Got uid0

Why would you spray silicon on a belt?

You are going to cause slippage or a thrown belt.

The C5 Tensioner pulleys or Harmonic balancer is known cause of the squeeks.


IF your balancer is not running true and you can see the grooves shaking around you have a failing harmonic balancer that need replacement asap before you have bigger problems.

Got uid0

Remove one belt at a time and see where the problem is first.

CMC Corvette

I saw that so many of you had success with the Goodyear Gatorback belts that I got one (the main belt; stock # ends in 798) and put it on my 2001 5.7L. THE NOISE IS GONE; HOWEVER---- While replacing the belt, I noticed that as I would release and apply the belt tension on the main tensioner pulley (top of engine, passenger side), that the pulley would turn slightly sideways. (Tension off, the pulley would be straight; tension on, the pulley would go slightly sideways again.) Even though the new belt eliminated the squeak/squeal, I am convinced that the pulley was the main problem and I did not want a pulley out of line. I have just replaced the tensioner/pulley ($40 for the part). It took me less than 10 minutes to get the belt off, unscrew the two tensioner/pulley bolts and remove, and replace with the new tensioner. I've got a total of $60 in the belt and tensioner/pulley.

JWhitcher

Thanks for the great post.

I just fixed my belt/pulley issues.

Rather than buy new pulleys I cleaned and greased them. I then replaced both belts. The main belt didn't look too bad but the A/C belt had a few cracks on the ribbed side.

I got the belts from Pep Boys. Standard issue Dayco belts.

Dayco 5060800 Serpentine Main Belt $28.99
Dayco 5040420 Serpentine A/C Belt $19.99

They were a few bucks more than Amazon but worth the instant gratification.

The whole job took about 2 hours including the trip to Pep Boys.

Jeremy

Corvettewaldon

I just went through this last weekend.
Quick check to see if belts, spray inside of belt with water, if squeal goes away for a sec, bad belt. I ended up replacing drive belt and tension pulley, squeal still there. Changes air belt and both pulleys...all better! man that noise drove me crazy...was easy fix, just PITA getting ac belt and pulleys off and on.....
:will y:

Corvettewaldon

for me, the new pulley's were only couple bucks more than the proper grease...so I opted for new. I did see a video for cleaning and repacking...

Eric Sr

So many different possible reasons for belt or pulley noises and you've already replaced the belts I just wanted to throw this in as a side note as a means of tracking down possible belt squeal, with motor running I took a small wire brush that has similar size and shape of a tooth brush and applied it to the outer (smooth) side of the AC belt, squeal went away telling me the belt needed to be replaced. Just a quick test to hopefully eliminate guess work and save some money

KGoodwin

On a 2000 C5 Coupe with Automatic Transmission, I replaced the entire AC Drive Belt system (Idler Pulley ACDelco GM # 15-4669 $33, Tensioner ACDelco GM # 12560345 $67, Goodyear Gatorback Belt #4040420 $8). After many hours of attempting different installation schemes, my conclusion was that it was a two person task - one working the tensioner from underneath (15 mm long handle wrench) while an associate strong armed the installation of the new belt. One critical hint: remove the transmission coolant lines hold down fixture that is in front of the oil filter along with the clip between the two lines that is just in front of the idler pulley since moving the tensioner to allow installation of the new belt will impart a significant force to these damn coolant lines. Removing the coolant lines hold down fixture (10 mm bolt) will decrease the odds of bending/breaking the transmission coolant (metal) lines. I did find the recommended 50 NM torque setting for the pulley and tensioner bolts to be unsettling high. Make sure you note the idler pulley washer/dust shield parts placement on the old items or you'll find the pulley won't rotate after incorrectly installing it. For basic installation instructions, Shop Manual Volume 2 pages 6-54 thru 6-62. For us automatic transmission operators who have to work around the transmission coolant lines, this entire job is one PITA, especially compared to the accessory belt. The AC belt system squeeks got bad after 50K miles/16 years having earlier replaced the belts at 25K miles/7 years.

Theo Kort

$$$$$$$ my ac pullet squealed when the ac turn on and there was a nick on the pulley grooves for the belt that was causing the belt to move back and forth. I took a rat file and filed the nick smooth and it stopped squealing (the nick was not under the belt and i doubt the pulley can get a nick under the belt)

SuperTom

Look down at your harmonic balancer if that is starting to wobble it will make your belts squeal.

maiorka2

Does anyone know what tensioner pulley I need for my 1990 C4? I think the wrong ones on it I’m getting pretty frustrated.

Smoken1

You might want to ask a mod to move your post to the C4 section

maiorka2

sorry still learning how to get around on here

grinder11

When you do learn to "get around," you might also try to avoid 6 year old threads, and start your own. Just trying to help, and welcome to the forum....