JCtx

Can somebody enlighten me what's the problem with the balancer? Or more importantly, how can it go bad? It's just the freaking pulley attached to the crankshaft, right? And finally, when was it supposedly 'improved'? Hope my '12 GS with 09/11 build date has it already. Thx.

ricknyc23

I think you are safe with a 2012....I think most that are affected are 2005-2007...

JCtx

Thanks man. But what was the problem in the first place? Does it crack or something? Don't understand how a solid metal part can go bad. Or were they defective since day 1? Just curious. Take care.

EVRose

It's not solid metal. It's made in two pieces with rubber between them. I'm not sure what goes wrong but the center piece usually stays true and the outer piece starts to wobble like the rubber between them is defective.

C6topless

The prior post is correct in the description of the Harmonic Balancer -- it is not a solid piece of metal.

This problem has been around for some time and GM thought the problem first was related to the bolt / washer used to secure the Harmonic Balancer. Turns out, they were wrong.

While I am not exactly sure what is causing the the Harmonic Balancer to degrade and fail, it is occuring in other makes/model of GM vehicles that utalized the old model. It is not limited to the Corvette family.

Finally, recently GM has switched to a new vendor -- though I am not sure when that change actually went into effect to say with any degree of certainty your Vette will not be affected.

cryoman07

Pick the vette up on Tuesday. The part came in exactly when predicted by another poster. After 24 days without my car, I think I will treat it to a nice run through the mountains and a nice bath afterwards.

bandit69

Well after a email to Chevrolet customer care and a phone call next thing you know the dealer service rep is calling to tell me the part is in and the car will be ready Monday at the latest. That is when I said that I had been in contact with customer care (he said he knew he had received a call also) and that I was expecting GM to cover the cost of this repair even though I am two months past my warranty period. I mean hey this is clearly a systemic problem and a major inconvience when no loaner is offered. He said he would see what he can do (OK, Yea Sure!!!). Anyway will keep you all posted on my progress....

Regards

SteveC68

What is the part number for the improved balancer?

torquetube

They weren't wrong. That was a separate, less common problem (a loose bolt) that is frequently conflated with failure of the balancer itself.

But it's true that most of these wobbing balancers aren't coming loose from the crank. Pinning and Loc-Tite wouldn't have made any difference. The pulley assembly itself is stretching apart.

JCtx

Now I understand; thanks a bunch man . The problem is obviously with the rubber then. It's so thin that it looks like one piece; learned something new today . Guess this issue is rare on new cars, but more common in older cars, when rubber starts to degrade with age and heat.

My new question is if other brands also use the same 'harmonic balancer'? Have never removed one on my cars, therefore haven't scrutinized one yet. Since the accessory belts are rubber, I don't see the need to 'rubberize' the crankshaft pulley, but maybe there's a valid reason. Thanks gang.

ricknyc23

found out friday my part is in as well! car should be ready monday or tuesday...finally!!!

neveret

can one of you guys get the new part #?

C6topless

My Vette was also completed on Monday with the new Harmonic Dapener -- part number on my invoice is 1-12635652 for the balancer ... and 1-12557840 for the bolt....

I know what I received was in fact from the new batch recently sent to GM from the new vendor... not sure if my dealership used the old part number on my invoice.

Quick observation -- absolutely no squeel at all and it is running extremely smooth ... no wobble at all -- far superior than when I first bought my Vette...

As for service --excellent. can't complain at all.

C6topless

one additional comment -- I was standing around talking to the service manager and he indicated that cause of this problem is related to the metal used as it was degrading faster than expected in some of the HB (like mine) . I wanted to discuss more with him as to his source of this information but two Vettes rolled in needing HB replacement as I was standing there.

ricknyc23

Got mine back yesterday as well....Looks like all is well again...

SteveC68

I called my local Chevy dealer and gave them the part number listed above (12635652), and he said they have 4 in stock and that it is a normally stocked item. I'm not so sure that is a new part number. The price he gave me was $258.

edit:

Found another thread with this same part number from June of last year. So if this is a new balancer it's not that new.

http://www.cadillacforums.com/forums...ancer-ls2.html

torquetube

For whatever it's worth: I replaced the harmonic balancer on my '06 C6 (LS2) in the Summer of '09. The replacement wobbles a little bit. The parts invoice lists the balancer part number as 12598831.

SteveC68

12598831 seems to be superceded by 12635652, so maybe it has been a year since the new ones have been out. The guy I talked to did say they were very hard to get.

C6topless

Dealers have the new stock now and the old part had been exhausted

JCtx

It'd be nice to know to see if the same problem is in our future or not. My '12 was built back in Sep 15, so it sat for a while at the dealer's warehouse.