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2007 with 49k. Had a slight chirp coming from front end, only during early am commutes (50-65 degrees). Had serpentine belt replaced, problem resolved. I'm now back to the issue again, only during colder days. Any suggestions?
If your balancer is not wobbling a lot, remove the pulleys and re-grease the bearings. Easy to do. Very little grease in those bearings from the factory. You don't have to buy new pulleys.
2007 with 49k. Had a slight chirp coming from front end, only during early am commutes (50-65 degrees). Had serpentine belt replaced, problem resolved. I'm now back to the issue again, only during colder days. Any suggestions?
Since the belt chirp returned after is went away, I suspect a misalignment of a pulley or a harmonic balancer with a wobble. Replacing the belt was a temporary fix until the misalignment caused the new belt to fray, thus chirp.
I would remove the belt and check the pulleys for play and dry bearings, including the tensioner. If everything checks out fine, check your HB for wobble.
I had the same belt chirp issue at cold start up that worsened. I installed a new belt, but the chirp returned after a week or so. I check all pulleys and tensioner all good. I replaced the HB that had a wobble with an ATI unit and no more chirp.
Last edited by Mike's LS3; 09-24-2016 at 11:49 PM.
Here is what I think. Corvettes have the same type balancer as other GM cars a rubber sleeve between two steel rings and have more problems. I think since Corvettes are parked for longer times, weeks to all winter that the belt tensioner pulls in one direction for long periods of time. Think of a flat spot on a tire that sits for weeks. When the car starts the balancer is untrue due to the pulling from the belt for however long it sits. After it warms up it also trues up but after time the rubber loses it's form and the ballancer is junk.
Here is what I think. Corvettes have the same type balancer as other GM cars a rubber sleeve between two steel rings and have more problems. I think since Corvettes are parked for longer times, weeks to all winter that the belt tensioner pulls in one direction for long periods of time. Think of a flat spot on a tire that sits for weeks. When the car starts the balancer is untrue due to the pulling from the belt for however long it sits. After it warms up it also trues up but after time the rubber loses it's form and the ballancer is junk.
No, not in my case on a weekly driven corvette. There's is an issue between the inner and outer ring seal. This is why I went with an ATI unit. The inner and outer shells bolt together. I also had it pinned to the crank.
No, not in my case on a weekly driven corvette. There's is an issue between the inner and outer ring seal. This is why I went with an ATI unit. The inner and outer shells bolt together. I also had it pinned to the crank.
this explains the real reason for the balancer issue, but as also mentioned, check the other pulleys, especially the idler and tensioner.
Proper alignment of all the pulleys and belt always important on any vehicle...........
The pulley on the HB bolts to the hub or the section that is inside of the rubber of the HB center section and is not effected by the tension of the belt.
It is the od of the HB that will separate from the hub and wobble.
The pulley on the HB bolts to the hub or the section that is inside of the rubber of the HB center section and is not effected by the tension of the belt.
It is the od of the HB that will separate from the hub and wobble.
Why does the belt chirp if the pulley is not part of the wobble? The belt drives off the outside of the balancer and when the rubber gets tired the pulley wobbles and the belt chirps.
Why does the belt chirp if the pulley is not part of the wobble? The belt drives off the outside of the balancer and when the rubber gets tired the pulley wobbles and the belt chirps.
I believe what 'Boilerman" is saying is that the inner ring/shell of the HB is bolted to the crank and will not wobble, unless the bolt backs off. The outer ring/shell of the HB will wobble when the seal between the inner and outer shell has failed. The failed seal causes the outer shell to rotate at a slight angle, thus causing belt misalignment.
It's like part of a bicycle tire bead not quite on the rim . The rim spins correctly, but the tire wobbles.
Last edited by Mike's LS3; 09-26-2016 at 11:53 AM.
I believe what 'Boilerman" is saying is that the inner ring/shell of the HB is bolted to the crank and will not wobble, unless the bolt backs off. The outer ring/shell of the HB will wobble when the seal between the inner and outer shell has failed. The failed seal causes the outer shell to rotate at a slight angle, thus causing belt misalignment.
It's like part of a bicycle tire bead not quite on the rim . The rim spins correctly, but the tire wobbles.
Mine wobbled....
Here's my take. I believe the above is correct. Assuming, (big assumption, I know) the center hub casting is true. The outer pulley ring on mine was far from true.
A gap measurable by a feeler gauge....
Other side's gap, you'd need a stack of feeler gauges to measure the gap...
Replacement belts only cured it until the belts had some miles on them, then sqeeeeeeek!
Like I said before the belt tension pulls on the rubber and if the car is not driven often the rubber gets a distorted memory and over time it does not recover. I think all GM balancers are made the same and cars driven every day don't have this problem. Corvettes sit more than any other car and have this problem more than others.
Here's my take. I believe the above is correct. Assuming, (big assumption, I know) the center hub casting is true. The outer pulley ring on mine was far from true.
A gap measurable by a feeler gauge....
Other side's gap, you'd need a stack of feeler gauges to measure the gap...
Replacement belts only cured it until the belts had some miles on them, then sqeeeeeeek!
Like I said before the belt tension pulls on the rubber and if the car is not driven often the rubber gets a distorted memory and over time it does not recover. I think all GM balancers are made the same and cars driven every day don't have this problem. Corvettes sit more than any other car and have this problem more than others.
If the distortion occurs while parked, then imagine while accessories are in play, water pump, AC clutch engages, power steering pump, oil sump pump (GS), alternator and along with higher rpm, all increase the HB load.
I still feel the rubber/silicone seal on the oem HB has a high fail rate whether parked or driven.
Last edited by Mike's LS3; 09-26-2016 at 03:58 PM.
If the distortion occurs while parked, then imagine while accessories are in play, water pump, AC clutch engages, power steering pump, oil sump pump (GS), alternator and along with higher rpm, all increase the HB load.
I still feel the rubber/silicone seal on the oem HB has a high fail rate whether parked or driven.
The OEM part is not as good as it could be but it is the same as used on other GM products and they don't have the fail rate. Why? Some even drive a fan and don't fail. You could find millions of V8 Chevy pickups with 200k plus miles with no balancer problems.
The OEM part is not as good as it could be but it is the same as used on other GM products and they don't have the fail rate. Why? Some even drive a fan and don't fail. You could find millions of V8 Chevy pickups with 200k plus miles with no balancer problems.
I'd be willing to bet if those Chevy pickups had 400+ HP LS2 or LS3 engines, the failure rate would be comparable to that of the C6 Vette.
Hey guys, if the car is staying mostly stock, as mine will, would you recommend the powerbond over the sumitt unit? they both sell for the same amount of 189
09-24-2016, 10:25 PM
Harmonic Balancer?
this explains the real reason for the balancer issue, but as also mentioned, check the other pulleys, especially the idler and tensioner.
