Harmonic balancer wobble
10-29-2009, 02:00 PM
#1
Safety Car
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St. Jude Donor '08
Harmonic balancer wobble
I installed a 160 stat a few days ago and while it was warming up after the install I noticed there was a slight wobble to the harmonic balancer. Just a little bit. I know the C6 had some issues with this. Are there similar issues with the C5? I called the dealer and they did not think the C5 had that same problem. thanks
10-29-2009, 03:27 PM
#2
Do a search and you will find several threads about this very problem over the past 2 weeks. Yes the balancer on the C5 is very subject to coming apart after a few years. There is also a problem where the bolt that holds the balancer in place backs out. The balancer on the stock C5 is not keyed in place. Rather GM chose to just use a pressed fit with the bolt holding it on. If the bolt loosens then the tension of the belts wants to walk the balancer off the end of the crank. Fortunately the steering rack is in the way of the bolt coming completely out but the balancer can wobble enough to spit off or tear up the belts. Look carefully and check the condition of the balancer and the bolt holding it on.
I have an aftermarket balancer that is pinned in place. If you find that your OEM balancer is coming apart, spend the few extra bucks and get an aftermarket balancer and have it pinned.
Here's an active thread on this subject:
http://forums.corvetteforum.com/c5-t...pping-off.html
I have an aftermarket balancer that is pinned in place. If you find that your OEM balancer is coming apart, spend the few extra bucks and get an aftermarket balancer and have it pinned.
Here's an active thread on this subject:
http://forums.corvetteforum.com/c5-t...pping-off.html
10-29-2009, 05:58 PM
#4
Pro
Good advice from 8VETTE7. I had to replace mine at about 70,000 miles, and it is a real pain access and remove/replace the balancer. The steering rack has to be removed (at least on mine) and the labor cost, if done at a Goodwrench facility, will set you back a few dollars, but replacement is certainly much better than having it back off and do some real damage and leaving you stranded.
Bronk
Bronk
10-29-2009, 09:49 PM
#5
Le Mans Master
Well known C5 problem - my first one lasted about 20,000 miles - replaced under warranty.
10-29-2009, 09:58 PM
#6
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Mine lasted 18k miles, but the warranty had expired. I replaced it with a Powerbond underdrive unit and haven't looked back.
I do wish I had done a cam at the same time, since I had almost all of the stuff off the front.
I do wish I had done a cam at the same time, since I had almost all of the stuff off the front.
10-29-2009, 10:09 PM
#7
Le Mans Master
29,500 miles also replaced under warranty.
10-30-2009, 08:11 PM
#10
Melting Slicks
Had it happen on mine - out of warranty. The bolt came loose and it was spinning belts off. Considered an underdrive but stopped by the dealer and spoke to a service tech I've known for awhile.
He says GM has come out with a different bolt that has (for lack of a better word) diamond grit on a new bolt they are using. They took a look and replaced mine for nothing. Had to wait a few days until they were re-supplied with this new bolt. Once torqued down the diamond grit digs into the balancer to keep the bolt from backing out.
They did not have to remove the steering rack but said instead they loosened up some sub frame bolts to get the original out and put the new one in. The torque value was ridiculous - like 300 ft pounds or something like that.
No trouble since 20k+ miles.
They said that is the exact same fix they were using on the early C6's to fix the problem.
He says GM has come out with a different bolt that has (for lack of a better word) diamond grit on a new bolt they are using. They took a look and replaced mine for nothing. Had to wait a few days until they were re-supplied with this new bolt. Once torqued down the diamond grit digs into the balancer to keep the bolt from backing out.
They did not have to remove the steering rack but said instead they loosened up some sub frame bolts to get the original out and put the new one in. The torque value was ridiculous - like 300 ft pounds or something like that.
No trouble since 20k+ miles.
They said that is the exact same fix they were using on the early C6's to fix the problem.
10-30-2009, 10:48 PM
#12
Burning Brakes
replace it while you still can drive the car . I got a fluiddampner it gave me a real smooth idle and at high rpm also. make sure you also replace the center bolt and that it's torqued correctly
Last edited by road dog; 11-09-2009 at 08:59 PM. Reason: added info
11-09-2009, 07:50 PM
#14
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Had it happen on mine - out of warranty. The bolt came loose and it was spinning belts off. Considered an underdrive but stopped by the dealer and spoke to a service tech I've known for awhile.
He says GM has come out with a different bolt that has (for lack of a better word) diamond grit on a new bolt they are using. They took a look and replaced mine for nothing. Had to wait a few days until they were re-supplied with this new bolt. Once torqued down the diamond grit digs into the balancer to keep the bolt from backing out.
They did not have to remove the steering rack but said instead they loosened up some sub frame bolts to get the original out and put the new one in. The torque value was ridiculous - like 300 ft pounds or something like that.
No trouble since 20k+ miles.
They said that is the exact same fix they were using on the early C6's to fix the problem.
He says GM has come out with a different bolt that has (for lack of a better word) diamond grit on a new bolt they are using. They took a look and replaced mine for nothing. Had to wait a few days until they were re-supplied with this new bolt. Once torqued down the diamond grit digs into the balancer to keep the bolt from backing out.
They did not have to remove the steering rack but said instead they loosened up some sub frame bolts to get the original out and put the new one in. The torque value was ridiculous - like 300 ft pounds or something like that.
No trouble since 20k+ miles.
They said that is the exact same fix they were using on the early C6's to fix the problem.
11-23-2009, 08:21 AM
#15
Had it happen on mine - out of warranty. The bolt came loose and it was spinning belts off. Considered an underdrive but stopped by the dealer and spoke to a service tech I've known for awhile.
He says GM has come out with a different bolt that has (for lack of a better word) diamond grit on a new bolt they are using. They took a look and replaced mine for nothing. Had to wait a few days until they were re-supplied with this new bolt. Once torqued down the diamond grit digs into the balancer to keep the bolt from backing out.
They did not have to remove the steering rack but said instead they loosened up some sub frame bolts to get the original out and put the new one in. The torque value was ridiculous - like 300 ft pounds or something like that.
No trouble since 20k+ miles.
They said that is the exact same fix they were using on the early C6's to fix the problem.
He says GM has come out with a different bolt that has (for lack of a better word) diamond grit on a new bolt they are using. They took a look and replaced mine for nothing. Had to wait a few days until they were re-supplied with this new bolt. Once torqued down the diamond grit digs into the balancer to keep the bolt from backing out.
They did not have to remove the steering rack but said instead they loosened up some sub frame bolts to get the original out and put the new one in. The torque value was ridiculous - like 300 ft pounds or something like that.
No trouble since 20k+ miles.
They said that is the exact same fix they were using on the early C6's to fix the problem.
Wait, they didn't remove the steering rack? there is like an inch of clearance between the crank pulley and the rack. I'm about to tackle this procedure myself but if there is a way to do it without removing the steering rack then I'd really like to know
11-26-2009, 11:06 AM
#17
Melting Slicks
The service tech told me they were able to loosen some sub-frame bolts while in the air on a lift to give just enough clearance to get the bolt out.
I've not looked under to confirm if this is possible, so can not verify. When I got it back, I did use a mirror and flashlight to look at the new bolt. Instead of being sort of a galvanized or Zinc bolt, the new one is black, so I know they were not BS'ing me.
The new bolt has diamond chips on the back side of the bolt head that 'dig' into the balancer to keep it from backing out.
Thats all I know. The shop receipt showed just 40 min of labor.
I've not looked under to confirm if this is possible, so can not verify. When I got it back, I did use a mirror and flashlight to look at the new bolt. Instead of being sort of a galvanized or Zinc bolt, the new one is black, so I know they were not BS'ing me.
The new bolt has diamond chips on the back side of the bolt head that 'dig' into the balancer to keep it from backing out.
Thats all I know. The shop receipt showed just 40 min of labor.
07-16-2012, 02:00 PM
#18
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Which Dealership did you take your corvette to?
The service tech told me they were able to loosen some sub-frame bolts while in the air on a lift to give just enough clearance to get the bolt out.
I've not looked under to confirm if this is possible, so can not verify. When I got it back, I did use a mirror and flashlight to look at the new bolt. Instead of being sort of a galvanized or Zinc bolt, the new one is black, so I know they were not BS'ing me.
The new bolt has diamond chips on the back side of the bolt head that 'dig' into the balancer to keep it from backing out.
Thats all I know. The shop receipt showed just 40 min of labor.
I've not looked under to confirm if this is possible, so can not verify. When I got it back, I did use a mirror and flashlight to look at the new bolt. Instead of being sort of a galvanized or Zinc bolt, the new one is black, so I know they were not BS'ing me.
The new bolt has diamond chips on the back side of the bolt head that 'dig' into the balancer to keep it from backing out.
Thats all I know. The shop receipt showed just 40 min of labor.
07-16-2012, 02:16 PM
#19
Burning Brakes
Another C5 owner shared his experience with the balancer wobbling off. Thanks for the useful info. First, I have to recover from the expense of replacing the A/C compressor and idler wheel.
07-16-2012, 02:16 PM
#20
Team Owner
I am in no way telling you not to replace it. This is merely an observation. Since I've read about this on the forum a couple of years ago, I've looked at several balancers on C5's and all of them wobble "just a little" as you say. Enough to be noticeable if you're looking at it, but not enough to cause a problem.