C6 Harmonic balancer?
Thread Starter
8th Gear
Joined: Mar 2022
Posts: 8
Likes: 0
C6 Harmonic balancer?
Well I can tell this has been touched on 1000 times and bear with me because I haven’t even had my c6 for a week yet. I’m hearing a lot of horror stories about how bad the harmonic balancer are on our cars. Do almost all c6s need them replaced? Does anyone have higher end mileage and has NOT replaced their balance? I’m at 87k on my c6 and I’m not having any issues and the balancer seems to be flush and not wobbling with car running. I can’t seem to tell if it was replaced but man am I scared haha. I do not want to spend that money to fix it and I definitely don’t want to do it myself! Can anyone ease my mind?
Drifting
Joined: Aug 2021
Posts: 1,728
Likes: 861
If it's not making noise and not wobbling then don't worry about it.. there's lots of people here running the OEM balancer and have never had issues. It's not like it's just going to one data catastrophicly fail on you. It gives plenty of warning signs like wobbling and sporadic squeaking. When that starts to happen then you'll want to consider replacing it.
Le Mans Master
Joined: Feb 2014
Posts: 5,463
Likes: 1,138
From: Chino CA
There are plenty of cars here that have well over 100,000 miles on the original balancer. Like noted above, you will get plenty of warning when it starts to go. Don't worry about it and have fun with your new car. If you start hearing chirping or see your tensioner pulley shaking wildly, take a look down at your balancer and see if it is wobbling. Until then, drive it!!
Retired & lovin' it!
Joined: Mar 2005
Posts: 4,475
Likes: 549
From: Jackson NJ
Well I can tell this has been touched on 1000 times and bear with me because I haven’t even had my c6 for a week yet. I’m hearing a lot of horror stories about how bad the harmonic balancer are on our cars. Do almost all c6s need them replaced? Does anyone have higher end mileage and has NOT replaced their balance? I’m at 87k on my c6 and I’m not having any issues and the balancer seems to be flush and not wobbling with car running. I can’t seem to tell if it was replaced but man am I scared haha. I do not want to spend that money to fix it and I definitely don’t want to do it myself! Can anyone ease my mind?
Pro
Joined: Feb 2021
Posts: 729
Likes: 317
From: Ashevile, NC
This topic has been bantered around many times.....some guys say a little wobble is o-k, others say any wobble and it's toast!! I have an '05 with 36K on it and just replaced it. Others have said they've never had a problem. It's a pricy job if you can't do it yourself but it's not a terrible project if you're handy. Take a close look at the balancer at idle with a flashlight and see if you notice any wobble. If none or very little you're probably good. If it's fairly noticeable you're probably headed for a replacement. Also possible it's been done. If so there's probably an ATI or PowerBond label on the front of it. Bottom line is that it is a high failure item on all C-6's. Was a factory defective part from the get go. The balancer is two pieces, an outer and an inner with an elastomer band between the two. The elastomer begins to fail and work it's way out which causes the wobble. Very few guys have had a catastrophic failure where it literally flies apart. You'll usually get plenty of notice by way of a squeaky drive belt. The belt has to ride absolutely square in the balancer not to squeak, therefore the wobble causes the squeak as the belt is actually being "pinched" in it's grooves. Hope this helps. Don't let it keep you up at night, just something to be aware of!!
Cruising
Joined: Jul 2021
Posts: 14
Likes: 0
From: Johnston County, NC
Harmonic Balancer
Thank all of you for your insight and thoughts. I’ll probably wait now and keep an eye on it. The only mechanical item I replaced was the alternator because the factory one was anemic. I really do love this car and have no plans on replacing it. I receive compliments everywhere I take it. So far I replaced all fluids, front two tires, bake pads and rotors and left rear hub. I keep a battery maintainer on the battery when not running. This is my fun vehicle and not my daily driver. John
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Advanced
Joined: Sep 2021
Posts: 56
Likes: 6
From: New Jersey
It amazes me how terrible the HB's are, and yet some do not fail; I have a 2011 with 21k miles and I just had HPA do a cam swap for me; part of my motivation was a slightly wobbling, belt-squeaking balancer. When he took it apart, part of my oil pan was worn away from a previous balancer that failed and started walking back toward the engine. I bought the car with 19k last August, so that means in 19k miles, it had one OEM balancer totally separate and fail, and the replacement OEM balancer they put on was already beginning it's march to failure. I was surprised someone did the job and put back an OEM balancer; I replaced with a PowerBond.
Pro
Joined: Mar 2022
Posts: 547
Likes: 153
2013 25k miles had a very healthy wobble. It was a decent job to do myself. I shopped around about 5-6 vettes before buying mine and they all had a wobble, one was terrifying.
You must be a lucky one with nothing yet. But there is a couple ways they can fail, the wobble, rubber detach and your belt stops spinning and rubber detach and the outer ring will walk forward (and rub on your rack0 or walk back (and rub on your engine). Like others have said its not a problem until it is, just keep a watchful eye on it. If it was me they are so frequently problematic i would swap it out, provided you can afford it. The second i saw a little wobble i would jump on it immediately. No reason to strain or wear out bearings premature risking long term damage..
You must be a lucky one with nothing yet. But there is a couple ways they can fail, the wobble, rubber detach and your belt stops spinning and rubber detach and the outer ring will walk forward (and rub on your rack0 or walk back (and rub on your engine). Like others have said its not a problem until it is, just keep a watchful eye on it. If it was me they are so frequently problematic i would swap it out, provided you can afford it. The second i saw a little wobble i would jump on it immediately. No reason to strain or wear out bearings premature risking long term damage..
Pro
Joined: Dec 2007
Posts: 595
Likes: 241
From: Maine
2022 C6 of the Year Finalist - Unmodified
I bought my 2007 last fall. No harmonic balancer wobble/noise/etc (I checked it pretty regularly). This spring I passed someone on a 2 lane road and it immediately started squealing when I went WOT. I got off the road immediately and the balancer was already walking forward slightly, enough that the belt was one rib off. This was at ~51k miles.
Now it has an ATI Superdamper and Texas Speed cam so its not all bad.
Now it has an ATI Superdamper and Texas Speed cam so its not all bad.
Le Mans Master
Joined: Jun 2022
Posts: 6,821
Likes: 278
From: SE Ohio
Looking for information as I’m an under a year Corvette owner.
Before I bought my 09 base I looked at an 07 with a little under 30k miles. It chirped at start up and the HB wobble was noticeable and what seemed to me, significant. I researched and from what I read, the LS3 engines didn’t have the same level of HB issues as the LS2.
Any insights into the relative reliability of HBs on LS2 and LS3 engines is appreciated.
Before I bought my 09 base I looked at an 07 with a little under 30k miles. It chirped at start up and the HB wobble was noticeable and what seemed to me, significant. I researched and from what I read, the LS3 engines didn’t have the same level of HB issues as the LS2.
Any insights into the relative reliability of HBs on LS2 and LS3 engines is appreciated.
5th Gear
Joined: Jul 2025
Posts: 5
Likes: 0
2013 25k miles had a very healthy wobble. It was a decent job to do myself. I shopped around about 5-6 vettes before buying mine and they all had a wobble, one was terrifying.
You must be a lucky one with nothing yet. But there is a couple ways they can fail, the wobble, rubber detach and your belt stops spinning and rubber detach and the outer ring will walk forward (and rub on your rack0 or walk back (and rub on your engine). Like others have said its not a problem until it is, just keep a watchful eye on it. If it was me they are so frequently problematic i would swap it out, provided you can afford it. The second i saw a little wobble i would jump on it immediately. No reason to strain or wear out bearings premature risking long term damage..
You must be a lucky one with nothing yet. But there is a couple ways they can fail, the wobble, rubber detach and your belt stops spinning and rubber detach and the outer ring will walk forward (and rub on your rack0 or walk back (and rub on your engine). Like others have said its not a problem until it is, just keep a watchful eye on it. If it was me they are so frequently problematic i would swap it out, provided you can afford it. The second i saw a little wobble i would jump on it immediately. No reason to strain or wear out bearings premature risking long term damage..
Burning Brakes
Joined: Jan 2011
Posts: 819
Likes: 130
From: San Antonio TX
Well I can tell this has been touched on 1000 times and bear with me because I haven’t even had my c6 for a week yet. I’m hearing a lot of horror stories about how bad the harmonic balancer are on our cars. Do almost all c6s need them replaced? Does anyone have higher end mileage and has NOT replaced their balance? I’m at 87k on my c6 and I’m not having any issues and the balancer seems to be flush and not wobbling with car running. I can’t seem to tell if it was replaced but man am I scared haha. I do not want to spend that money to fix it and I definitely don’t want to do it myself! Can anyone ease my mind?
But as others have said, I wouldn't worry about just because.
Le Mans Master
Joined: Jun 2022
Posts: 6,821
Likes: 278
From: SE Ohio
What kind of price are we talking here? I just got an 06 C6 and it had a little chirping that the prior owner said wasn't an issue (I didn't know better). Now I learn about this harmonic balance issue and sure enough it's got the wobble. I'm not confident enough to do the replacement myself. Anyone have an idea on the cost for a shop to do it?
I would think it may be less expensive at a private shop. Labor seems to be the big issue. My BIL had an HB go bad on his C5. He’s a pretty good mechanic and replaced it himself but didn’t seem eager to do another one.
Burning Brakes
Joined: May 2019
Posts: 909
Likes: 452
From: North Dakota
Found out mine was bad when it wore out my AC belt which flew up and took out the CAM position sensor which started leaking oil ever so slowly. Had it replaced at a local shop. Not cheap...something like $1700. No problems since. Get a quality ATI if you get it done.
Burning Brakes
Joined: Oct 2018
Posts: 930
Likes: 455
From: New Brunswick, Canada
Well I can tell this has been touched on 1000 times and bear with me because I haven’t even had my c6 for a week yet. I’m hearing a lot of horror stories about how bad the harmonic balancer are on our cars. Do almost all c6s need them replaced? Does anyone have higher end mileage and has NOT replaced their balance? I’m at 87k on my c6 and I’m not having any issues and the balancer seems to be flush and not wobbling with car running. I can’t seem to tell if it was replaced but man am I scared haha. I do not want to spend that money to fix it and I definitely don’t want to do it myself! Can anyone ease my mind?
I am awaiting delivery of a Summit Racing SUM-C2501 harmonic balancer and bolt as I type this. If yours does need replacing, from what I've read, stay away from the OEM part as it could fail the same way at any time (like the original). All threads on this subject suggest changing to an aftermarket balancer, an ATI if you are supercharged and/or do a lot of track racing, and the Summit if you're more a daily driver.
As others have said, if your harmonic balancer is not wobbling or making noise, you don't have too much to worry about.
Melting Slicks
Joined: Dec 2003
Posts: 2,340
Likes: 723
From: Chicago N/W Suburbs
I wonder if the harmonic balancer issues apply more to the manual transmission where the engine is torqued a lot more frequently than with an automatic. Hitting the throttle hard all the time is naturally going to stress the HB more.