2011 C6, AT, base coupe with 3700 miles

My dealer replaced the harmonic balancer and belts after hearing a chirping sound.

I know there were harmonic balancer problems on some C5 models. Anyone else have this problem on a C6?

Greg

 

06 C6 A6 F55 at 59k miles, balancer replaced, separating outter belt ring with inter pulley hub, rubber, etc. creeping out!

 

Wow... You might want try the "SEARCH" button. There's many, many threads on here about C6 balancer issues.




D

 

Brand new 2011 coupe (297 miles). Replaced harmonic balancer because of chirping. This was on the 4th try. The dealer refused to believe it was the harmonic balancer and "fixed" the car 3 times before getting it right. It went bad again and I let GM have the car back.

 

HUM.. yeah it was a known issue on many of the C5s and early production numbers on the 05 C6's. The cranks are slightly tapered and pressure fit - no keyed crank/pulley (HB). Rediculous unknown reason why they did it that way???

On my C5, the 'fix' was a new style bolt with a diamond grit on the back of the bolt, that once tightened to humongous torque, fixed the problem so the HB bolt would not back out and cause the HB to slide every so slightly forward causing belt squeak, and/or ripping up belts. It was my understanding that was the core issue.

And, getting that bolt off the crank to put a new one in involves either lowering the sub frame or removing the steering rack (A major PIA) - all for a $3 bolt!

 

Although, more prevelent with early VIN 2005's the crank-bolt pulley problem can happen with any model year C6. After building tens of millions of engines without this issue I never understood why GM abandoned the keyway. All of the Gen III and Gen IV V8 engines use a press-fit damper with no keyway and it's been this way since the LS1 was introduced in 1997. To the best of my knowledge the friction washer mentioned became a production part in the 2006 LS2 and LS7 (and I suspect this was the 'fix' for late model 2005's as well). IMO the only sure-fire fix is to pin the crank...with forced induction applications pinning the crank is a necessity. Pinning the crank most often is not done with naturally aspirated applications but IMO if you're putting-down a lot of NA power it's still a good idea.

 

Just had mine replaced on my SC'd 06. It was doing the wooble/chirp. Mine was pinned(Vette Drs) but it doesnt solve the problem.

 

I think the problem people are seeing now is the balancer itself coming apart/loose. Not the crank bolt coming out. (previous problem) I'm going to get mine done due to excess wobble.

 

Yeah I had the birdie chirps after a couple hundred miles on the 2010 GS. Dealer said there was a memo on it, and the solution was to replace the sepertine belt. No issues since.

Mark

 

Completely different situation. When you look down at the pulley with the engine running and see it wobbling so much you think it might fly off at any second, a simple belt swap aint fixing it.

 

Many people are affected with this issue.

I think it is designed to have the balancer blow up instead of the crank IMO.

I have had mine done twice in 38K miles from new.

Its an unfortunate problem, but with the huge HP and torque of the C6 I can understand why these blow up.

 

More of a design flaw than "huge hp/tq" issue. There are quite a few car models with quite a lot more hp that dont have balancers come apart.

 

Thats just it "other cars".

Let me clarify my point.

I was referring specifically to the C6 and GM as to the level of quality and design that we get from them at the C6 price point.

I can wish for but don't expect cutting edge technology or design from GM with this car. I can deal with a few low tech flaws with the great value we get with the C6.

I don't think we will see a quantum shift in the C7 either.

 

same thing happened to me. I went with a 1 piece HB

 

A chirping belt has ABSOLUTELY nothing to do with PINNING THE CRANK. The chirping of the belt is caused by wobble in the harmonic balancer that is caused by a failing flexible connection in the harmonic balancer.

 

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I beg to differ with you (at least in my case) My C5 went in 4 times to the dealer for "belt chirp". First time, just replace the belt - second, replaced the idle pulleys/tensioners - third time, replace the water pump (and new belt), and last but not least....this "new" diamond crusted bolt had JUST come out), replaced JUST the bolt. In additon to the squeak and chirp it was also jumping off one of the 5 pulley tracks eventually shredding the belt. They did NOT replace the Harmonic Balancer - problem solved for the next 8,000 miles no matter the weather and not another chirp out of it. Was still working perfectly when I sold it over a year later. .
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I respectfully offer you the video PRIOR to getting the new bolt.
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...BIRD CHIRPING VIDEO...
.
.

 

Nice video. But first that belt is not chirping. Second that pulley is barely wobbling and would never throw the belt.
If the bolt were loose, the pulley would have spun on the front of the crank probably damaging it beyond repair.
I don't know what they did or what the problem was but your story just doesn't add up, to me at least.

 

I looked at the vid of diy. I really don't think that pulley is wobbling at all, or if it is, it is so slight that it wouldn't cause any issues. I can't identify the noise, but it doesn't sound belt-related from what I can hear.

 

Not allways. I've seen an oem pulley slipping just enough (with limited wobble) causing a slight noise yet the crank wasn't damaged due to catching it fairly early. Problem was resolved by pinning and installing an aftermarket pulley.

Going through the hassle and/or cost of changing-out the pulley
and not pinning a crank pulley that is pressed-on is Some will argue this point but it's cheap insurance IMHO.

If you listen to the video, that is exactly what is going on. The pulley is slipping enough to cause the chirping yet it doesn't wobble much. Pretty simple to figure out once you've seen this happen once or twice.

 

What, is it not totally obvious that the pulley is NOT in the correct position? Both the main serpentine and the A/C belt are about a groove off, or - it HAS moved forward but is still clearly gripping the crankshaft and isn't moving backwards or forwards, (begins at 13 seconds through 18 seconds in the vid)

I took the best offset box wrench I could find (a socket would not fit) and put it on a cheater pipe and still coud not budge the bolt at all!
I'm thinkin I recall that bolt torque spec at over 185 ft lbs. It's a "torque to...then 1/8 more turn" - one time use bolt.

I never said it was throwing any belts. I said it was off the correct groves and over time the back part of the belt (towards the block) would start to shred over a couple of weeks time.

Call the noise what you want.. with the hood down and sitting inside the car, sorry - but I call it a 'chirping' sound ...

Point is there was nothing wrong with the HB - no wobble, no disintegration or delamination. If it was, the shop would have replaced it. As it's a real PIA, I'm sure they didn't want to see that car again after the newly desinged bolt worked - at least on my car. BTW the replacement bolt is black, not a galvanized look as the OEM one

I destest when someone makes the comment "your story doesn't add up" when you've got a video clearly showing the obvious.

Armchair diagnostics....