Bad Harmonic Balancer

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Steve Horrillo - 10 Jan 2006 02:45 GMT

I reported in earlier posts that my belts on my '98 C5 were squeaking. I
took it to a friend's shop and he found that the rubber in the harmonic
balancer is all worn and wobbling. He said the belts are old and dry too.
The job is going to cost $679 total, new belts and all. He said it's a 4
hour job to get the harmonic balancer changed. Does that sound about right?

What gets me is that I just had the car at the dealer and they replaced two
tensioners. They said it needed new belts to stop the squeaking. Why didn't
they spot the bad harmonic balancer? Can I get away with not replacing it?
What happens when one fails?

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Warmest regards,

Steve

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Crabs - 10 Jan 2006 03:55 GMT

Steve:

> I reported in earlier posts that my belts on my '98 C5 were squeaking. I
> took it to a friend's shop and he found that the rubber in the harmonic
> balancer is all worn and wobbling. He said the belts are old and dry too.
> The job is going to cost $679 total, new belts and all. He said it's a 4
> hour job to get the harmonic balancer changed. Does that sound about right?

Seems about right. It's a rats nest of pipes, hoses, belts, and god
knows what in front of the LS1, and there's little to no room to get at
anything. All the accessories probably have to come off of the front of
the motor to access the harmonic balancer, and maybe even the radiator
and cooling hoses, can't really tell from the pictures I've found.
Regardless, there's a lot to be moved around just to get a hand down to
the area of interest.

> What gets me is that I just had the car at the dealer and they replaced two
> tensioners. They said it needed new belts to stop the squeaking. Why didn't
> they spot the bad harmonic balancer? Can I get away with not replacing it?
> What happens when one fails?

It's kind of hard to see from the top, maybe easier from the bottom.
It's not something that usually fails. Before I'd let them work on it
I'd check to see if there's any TSB's out on it.
To be quite honest, I smell a rat. I've owned quite a few cars over the
years (and most were GM, but not all...) and I've NEVER had a harmonic
balancer go bad.
Now, I'm not saying that it doesn't happen. It seems to be a common
failure on newer Mercedes (went surfing the NG's via Google). Didn't see
anything on LS1 HB's, so I doubt it a big failure item.
Get a second or third opinion.
What happens if it fails completely? As it wobbles it'll chew up the
front of the motor including timing chain cover & seal, as well as maybe
the lower pulley and serpentine belt. It could conceivably cause timing
chain problems and maybe even early crankshaft failure.

Good luck!
TomC
'90 ZR1 #792

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Steve Horrillo - 10 Jan 2006 05:28 GMT

> > What gets me is that I just had the car at the dealer and they replaced
> > two
[quoted text clipped - 9 lines]
> years (and most were GM, but not all...) and I've NEVER had a harmonic
> balancer go bad.

He put it up on the lift and showed me. The rubber part in the center of the
pully is all cracked and about an inch around the circumference there is no
rubber at all that I can see. When the engine is running it is slightly
wobbling. And it's in a real tight spot. He showed me on a Taurus how easy
it is to get to it. But on the Vette it's inches from the front of what
looks like the frame.

BTW, do you know the URL for Corvette TSB's?

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Warmest regards,

Steve

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Crabs - 10 Jan 2006 14:57 GMT

Steve:

> BTW, do you know the URL for Corvette TSB's?

http://www.alldata.com/TSB/10/981006iS.html

Here's a start.
Good luck!

TomC
'90 ZR1 #792

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Spud - 10 Jan 2006 15:16 GMT

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Ed McAllister, CCRM
Prime Property Management

> Steve:
>> BTW, do you know the URL for Corvette TSB's?
[quoted text clipped - 6 lines]
> TomC
> '90 ZR1 #792

Jeez, looked up my '04 LS6. Must be 30 or 40 items.

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Dad - 10 Jan 2006 16:37 GMT

> Steve:
>> I reported in earlier posts that my belts on my '98 C5 were
>> squeaking. I
>> took it to a friend's shop and he found that the rubber in the
>> harmonic
>> balancer is all worn and wobbling.

I doubt this is the case, it may be loose but no way the rubber is
worn in the balancer. Just to let you know the LS1 has an oil filled
crankshaft and if the bolt comes loose it will allow a black residue
to form. Would have said something earlier but I block spamm.

>> He said the belts are old and dry too.

The belts are old and dry after the first year, it's called flex and
heat checking.

>> The job is going to cost $679 total, new belts and all. He said
>> it's a 4
>> hour job to get the harmonic balancer changed. Does that sound
>> about right?

There is a new bolt that is used to reseal the crankshaft and lock the
balancer back on the crank and as far as I know they don't cost
hundred of dollars. More like an $80 fix.

> Seems about right. It's a rats nest of pipes, hoses, belts, and god
> knows what in front of the LS1, and there's little to no room to get
[quoted text clipped - 10 lines]
>> they spot the bad harmonic balancer? Can I get away with not
>> replacing it?

Let me guess, because there isn't one?

>> What happens when one fails?

The outer ring slips and the engine feels like the block is rotating
around the crank.

> It's kind of hard to see from the top, maybe easier from the bottom.
> It's not something that usually fails. Before I'd let them work on
> it I'd check to see if there's any TSB's out on it.
> To be quite honest, I smell a rat. I've owned quite a few cars over
> the years (and most were GM, but not all...) and I've NEVER had a
> harmonic balancer go bad.

Same here.

> Now, I'm not saying that it doesn't happen. It seems to be a common
> failure on newer Mercedes (went surfing the NG's via Google). Didn't
[quoted text clipped - 4 lines]
> maybe the lower pulley and serpentine belt. It could conceivably
> cause timing chain problems and maybe even early crankshaft failure.

Don't think so but since I've never seen one fail on a car it's a
guess at best. My best guess is that you would certainly feel it long
before it did that much damage unless it happened on the track at wide
open throttle.

> Good luck!
> TomC
> '90 ZR1 #792

Just to help your belief/disbelief in what I said I worked in the tool
and machine design department for a tier 1 supplier for harmonic
balancers from 1965 to 1968. We tested them to 20,000 RPM unbalanced
before we got any failures. That was most always ring separation and
not rubber deterioration and the rubber got very hot running like that
when unbalanced.

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Dad
05 C6 Silver/Red 6spd Z51
72 Shark Black/Black/4spd

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Steve Horrillo - 11 Jan 2006 00:13 GMT

> > Steve:
> >> I reported in earlier posts that my belts on my '98 C5 were
[quoted text clipped - 7 lines]
> crankshaft and if the bolt comes loose it will allow a black residue
> to form. Would have said something earlier but I block spamm.

I posted a up couple of close up pictures at
http://stephenhorrillo.com/C5_harmonic_balancer.htm. Let me know what you
think. Notice the gap, the cracking rubber and the way it's pushed in on one
side and hanging out on the other. If you need pictures with a higher
resolution or a movie of it spinning let me know.

Should I replace it? If I just replace the belts should the squeaking stop?
When I spray belt dressing on the main belt the sqeaking stops for a little
while but there's still a sort of rattleling sound.

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Many thanks Dad and everyone,

Steve

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RicSeyler - 11 Jan 2006 16:19 GMT

To quote a regular poster....
As Dad had been suffering much itching and discomfort, moved his belly
out of the way, fished around and finally found "Lil Dad", looked down
and uttered....

"Ugggh...I don't like the look of that!"

LOLOL

>http://stephenhorrillo.com/C5_harmonic_balancer.htm.
>

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sbright - 14 Jan 2006 10:54 GMT

Dad-

I know what you're saying..but.. I had an annoying squeeky belt on my 2000
C5. Ultimately, it was quited down by replacing the crankshaft pulley.
Hard to believe.. but it was "wobbly". Car had about 50K miles on it at the
time.

Steve- The pulley is reaplaced from the underneath. The steering rack
needs to come out to get at it. Procharger (ATI) has a kit to pin the
pulley to the crank. You basically drill a hole in the pin of the crank
which goes into the pulley and put a pin in it. In addition to being bolted
on with the big bolt which by the way is not supposed to be reused. I'm
telling you this because if you ever decide to supercharge your car(highly
recommended), your mechanic would have to repeat what he is doing here.
Four hours sounds right for the job.

-Stan
'99 Blown C5 Vert
'00 Coupe

>> > Steve:
>> >> I reported in earlier posts that my belts on my '98 C5 were
[quoted text clipped - 20 lines]
> little
> while but there's still a sort of rattleling sound.

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Steve Horrillo - 14 Jan 2006 12:22 GMT

> I know what you're saying..but.. I had an annoying squeeky belt on my
> 2000
> C5. Ultimately, it was quited down by replacing the crankshaft pulley.
> Hard to believe.. but it was "wobbly". Car had about 50K miles on it at
> the
> time.

So is the harmonic balancer the same as the crankshaft pulley? I have a
photo of what they told me was the harmonic balancer at
http://stephenhorrillo.com/C5_harmonic_balancer.htm

> Steve- The pulley is reaplaced from the underneath. The steering rack
> needs to come out to get at it. Procharger (ATI) has a kit to pin the
[quoted text clipped - 7 lines]
> recommended), your mechanic would have to repeat what he is doing here.
> Four hours sounds right for the job.

I mentioned replacing the bolt to the Chevy dealer and he said they never
replace the bolt. He said it's a huge bolt and is very strong. It seems no
one I take it to knows what they're doing. Not even the dealer.

The mechanic at my friend's shop (Midas Muffler) said it is wobbling, but I
can't see or feel any vibration or wobbling. I only hear a squeaking and can
see that the serpentine belt is chipped on the inside ridges. The Midas
mechanic showed me the cracking rubber on the harmonic balancer as proof it
was bad. The Chevy dealer said that the rubber gets little cracks in it and
dries out within a year and is not symptomatic of a problem. It's the
wobbling that is what I should be looking for. I have closeup pictures at
http://stephenhorrillo.com/C5_harmonic_balancer.htm if looking at a still
picture tells you anything.

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Many thanks,

Steve

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Dad - 14 Jan 2006 15:15 GMT

Did you just tighten the bolt to see if it had allowed it to "wobble"?
If you note his pictures the bolt head is off center, my guess is that
it's loose, not discentagrating. I'm sure replacing a good balancer
and tighten the bolt will also correct the problem, but costs more
than to tighten the bolt on the old one. Of course I'm still guessing
but if I had gone to the trouble of taking the pictures I might have
tried to tighten the bolt also. The rubber looked OK, although it did
have a bigger than normal gap.

Signature

Dad
05 C6 Silver/Red 6spd Z51
72 Shark Black/Black/4spd

> Dad-
>
[quoted text clipped - 45 lines]
>> a little
>> while but there's still a sort of rattleling sound.

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Stephen Horrillo - 16 Jan 2006 03:40 GMT

> Did you just tighten the bolt to see if it had allowed it to "wobble"?
> If you note his pictures the bolt head is off center, my guess is that
[quoted text clipped - 4 lines]
> tried to tighten the bolt also. The rubber looked OK, although it did
> have a bigger than normal gap.

I took the picture by driving up the parking stop. It wasn't up high enough
to check the bolt. Just high enough to stich my arm under the car. Great
observation though. Thanks. I'll have it retorqued and centered if possible.
Seems odd that it's possible that the mounting hole in the flywheel would be
large enough to be that far off center?

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All the best,

Stephen

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L DaVinci - 11 Jan 2006 00:07 GMT

Balancer problems have happened to C5s from time to time. And the C6
as well. It needs to be replaced ASAP. And the upgraded parts should
be used. Some like to pin the new balancer since it's still pressed
together and can still separate.

If you need more help, try:
www.corvettemechanic.com or
www.c5forum.com

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