I have a 1989 buick park ave 6 cylinder 3.8 motor that I believe to have a bad harmonic balancer.\
It is a front wheel drive.
I hear a real loud knocking noise when starting the car and when it is running it quiets down and seems to run great.
I took the fan belts off and started it to see if any of the driven parts are making the noise and I still heard the knocking while starting but not as loud.
While the car was running I took a look underneath and saw that the harmonic balancer was not shaking froom side to side but it seemed to look as though it was knocking back and forth while rotating.
I then shut the engine down to inspect the harmonic balancer to be tight from side to side preasure and shaking but I could rotate the pulley with my hand very easily about a 10'th of a turn and seemed to be knocking at each end of the rotations end.
It sounds to be the same knock I hear while it is running.
The knock I hear is almost like a bell ringing when you hit it with a metal object but slightly muted.
It was like it was on a clutch of some sort.
It has some kind of wired gadget behind it I believe to be a sensor or something.
My question is this; should I be able to turn it that far by hand or is something gone ary with it and needs to be replaced.
Is it a clutch for timing ajustment for the computer to read and could this extra slap in the balancer be throwing the timing off.
It knocks real loud when starting the engine while cold but after running it a while the next restart its not as loud because the engine is warm.
Will this cause further damage to the motor if I drive it this way for a couple of weeks.
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