Like many others, over the last week or so I've found myself digging through post after post concerning issues with the stock harmonic balancers. Mine has started to cause a pretty annoying noise while idling that appears to go away at higher RPM's. The more I dig, the more I realize that this is a wide spread epidemic, not just a torque oversight on the first 11,000 cars. It appears that a majority of the failures are related to the bonded rubber core between the two metal portions of the pulley, which is a completly different issue than what folks were seeing on the early '05's.


I've started this poll just to try to get a good gauge of just how many folks are having issues related to their balancers. I've got a very early '05, #643 to be exact. It was never serviced for the TSB, but the bolt is still tight. The pulley wobbles similar to some of the videos that have been posted, but not so bad that I would consider it a problem... at least not until now that it's causing belt noise. I'm a complete DIY kiind of guy, so I'll be replacing mine myself. Unfortunatly, there's very limited information on the best route to accomplish this, so it's going to be a bit of a challenge. One thing that surprises me the most is how most folks are going back with another stock balancer?.. I don't believe I'll be going that route since there's no guarantee that I won't be doing this again in a few years. I know, an aftermarket unit can fail just as easily, but they seem to have a much better track record than the OEM ones.


The other thing that I find odd is that the failures really don't appear to be mileage related, but more time related with the life of the part. There are folks all over the mileage spectrum that are seeing failures, some as low as 12,000 miles and some not having issues until over 100,000 miles. The only thing that really appears to be common is the age of the vehicle. This makes me wonder if this issue will eventually affect most owners as the bond of the adhesive deteriorates, whether the car is being driven daily or even if it sits most of it's life.



Any and all comments are welcome, and by all means, if you have any tricks or methods on how to replace the balancer... please share them.





D

 

Is this an issue with all LS motors or just the LS2/LS3's?

 

Good question... I believe the only reports I've seen of issues are on LS2's. Not sure if any LS1's had this problem or not, but it appears they can use the same balancer as the LS2's. It would be interesting to see if any LS3's or LS7's had issues.





D

 

Mine is at the dealer getting new balancer this week. From what I have learned it seems like the trick with reinstall is getting the weights back on the same as the old one.

Mine is covered under GMPP with no out of pocket.

 

Hmmm... that seems odd to me. I have a hard time believing that every OEM pulley manufactured is made identically so transferring the weights over results in the same balance condition. Is the crank mated with a balancer and then balanced as a unit prior to the engine being built?

I thought the weights were installed when they manufacture the balancer itself and balance it. That way you install a "balanced" balancer onto an already balanced crank?.. I could be wrong though. Surely someone that knows will enlighten us.


Glad to see you got yours covered under warranty... saves about a grand out of pocket!




D

 

I am a newb with the balancer on the LS2. I have been watching mine for a year or so to see if it was going AWOL. When I started hearing very odd growl squeaking when cold I cked it and it was bad last week.

The weight reinstall is what I have been told at the dealership. I know the Tech that is working on my car so I will try to milk him for more info and then post it here. From what I have gleaned it seems like the whole bottom end was balanced as one unit at the factory.

 

"I'm a complete DIY kiind of guy, so I'll be replacing mine myself. Unfortunatly, there's very limited information on the best route to accomplish this, so it's going to be a bit of a challenge".


The complete, step by step procedure to replace the balancer is in TSB 05-06-01-001D (or a later letter than "D"). Get the TSB from GM

 

The TSB install was posted on here the other day .

 

had to change mine on 04 LS6,

 

Like I said mine is getting changed out this week:

06 with 28K on it.

 

I've seen/studied the TSB. From the bits and pieces that I've seen posted by others, there's easier ways of accomplishing the replacement though. GM's version books 7 hours plus for the job, others have said they've done it in 4 or less. The best "guide" I've seen so far is a section of A&A Corvette's super charger install guide. They show how to access the balancer to pin it which is the same access needed to change it.




D

 

Be aware that all LSx balancers wobble. If the balancer isn't moving out toward the steering rack, don't worry about it.

I'll bet the noise you hear is a belt tensioner bearing going bad. Worst case is the alternator going bad.

Tom

 

Oh, I would absolutley looooove for this to be the case, I'm really not looking forward to replacing this thing. Unfortunately, I've already replaced the tensioner thinking it would resolve the issue... no joy. As far as the alternator, I've given it thought but it passes the screw driver to an ear test. I've checked the water pump too, sounds quiet other than the water moving through it.




D

 

This is a given , no question. Small Nominal wobble is normal.

My wobble was huge, the rubber inside the balancer that absorbs the moment from the crank blew up.

Good point, I think my tensioner might be howling also.

 

[QUOTE=BigDs_C6;1576685176]I've seen/studied the TSB. From the bits and pieces that I've seen posted by others, there's easier ways of accomplishing the replacement though. GM's version books 7 hours plus for the job, others have said they've done it in 4 or less. The best "guide" I've seen so far is a section of A&A Corvette's super charger install guide. They show how to access the balancer to pin it which is the same access needed to change it.[QUOTE]

Then I suggest you use your best judgement from all the available sources, including the TSB which I agree seems overly involved. Good Luck.

 

OK, let's eliminate the alternator. With the engine running, unplug the wiring harness going into the alternator. If the noise stops, BINGO.

Have you tried removing the serpentine belt to see if the noise goes away?

Tom

 

Thanks for the vote of encouragement... maybe I can put together a nice "how to" after I get this done. I'm still in the early stages, gotta figure out which balancer I'm going to with for starters.




D

 

Hmmm... I'll give it a shot, but this sounds like it could hurt. I'm assuming this is to see if a winding is bad or something along that line? If it was a bearing in there this really wouldn't help. Then again, I should have heard a bearing when I was listening to it.



I've read about trying this, but really wasn't a big fan of running the car without the water pump going. I guess it would be fine if it was just for a couple minutes.




D

 

OK... pulled off both belts and started it up. Noise is still there but didn't seem as loud. I'm assuming that's due to the balancer not having as much load on it. The odd thing is it really only seems apparent when in gear. If I'm in park or neutral it's not very loud at all.




D

 

I like to work on my vehicles my self too,but this one looks like alot of work.I just bought this car and it has this issue. I'm having a Corvette Specialist fix it soon. -Wade-