When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Hello everyone, so I'm hearing high pitched squeaking from under the hood at ~10%-40% throttle, sometimes also squeaks on cold start. The belts are GM belts replaced 3 years ago with 4000 miles on them, am I right in thinking the drive belt tensioner needs replaced? It's very annoying as the throttle from cruise control is enough to make it squeak, the only time it goes away is if I'm idling or really getting on it. The dealership said it could be the belts but they didn't know the belts were replaced 4k miles ago, I'd rather not spend the $190 on belts it doesn't need if it just needs the $120 tensioner.
You just described the symptoms my car had and I had the idler pulley, tensioner and harmonic balancer replaced with an ATI balancer. Took care of all my issues.
You just described the symptoms my car had and I had the idler pulley, tensioner and harmonic balancer replaced with an ATI balancer. Took care of all my issues.
Thanks for the info, looks like I'm just going to have to deal with it for another month until I can free up the cash to replace the items that could cause it.
I still have my original idlers. That said, I bought my car under the 'lemon law'! This is interesting, at least to me it was. I'm the "original owner". BUT-Car had 23,000 miles on it when I bought it. Someone had leased this car new. Therefore, he was the "original leasee", and I'm the "original owner"! Talk about a dealer splitting hairs! After 2 years, he apparently lost his job. So he tried to say the accessory drive system made a constant squealing. He returned the car at least 12 times (I ran the VIN!), finally claiming he got a "lemon". This is how he got out of the deal without damaging his credit. My car is still silent with the same idlers/tensioners it had almost 18 years ago! The ONLY time you can hear any very slight chirping is when you turn on the A/C. Can't hear it with the top up. Barely hear it with the top down, but you don't really need A/C with the top down, so there's zero belt noise top down OR top up........
St. Jude Donor '14-'15-'16-'17-'18-'19-'20-'21-'22-'23
Originally Posted by grinder11
I still have my original idlers. That said, I bought my car under the 'lemon law'! This is interesting, at least to me it was. I'm the "original owner". BUT-Car had 23,000 miles on it when I bought it. Someone had leased this car new. Therefore, he was the "original leasee", and I'm the "original owner"! Talk about a dealer splitting hairs! After 2 years, he apparently lost his job. So he tried to say the accessory drive system made a constant squealing. He returned the car at least 12 times (I ran the VIN!), finally claiming he got a "lemon". This is how he got out of the deal without damaging his credit. My car is still silent with the same idlers/tensioners it had almost 18 years ago! The ONLY time you can hear any very slight chirping is when you turn on the A/C. Can't hear it with the top up. Barely hear it with the top down, but you don't really need A/C with the top down, so there's zero belt noise top down OR top up........
So your saying your LS7 uses the same pulleys as a LS1/LS6?
Spray some water on the belts, if the sound dissapears then it is the belt/s. If it isn't one of the belts take off the belts and spin the pulleys, if some of them spins freely, that means the bearing is completely dry. And you either have to replace the pulley or you can pop the dust cover and pack the bearing up with some wheel bearing grease, this works very well and you won't have to buy new pulleys. Obviously one of the pulleys could also be very hard to spin, then you can do the same procedure of adding fresh grease in the bearing.
I've done this to some of my pulleys that made a squeaking sound, and it has worked well.
If you see excessive "bouncing" from the belt tensioner this has to be replaced. If it doesn't move much that isn't your problem either.
If you don't find any of the pulleys to be bad, nor the belts, then it could be the infamous harmonic balancer, check that for wobble aswell. You can even draw a line from the inner part of the balancer to the outer part, and if this line doesn't line up after running for a bit, then you would have to look into replacing the harmonic balancer.
Good luck, this seems like to be a problem that every c5 owner will get into.
Spray some water on the belts, if the sound dissapears then it is the belt/s. If it isn't one of the belts take off the belts and spin the pulleys, if some of them spins freely, that means the bearing is completely dry. And you either have to replace the pulley or you can pop the dust cover and pack the bearing up with some wheel bearing grease, this works very well and you won't have to buy new pulleys. Obviously one of the pulleys could also be very hard to spin, then you can do the same procedure of adding fresh grease in the bearing.
I've done this to some of my pulleys that made a squeaking sound, and it has worked well.
If you see excessive "bouncing" from the belt tensioner this has to be replaced. If it doesn't move much that isn't your problem either.
If you don't find any of the pulleys to be bad, nor the belts, then it could be the infamous harmonic balancer, check that for wobble aswell. You can even draw a line from the inner part of the balancer to the outer part, and if this line doesn't line up after running for a bit, then you would have to look into replacing the harmonic balancer.
Good luck, this seems like to be a problem that every c5 owner will get into.
03-29-2021, 05:40 PM
Belt Noise Diagnosis
