OK, so I noticed a VERY minor squeaking coming from the serpentine belt on my 98 Blazer LT. After inspecting the old belt, I decided to go ahead and change it. The old one was the Gaterback but they do not sell it at my local Oreilly's, so I just got the $27 belt they had. When I first started it up after replacing the belt, it was silent. However after about 3 miles of driving it started squealing pretty good. I went up to Oreilly's and they thought maybe I had got a defective belt. The guy handed me another of the exact same belt and I switched them out right there in the parking lot. Again no noise at all until I drove for a few miles! While in idle, it makes no noise, but as soon as you touch the gas, it squeals. But, if I kinda get on it a bit and hit about 3000 rpm it stops squeaking and it will not squeak again at any speed until the motor has been turned off. Once it is turned off, and then re-started it starts squeaking all over again! I tried some belt conditioner spray, not really any help. I am thinking maybe the idler pulley (the smooth pulley between the alternator and a/c compressor) might be going bad. I can wiggle it a little bit even though the bolt is tight, and the squeaking noise seems to be coming from that pulley. Any body have any suggestions? Any old Chevy tricks or anything I should know? I REALLY appreciate any help, and thank you very much!

 

Yeah... Go to Goodyear store and order a gatorback. Or from rockauto.

You probably been bit by the Dayco syndrome. No. it does not matter what the brand label sez.

Then before you change the belt, take mineral spirits or lacquer thinner and wipe down ALL the smooth pulleys.
Another cause MAY be that you have a weak tensioner.
However we have a whole BUNCH of this problem on here a couple months ago. Almost all of us, the problem fixed by gatorback.

The squeaking is actually the back of the belt pulling off the water pump pulley. Same like when you pull scotch tape off the roll.

 

The old belt was a gatorback, and it also was squeaking. Not quite as loudly, but it was squeaking. Also, the fact that EVERY time I hit a certain rpm it instantly stops and is perfectly silent no matter how slow or fast I go, until the engine is shut off there is absolutely NO squeaking at all. Then even if the motor is only off for just a minute or two, it squeaks again until I hit that certain rpm, then it is silent again! If I start it up and drive around town it will squeak for hours if I don't hit that certain rpm. That tells me it isn't necessarily the temp. of the belt making the difference, it is the speed.The tensioner does have a very small amount of movement while the engine is running, but it does seem to still have alot of strength to it. When changing the belt it took ALOT of strength to move it enough to get the new belt on!

 

Then look at your pulleys and make sure they are in line. esp power steering. Or maybe it isnt belt anyway... could be the AC pulley bearing

https://www.google.com/search?q=belt...lazerforum.com

Dayco can divert blame all they want.. it's their compound that is the problem

https://www.google.com/search?q=belt...the+time+dayco

 

+1 on the gatorback. I had a gates "heavy duty" belt that squealed. Went to gatorback and its been quiet for the last 8k miles.

 

do the pulleys anyway... might as well unless the truck has new ones already... i did mine... it was cheap and easy and i dont have to think about it for a while... peice of mind

 

The belt I bought is a MasterPro. I am just baffled by the fact that it stops at the exact same point every time. As of 1 week ago it had NEVER squealed, and absolutely nothing has happened as far as any pulleys being moved or messed with at all. No oil or antifreeze leaks. No impact or any way for anything to jar loose so I am not sure how any pulleys could be out of alignment. I am pretty positive the sound emanates from the idler pulley, so for only $13.99 I will buy a new one and see if that is it. I really do appreciate all the input though. Many opinions are always better to consider than just your own!!!!

 

Another possibility: if the battery is weak, the alternator could be adding drag tying to charge the battery up after you start the engine. It's possible that once the battery is charged, no more squeal. The combination of that, and a weak tensioner, could be the cause. Might be worthwhile to load test the battery and check alternator output, (on the vehicle) just after a restart. Pay close attention to alternator output and see if it's related to the squeal.