OT: Harmonic Balance Failure

JDNewbie · Sep 1, 2014

My dad had the harmonic balancer "split" and rotate about 60 degrees out of place on his car. He replaced it and the car is running just fine, but we are a both scratching our heads a little trying to figure out what would cause that to happen. The car has the GM 3.8L V-6 with about 135,000 miles. We are assuming at this point that it just wore out. We've never seen a harmonic balancer go "bad".

Thanks.

Bob · Sep 1, 2014

They have a tougher job to do than most folks realize.

That being said, failed dampers on the 3.8/3800 are COMMON.

WGM · Sep 1, 2014

Th harmonic balancer on my 2011 Impala was replaced under warranty at 75K.

neverfear · Sep 1, 2014

Just replaced one on a 1990 Buick with the 3800.
It was knocking something awful. Thought at first it
was time for the boneyard.

Anonymous-0 · Sep 1, 2014

Had one go bad on our 1680 C/IH combine with the
Cummins engine.

Mike in Mn. · Sep 1, 2014

I have replaced a dozen of them on 3.8's, very common.

John B. · Sep 1, 2014

Yes they have a tough job more than any one
realizes. I've replaced quite a few of them on a
number of over the road engines. One little back
fire or pre-ignition can cause quite stress on the
old dampener.

CenTex Farmall · Sep 1, 2014

Sister's car kept overheating. Dealer couldn't figure out why. "Computer says nothing's wrong with it".

I took a look and did some fundamental troubleshooting. With #1 at TDC I notice the timing mark about 20 degrees off. Balancer outer ring had walked but didn't appear bad. Drew "new" mark and re-set timing, no more overheating.

Gambles · Sep 1, 2014

In a nutshell, you have two steel shells with rubber between them. Sometimes, the rubber just wears out, especially with extended heat and oil attacking it.
The last one I replaced was on a GM diesel pickup. IIRC, it would continue to spin after the engine was shut off.

howdy1960 · Sep 1, 2014

Have seen them go out on 350 Chebbies too. Like others said rubber ring gets old

Karl in MD · Sep 2, 2014

A friend of mine witnessed a drag car lose its harmonic balancer. It left with enough force that it killed a woman in the stands. They're nothing to take chances with.

OT: Harmonic Balance Failure

JDNewbie

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Bob

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WGM

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neverfear

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Anonymous-0

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Mike in Mn.

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John B.

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CenTex Farmall

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Gambles

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howdy1960

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Karl in MD

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