, and don't get your shirt sleeve get caught doing it!
I have used a bar of soap on the belt while running and quietens down. Old mechanic showed me that trick. If something else going on & noise/squeaking keeps coming back then look other things over.
BTW before you use soap call yo insurance lady & insure your fingers one at a time..... that way when you loose 1-2-3 fingers you can collect on each one. LOL LOL
 

DrCharles

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As I mentioned earlier, a quick spray of carb cleaner on the back side of the belt immediately stopped the chirping. Started again the next day, though.
So I got a 110.5 belt and it's quiet so far. It's the next size down from the 111.5 I had on there, and even with the tensioner all the way loose, I still had to partially dismount the alternator to get it on. Worth the extra couple of minutes if it will stay quiet!
 

Slicknik

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carb cleaner is only a temporary fix, IF your belt is under the correct amount of tension then look at the pulleys themselves. take the belt off and check each pulley to make sure is spins freely , sometimes its just a bad pulley on one of the accessories(alt/waterpump/AC/idler/tensioner. Mine ended up chirping randomly on the decel ended up being the alternator pulley was going out and finally gave up and locked up in the middle of an intersection. The trick of running a shorter belts works in the short run but will eventually stretch out and could start making a chirp noise again.
 

cozinsky

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I battled the same problem several years ago on mine. The fix was a Goodyear Gatorback belt. They have staggered cuts in the belt, similar to tire tread that cancels out the noise. I've never had even a chirp from it since.
Edit: Looks like they've been discontinued. Oh well...
 
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lotzagoodstuff

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Goodyear Gatorback was my favorite belt. Nowadays I follow the advice of Mr. Towcat: Gates Fleetrunner belts. If you order them online, they really aren't that much more expensive.
 

Kizer

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I fixed the chirp by cleaning the pulleys with brake cleaner and a wire brush.
 

ttman4

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carb cleaner is only a temporary fix, IF your belt is under the correct amount of tension then look at the pulleys themselves. take the belt off and check each pulley to make sure is spins freely , sometimes its just a bad pulley on one of the accessories(alt/waterpump/AC/idler/tensioner. Mine ended up chirping randomly on the decel ended up being the alternator pulley was going out and finally gave up and locked up in the middle of an intersection. The trick of running a shorter belts works in the short run but will eventually stretch out and could start making a chirp noise again.
Few months ago mine was chirping/squealing off & on & I was using the bar soap trick. Turned out I had a bad IDLER PULLY. When I down shifted things let go. Threw the fan belt, spun my fan clutch off (cause I'd stupidly used anti-seize) and fan got into the radiator. Had to pull radiator & fix, replace everything.
Soap trick stops squeal etc, but if keeps on as @Slicknik says it only temporary.
 
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