Harmonic Damper
Thread Starter
Melting Slicks
Joined: Jun 1999
Posts: 2,263
Likes: 48
From: NJ
Harmonic Damper
At a recent Vette show, a C5 owner asked if my '04 ZO6 still had original harmonic damper. When I replied "yes," he said there are 2 kinds of GM OEM dampers that were installed on C5's....the kind that broke, & the kind that are about to...& when they do, it'll either take out your oil pan if it goes back, or your steering rack if it goes forward. He said it happens because the glue used to manufacture it dries out & the inner hub separates. He advised me to replace it asap.
Haven't had any issues...so far. No vibrations. Marked inner & outer hubs with white grease pencil awhile ago. Marks still line up.
What do you guys think? Preventative replacement??
Haven't had any issues...so far. No vibrations. Marked inner & outer hubs with white grease pencil awhile ago. Marks still line up.
What do you guys think? Preventative replacement??
Acct Suspended APR 2026 by request
Joined: Dec 2010
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2020 Corvette of the Year Finalist (performance mods)
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you have 3 options the way I see it...
1- be proactive and do it now, it isn't a matter of "if" it happens but rather "when"
2- wait until you notice it wobbling and then replace it
3- take your chances and wait until it fails and also risk spending more money replacing other parts that it takes out with it such as the front cover
personally I would rather be proactive about it, there is a new balancer thread probably every week so it is a well known issue... but on the other hand when they do fail they usually give you some warning before it falls completely apart so if you keep a good enough eye on it then you will probably catch it before it gets too bad
1- be proactive and do it now, it isn't a matter of "if" it happens but rather "when"
2- wait until you notice it wobbling and then replace it
3- take your chances and wait until it fails and also risk spending more money replacing other parts that it takes out with it such as the front cover
personally I would rather be proactive about it, there is a new balancer thread probably every week so it is a well known issue... but on the other hand when they do fail they usually give you some warning before it falls completely apart so if you keep a good enough eye on it then you will probably catch it before it gets too bad
Pro
Joined: Apr 2017
Posts: 711
Likes: 76
From: Atlantic Pa
I just replaced mine . What you heard is correct . It is not a matter of if ...it's a matter of when . You will probably hear the belt start to squeal before it bombs on you but why take the chance and risk damage ? My car is immaculate show quality and has only 30k on the clock but even being babied and stored in a pristine environment, it still had a balancer failure . The adhesive separates from the rubber ring and it will fail . It will fail for sure .Don't buy another gm factory balancer ! call summit and order yourself a 75$ replacement powerbond pb1117n. A new 10$ factory bolt and a 30$ new gatorback/ dayco belt . I had mine done for 300$ In labor at a local garage .its peace of mind and you won't save a thing in the end by having to call a flatbed to get your stranded car off the highway ruining your fun night out with the wife
Last edited by Lexybird; May 31, 2017 at 09:10 PM.
Drifting
Joined: Feb 2003
Posts: 1,761
Likes: 235
From: North Carolina
I just replaced mine . What you heard is correct . It is not a matter of if ...it's a matter of when . You will probably hear the belt start to squeal before it bombs on you but why take the chance and risk damage ? My car is immaculate show quality and has only 30k on the clock but even being babied and stored in a pristine environment, it still had a balancer failure . The adhesive separates from the rubber ring and it will fail . It will fail for sure .Don't buy another gm factory balancer ! call summit and order yourself a 75$ replacement powerbond pb1117n. A new 10$ factory bolt and a 30$ new gatorback/ dayco belt . I had mine done for 300$ In labor at a local garage .its peace of mind and you won't save a thing in the end by having to call a flatbed to get your stranded car off the highway ruining your fun night out with the wife
Recently had the 3rd balancer installed on my 41K mile 98. The second (oem) under warranty. New one is Powerbond from Summit, and new Gatorback belts. There doesn't seem to be a pattern on failure, I had 2 oem's fail in 19 years on a low mileage C5. In my case I think that the adhesive just breaks down.
Le Mans Master
Joined: Jun 2009
Posts: 6,528
Likes: 752
From: South Dakota
I had one fail at 30k miles and another one still going fine at 70k.
On the one that failed, I heard the belt chirping at idle. When I looked, the balancer was wobbling. I put on a Powerbond and it has been good. On my other one, I just keep an eye on it. If or when it starts wobbling or any signs of failure I will replace it.
Mileage is not a good indicator and a lot of them go well over 100k without failure. However, it is a known problem that you can see a lot of reports about on the forum.
On the one that failed, I heard the belt chirping at idle. When I looked, the balancer was wobbling. I put on a Powerbond and it has been good. On my other one, I just keep an eye on it. If or when it starts wobbling or any signs of failure I will replace it.
Mileage is not a good indicator and a lot of them go well over 100k without failure. However, it is a known problem that you can see a lot of reports about on the forum.
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Melting Slicks
Joined: Feb 2001
Posts: 2,791
Likes: 355
From: Northville, MI
The stock HB will do one of two things, it will separate or it will walk--move forward towards the PS. If it walks that is when it might damage the PS, however the more common results is it will throw the serpentine belt and destroy your hood insulation. Those HB that separate often are cars that are heat cycled and the glue is constantly heat cycling, common on low mileage cars. Those that have the balancer move forward on the crank are often those cars that are tracked.