symptoms of bad harmonic balancer?

KEVINV

Registered User
greetings,
can anyone tell me what the tell tale signs of the harmonic balancer going bad ? my 95 sc auto w/77000 miles goes into a bad shake when shifting from park to reverse or drive w/brake on.once you give it gas it goes away for the most part but it still seems to run rough.any ideas? recently had iac & cam sensor replaced.
 
I would bet money that your engine mounts are shot and completely collapsed. Are you getting a Check Engine light?
 
Best way is to observe the run-out of the crank pulley with the engine running. Any sign of a wobble is a sure sign the balancer is going south. Also use a mirror to see that the main center crank bolt and the 4 smaller pulley bolts are still there, plus check that they are tight. A broken center bolt is a common occurance on these cars & sometimes just a tad out of balance will loosen the smaller pulley assembly bolts as well. However, with 77k you should be ok; I just changed mine on my '94 with around 125k (as preventive maintenance), because on my '93 it broke at 150k & did a lot of damage.
You may also be suffering from broken engine or trans mounts, especially if the vibration occurs when shifting from drive to reverse. Rev the motor from under the hood and look to see if the motor lifts on one side; also check the sump clearance between the pan and the sub frame - I'd say anything less than 1/4" would indicate collapsed mounts. Are you leaking any power steering fluid as well, because a collapsed mount will cause the sump to rub on the PS lines.
 
hello Kevin,
check engine light does not come on.i will get under car tonite & look into mounts.thanks.
 
My white 89 has that problem...I thought maybe the HB was bad, but after watching it closely and looking it over, it looked fine. THEN I looked at the engine mounts ... :eek: Both mounts are totally ripped in two (the usual :rolleyes: ) AND the motor mount brackets are bent out of shape too! My friend took the car to a mechanic to get these "worked on" when he owned the car...now I remember why I do everything myself... He said that the mechanic replaced one of them (I found that it was the hard one that was left un-done) and patched the oil pan (cracked from banging the sub frame) So anyhow, less than a year later, both are wasted, and the engine is sitting on the oil pan.

Anyhow...I also say: check the motor mounts :) If you replace them yourself, make sure to take a peek at the oil pan too. Most SC's I've seen have a worn spot on them from failed motor mounts, and my white SC has had a crack as well. The pan is fairly thick, but I'm sure that some pans have a hole worn through them.

A quick way to get an idea about the motor mounts is to see if the oil filter is extremely close to the subframe. In one of my cars, I couldn't even change the filter...
 
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hey Doc,
thanks for the info. i am checking the mounts tonite after work.i hope thats what it is.its driving me crazy.

regards,

kevin
 
The check engine light comment was directed towards the crank position sensor being wiped out if his dampener was wobbling.
 
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