Belt squeel or something else?
Thread Starter
Cruising
Joined: Feb 2009
Posts: 12
Likes: 0
From: Olympia WA
Belt squeel or something else?
1999 FRC, stock other than Blackwing air intake. I'm getting what sounds like a belt squeel. It won't make any noise when free revving the engine, it only makes noise while underway, typically under light to moderate acceleration. I don't hear it under hard acceleration. I installed new Gatorback belts, and spun everything by hand with the belts off and didn't notice anything strange. I can't afford to start replacing parts not really knowing where the noise is coming from. I can't think of anything else on the car that would make this noise though. Other than driving the car down the road with no belts on at all I'm not sure what else to do to try to pinpoint the noise. Any ideas would be appreciated.
Burning Brakes
Joined: Sep 2003
Posts: 1,085
Likes: 0
From: Broken Arrow OK
The A/C belt will cause this problem. It is usually associated with coolant, from the water pump, leaking onto the belt. Try spraying some silicone spray directly on the A/C belt, with the engine running. If it immediately quiets down, that is the problem.
Thread Starter
Cruising
Joined: Feb 2009
Posts: 12
Likes: 0
From: Olympia WA
It won't make the noise while the car is sitting with no real load, even revving it hard - it only does it while underway, and typically under light to moderate acceleration, and also sometimes a little noise under deceleration. If it would do it while I could stand there and spray the belt I would try that. I think the next best thing is just removing each belt at a time and drive it. If it still makes the noise with no belts I'll really be confused -
Racer
Joined: Nov 2008
Posts: 378
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For what it's worth, my '99 coupe does not like Gatorbacks. I replaced the main drive with belt with a GB and after about 2 months of chasing this odd sound, I thought it was a bearing in the original alternator which was 10 years old. I went to AutoZone and bought a new one and switched it in the parking lot. Started up the car and there it was again! I kept the alternator because it was probably on it's last legs anyway. I was at wits ends trying to figure out where this noise was coming from. I had gone over everything on the car.
When I got home I immediately removed the GB belt and put on a new Dayco that I had on my shelf and bingo, the noise was gone. The GB's have a different tread pattern compared to the stock and Dayco belts, which may have been the problem.
I've also read on the this forum that GB's don't come in the exact size as the factory belts so either you have go with a little smaller or a little larger belt. I have no idea if my GB was larger or smaller than the original belt, but I do know that the noise is completely gone.
When I got home I immediately removed the GB belt and put on a new Dayco that I had on my shelf and bingo, the noise was gone. The GB's have a different tread pattern compared to the stock and Dayco belts, which may have been the problem.
I've also read on the this forum that GB's don't come in the exact size as the factory belts so either you have go with a little smaller or a little larger belt. I have no idea if my GB was larger or smaller than the original belt, but I do know that the noise is completely gone.
Advanced
Joined: Nov 2008
Posts: 80
Likes: 0
From: RACELAND KY
Belt noise
What about wobble on your bottom (h/b) pulley? Dealing with the same problem and I do have some wobble. Some people say wobble is normal?? I don't know!! Figure it out let us know. GOOD LUCK!
Drifting
Joined: Jan 2001
Posts: 1,347
Likes: 4
From: Slidell La
Correct. Most folks think it is the belt pulley on the ac tensioner that wears but it is the pivot bearing. There are 2 designs , early and of course late. This is a common problem. I just changed one and it really is a PITA to change. But the pivot bearing had worn so extreme it was about 10 degrees off center. This causes extra wear on the belt and will only squeek when the belt loads and unloads due to the design. I used a piece of 1" pvc pipe as an ear piece to listen to each pulley before I found the squeek in mine. Now it is quiet. Note if you use the new design get a new bolt for it as the bolt will not have the small shoulder the older one has. 
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Racer
Joined: Jun 2005
Posts: 438
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It's NOT normal operation, just a common C5 problem! I just went through this with my 2000 A4. The wobbling harmonic balancer was causing the belt to chirp when it was wet outside. The harmonic balancer can separate over time, if it goes, than you're looking at a lot of damage.
Thread Starter
Cruising
Joined: Feb 2009
Posts: 12
Likes: 0
From: Olympia WA
Thanks for everyones advice - I took off the belts and ran the engine, luckily for me it did something that it hasn't before - it made the noise while free revving it instead of having to drive it. So it's not belt related, although it really does sound like a belt or bearing type noise. It seems to be coming from under the car, it sounds like a strange exhaust noise, maybe metal touching metal somewhere. Hopefully it will make the noise while I have the car on stands & lay under it and have someone rev it so I can pinpoint the noise.
Pro
Joined: Aug 2005
Posts: 573
Likes: 0
Thanks for everyones advice - I took off the belts and ran the engine, luckily for me it did something that it hasn't before - it made the noise while free revving it instead of having to drive it. So it's not belt related, although it really does sound like a belt or bearing type noise. It seems to be coming from under the car, it sounds like a strange exhaust noise, maybe metal touching metal somewhere. Hopefully it will make the noise while I have the car on stands & lay under it and have someone rev it so I can pinpoint the noise.
I came across this post while researching a pulley problem and it may answer your noise.
http://forums.corvetteforum.com/c5-t...=idler+pulleye.