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Need some help.. maybe someone know exactly what this is. I have an issue where the belt/pulley is squealing...
2009 C6 Corvette LS3.
Cam recently Installed and working on tune.
All of the pulleys, pumps, etc that part of the accessory drive are OEM. EDIT: Except for PB1117SS PowerBond balancer.
Behavior-
Belt/pulley begins squealing around ~100 degrees, but does not from cold start.
Whether the car is warm or cold.. If the belts are removed.. then the noise disappears.
The noise is present if the serpentine belt is on and A/C belt is off
The noise is NOT present if the serpentine belt is removed.. even if the car is warm.
What I have tried so far-
Spun all pulleys by hand and the alternator pulley seemed to be making some noise and was visible moving some. I replaced the alternator with a new OEM one. Same behavior as above.
Removed and cleaned the tensioner idler pulley - Bearing seemed fine just a bit dirty. Same behavior as above.
Also tried removing air filter and inspecting intake track.. but this made no difference.
Additional thoughts -
Is there something that happens around 100 - 105 degrees that I am not thinking of? Water pump? Power steering pump? Thermostat?
I wouldn't think any of this would be effected by such a low temp.. but not 100%.
Also.. I have new belts arriving tomorrow.. although I don't think it will make much difference.
Any help would be greatly appreciated.
Last edited by DallasVetteGuy; Sep 28, 2021 at 08:59 PM.
No. I will double check though. Your post reminded me that I replaced the balancer with the PB1117SS PowerBond balancer instead of the factory OEM as I stated above. I wouldn't think this would cause this issue unless it maybe related to alignment of the balancer.. but again it should do it all the time if the balancer were loose or mis aligned.
Edited original post as well.
Last edited by DallasVetteGuy; Sep 28, 2021 at 09:00 PM.
I am assuming that you have ruled out the idler pulleys as they are pretty easy to access and diagnose. The only two items I can think of is the power steering pump and the water pump. Both of those operate under pressure and heat is involved with both. Have you moved the steering wheel back and forth from stop to stop to see if the sound changes? Check underneath the water pump as there should be a weep hole in the pulley housing where fluid will drip or leak from as an indication of bearing failure.
That's all I can think of that you haven't mentioned. Good luck & let us know what you find?
The first thing I thought if was the top tensioner, as I had one that squeaked after changing out the water pump. I removed it, removed the bearing seal cap, and pumped it full of grease and put it back together and noise disappeared. I was going to buy a new tensioner, but the one I refilled with grease has worked flawlessly for 80,000 miles since then.
The same can be done with the A/C tensioner, and the idler bearing as well.
You can try regreasing, and if that solves the noise, you can buy new components if you feel more confident. You tube videos for doing these.
In your case.. did the pulley squeal all the time or only under certain conditions?
It was hit and miss, sometime cold, sometimes hot. There was minimal grease in the tensioner bearing race. I was surprised. Initially, since I had just replaced the water pump, I was thinking I had purchased a faulty pump. I was pretty happy that I tried the grease for the tensioner, but I was prepared to do the A/C tensioner as well. I had used a mechanical stethoscope to try to pinpoint the noise but mechnical noise travels over a wide range, but it seemed to be at the top, which it was.
I think I figured it out.. Im not 100% on which of these it was.. but the noise seems to be gone.
Did a visual inspection of the water pump and power steering pump for alignment or leaks. None found
Next I pulled both idler bearing and greased as suggested above. While the bearings seemed in need of grease.. this didn't make a difference for this noise.
After some more research I saw a tip about using water or something that would temporarily make the belt wet. The idea here is that a dry belt can rub and/or walk on the pulleys creating squealing. I started with the outside of the belt which made no difference.
Then I pulled the belt back off and was looking at the belt alignment and pulleys again and noticed... The inside of the belt and some of the pulleys were dirty.. I did a full wipe down on all pulleys and the inside of the belt. I also applied a little Mother's VLR, which conditions Vinyl, leather and rubber, and the reinstalled and made sure the alignment was right. (Also have a new belt on the way)
No noise.
Unless it comes back.. It seems like it was a combination of cleaning, aligning, and conditioning the belt and pulleys.. Go figure...
Last edited by DallasVetteGuy; Sep 29, 2021 at 07:16 PM.
Squealing belt/pulley help
