I took my 2011 Grand Sport to the dealership today to get an oil change. My car has around 50k miles (yes I drive my car ) Anyway, the mechanic told me my harmonic balancer needed repair. This is what was written on my service receipt…FOUND HARMONIC BALANCER PULLEY HAS SEPARATED FROM BALANCER ASSEMBLY. PULLEY WOBBLING CLOSE TO CONTACTING STEERING RACK. REPLACED HARMONIC BALANCER ASSEMBLY.
Now i'm no expert on this by any means, but this made my butt pucker a little. If I'm correct, if this pulley came off it would have been catastrophic to my engine and/or car, right?
What would cause this to come loose?
Is this something that is common with a car with the mileage I have?
With the high speed driving I do and LOTS of highway trips, I feel a little paranoid now. Not really looking forward to a piston flying out of my hood, into my windshield, then whacking me in the face!

Oh and one more thing…I didn't notice ANYTHING different about my car in regards to timing being off or strange noises etc. Which makes me even more worried…it's like a silent killer :-0

 

Do some searching, VERY common problem

 

Yea, pretty common. It really is something you should keep an eye on, on a regular basis. Just watch the crank pulley with the engine idling. If you see some wobble, get it checked. Many switch to an ATI or other aftermarket balancer when the time comes. No need to be paranoid, separation and damage are rare.

 

Thanks. I did do some research and found posts for the C5's and a couple on the LS2 but didn't see that it was still an issue with the LS3; then again, I guess an LS is an LS...

 

Well, the newer years C6, after '08-'09, are not nearly as problematic, but it still happens. Be happy the mechanic caught it, drive your car and enjoy it, just keep an "occasional" eye on it. It probably won't happen again.

 

The harmonic balancer coming loose on the crank snout is not uncommon. The bond between the hub and pulley failing isn't common. This might be something to watch for in higher mileage LS3's and LS7's.

 

I had these two items installed and never had a problem since. http://store.katechengines.com/bille...sioner-p2.aspx & http://store.katechengines.com/dampers-c41.aspx

 

Yes, it is VERY common. I had to have mine replaced on my car a week after I bought it and the with only 14k miles. It is covered by powertrain warranty though, a 2011 should still be under that.

 

Catastrophic failure is a very rare occurance. The more common way of failure is that the balancer starts to wobble and you start to hear a chirp in the belt. This all happens in slow motion and most of the time, you have thousands of miles in order to take care of it. So don't be worrying about a piston flying out of the hood on a trip. If you just keep a casual eye on the pulley and check it before going on a trip, you will have plenty of time to return from that trip in good shape. Remember that any problem with a car is magnified on a forum...there are many thousands of Corvettes out there that have never had a problem with the HB.

 

My replacement LS7 had about 14K miles on it when I noticed the crank pulley wobbling slightly. I took it to the dealer and the mechanic who replaced the engine said it was OK but he put a mark on the pulley for me to check to see if the pulley slipped. Everytime I track prepped the car I would check the mark. About 3 months later I was at a track event and heard an unusual noise coming from under the hood. After limping into the garage we found the pulley moving back and forth between the front cover and the steering rack. Step on the gas and it would move forward, leave off the gas it would go to the rear and as the engine idled it sat between the two extremes. Since I couldn't see any damage on the steering rack I was worried the noise was coming from hitting the front cover but it turned out there was no damage to it either. GMPP covered everything. One of the best investments I ever made.

Bill

 

Mine started chirping at 50k miles too. I replaced it with a Powerbond and it has been perfect since.

 

Remember also that what you call "high speed driving" is not high speed for the engine. At 80 mph, the engine is still spinning at less than 2,000 rpm. This is leisurely.

 

Precisely!

Damper runout can induced by the loose fitting of the OEM tensioner, as well as other pulley having runouts, on any system controlled with an one serpentine belt.

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Interesting to note members often recommend treating the damper runout casually.

From the moment it started, long before a casual owner notice - runouts has an adverse effect on crank and components connected to it. Purpose of the damper's being is to control harmonics - think where the crank harmonics go and what it does when it is no longer controlled.

The moment runout is noticed, never mind how long it was in that condition. Engine should be shut down to prevent further damage. Think even after repair, damages already done to the bearings/seals connected to the crank and the engine is never to be the same! Having the damper changed out and the engine still runs afterward doesn't mean the engine is still healthy! Those who changed with another OEM only further damaging their engine's internals.

Having a background in dealing with precision and knowing the shortcoming of the OEM damper, was reason for me to proactively change out to an stock diameter ATI before the OEM unit failed. As well as afterward, addition of the Katech tensioner, eliminating the OEM tensioner's induced runout, to further enhance the Serpentine belt system.



Side note: Back in '95, I installed a Fluiddamper on my '94 Astro Van - that also came with an same design damper on its iron block V6!

 

ATI or IW make great replacement pulleys.

Failure would not cause a piston to come out. Worst case it would toss the belt or stop spinning the accessories.