C6 Harmonic Balancer
Thread Starter
2nd Gear
Joined: Feb 2026
Posts: 2
Likes: 0
C6 Harmonic Balancer
Question I have a 05 and bought it with the harmonic balancer wobbling, replaced the HB and no wobble. Drove it for a couple weeks and the HB bolt backed out, and belt came off and the HB was torn up. Put a new HB on and now it wobbles again, any ideas on what to do. Both Harmonic balancers were Dorman, not sure if I need to get an OEM one or what.
Racer
Joined: May 2016
Posts: 361
Likes: 153
From: Clinton, Illinois
Hi there,
When you installed the first one, did you torque the bolt properly? Meaning, that bolt is a torque to yield. You must first torque the bolt to the correct foot pound spec, and then continue to tighten the bolt to the spec of degrees of additional turn. There is a certain degree of ":stretch" that must be achieved to insure proper installation. I installed a Dayco fluid balancer from Rock Auto Parts and have had no problems ever. If you buy a stock balancer, it is still subject to the same failure and the design. To my knowledge GM has never corrected that issue. I'm not sure but I think you also need to use Locktite thread locker on that bolt as well. I know a failed repair sucks, but it's better to know why it failed. If you did not follow the correct torque specs, or reused the original bolt, that is your likely source of the failure. Good luck and don't give up!
Mike F.
When you installed the first one, did you torque the bolt properly? Meaning, that bolt is a torque to yield. You must first torque the bolt to the correct foot pound spec, and then continue to tighten the bolt to the spec of degrees of additional turn. There is a certain degree of ":stretch" that must be achieved to insure proper installation. I installed a Dayco fluid balancer from Rock Auto Parts and have had no problems ever. If you buy a stock balancer, it is still subject to the same failure and the design. To my knowledge GM has never corrected that issue. I'm not sure but I think you also need to use Locktite thread locker on that bolt as well. I know a failed repair sucks, but it's better to know why it failed. If you did not follow the correct torque specs, or reused the original bolt, that is your likely source of the failure. Good luck and don't give up!
Mike F.
Thread Starter
2nd Gear
Joined: Feb 2026
Posts: 2
Likes: 0
Hi there,
When you installed the first one, did you torque the bolt properly? Meaning, that bolt is a torque to yield. You must first torque the bolt to the correct foot pound spec, and then continue to tighten the bolt to the spec of degrees of additional turn. There is a certain degree of ":stretch" that must be achieved to insure proper installation. I installed a Dayco fluid balancer from Rock Auto Parts and have had no problems ever. If you buy a stock balancer, it is still subject to the same failure and the design. To my knowledge GM has never corrected that issue. I'm not sure but I think you also need to use Locktite thread locker on that bolt as well. I know a failed repair sucks, but it's better to know why it failed. If you did not follow the correct torque specs, or reused the original bolt, that is your likely source of the failure. Good luck and don't give up!
Mike F.
When you installed the first one, did you torque the bolt properly? Meaning, that bolt is a torque to yield. You must first torque the bolt to the correct foot pound spec, and then continue to tighten the bolt to the spec of degrees of additional turn. There is a certain degree of ":stretch" that must be achieved to insure proper installation. I installed a Dayco fluid balancer from Rock Auto Parts and have had no problems ever. If you buy a stock balancer, it is still subject to the same failure and the design. To my knowledge GM has never corrected that issue. I'm not sure but I think you also need to use Locktite thread locker on that bolt as well. I know a failed repair sucks, but it's better to know why it failed. If you did not follow the correct torque specs, or reused the original bolt, that is your likely source of the failure. Good luck and don't give up!
Mike F.
Safety Car
Joined: Feb 2016
Posts: 4,457
Likes: 1,391
From: SC
I would never use a Dorman HB, they are worse than stock. You CAN NOT reuse the bolt. It's a "torque to yield" bolt that has to be replaced each time. You can't properly tighten it with an impact wrench. The wobble you have now is probably because the crank snout is buggered.
Safety Car
Joined: Aug 2017
Posts: 4,929
Likes: 2,340
From: Etobicoke (Toronto) Ontario
Nowhere in the GM installation instructions does it mention an impact gun. There’s a very specific 2 pass procedure to install the balancer. The new torque to yield bolt gets used only on the second pass. There are variations on what you need to remove or drop in order to have enough room to do the job, but the guts of the procedure are in the middle of the attached document.
Burning Brakes
Joined: Oct 2018
Posts: 930
Likes: 455
From: New Brunswick, Canada
You could argue that he didn't use the Milwaukee Hi-Torque Impact gun you reference. I can argue (like others) that the official replacement procedure does NOT say that using an impact gun (ANY impact gun) is an acceptable alternative. I can also argue that by not following the proper procedures, the OP has very likely created additional problems for themselves.
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Verdad Gallardo
Pro
Joined: Oct 2024
Posts: 728
Likes: 399
From: WI
With what the OP is saying, seems like it just did!
You could argue that he didn't use the Milwaukee Hi-Torque Impact gun you reference. I can argue (like others) that the official replacement procedure does NOT say that using an impact gun (ANY impact gun) is an acceptable alternative. I can also argue that by not following the proper procedures, the OP has very likely created additional problems for themselves.
You could argue that he didn't use the Milwaukee Hi-Torque Impact gun you reference. I can argue (like others) that the official replacement procedure does NOT say that using an impact gun (ANY impact gun) is an acceptable alternative. I can also argue that by not following the proper procedures, the OP has very likely created additional problems for themselves.
Safety Car
Joined: Aug 2017
Posts: 4,929
Likes: 2,340
From: Etobicoke (Toronto) Ontario
With what the OP is saying, seems like it just did!
You could argue that he didn't use the Milwaukee Hi-Torque Impact gun you reference. I can argue (like others) that the official replacement procedure does NOT say that using an impact gun (ANY impact gun) is an acceptable alternative. I can also argue that by not following the proper procedures, the OP has very likely created additional problems for themselves.
You could argue that he didn't use the Milwaukee Hi-Torque Impact gun you reference. I can argue (like others) that the official replacement procedure does NOT say that using an impact gun (ANY impact gun) is an acceptable alternative. I can also argue that by not following the proper procedures, the OP has very likely created additional problems for themselves.