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Engine knock?

My daughters 1993 Buick Century has developed a troubling sound. We aren’t sure exactly where it’s coming from. Maybe the Engine. Anyways to me it sounds like something is rolling around, like in a dryer. Something loose maybe. When the engine is started and revved the rolling is still heard. It’s coming from the side of the engine that has Power Steering Unit, Water Pump and Airconditioning unit. We thought it might be the Power Steering unit because of a leak, so replaced that. No help. Same with the Water Pump. I didn’t think that an Engine Knock sounded like a loose part. Does anyone have a clue for me please. We can’t afford to replace this thing.

Remove the belt and turn the harmonic balancer. The pulley often breaks loose from the fly weight.

Thanks we will look at that, although we did have the belt off to replace the water pump, didn’t look that far down.

You were correct. Thanks for pointing this out. ALthough the $350 job we are looking at isn’t pretty. Since we don’t have the tools to work on it.

Thanks for the reply. My ego is quite fragile and I enjoy my head swelling when I am correct. Of course, my family and friends will suffer. But they will get over it.


I think I have the same thing. Since it is a costly repair and I got my 1992 Century from a friend for free, I want to ask you this: what if I keep driving with this sound? I mean, what impact does this pulley-balancer separation have on the engine or other parts of the vehicle?

The harmonic balancer can be bought at most McParts stores for less than $100 and for the mechanically inclined with a few basic tools it can be replace in less than an hour. Continuing to operate with the rattling harmonic balancer will eventually result in the pulley seperating from the balance weight and the belt dropping off.

Personally, I have pulled dozens of those pulleys off, welded the pulley to the fly weight and put the car back on the road charging 1 hour flat rate and never have had a failure… But if operated too long the wear will preclude this repair.

Good luck.

Thanks much for the encouraging info! I hope I am mechanically inclined enough. The current symptoms are (this car has everything on one long serpentine belt):

  1. noise;
  2. with the engine not running, I can move the belt some distance up or down until something bangs on something (metal on metal; sounds close to the noise, only a single bang);
  3. with the engine running and the belt on the noise is the worst when idling; it seems to go away when I press on accelerator (no matter in park or drive shift) and to get worse if i turn the steering wheel;
  4. with the engine running and the belt off (only for a few seconds not to overheat) the noise is still there, similar but less loud, so it is definitely not any other pulley on the belt.
    I will try to change it myself. I have found some advisory about using a special tool, the puller, Part #J38197, at
    (it is there under CRANKSHAFT DAMPER CAUTION ON 1991-93 3.3L VIN N)
    which concerns me since they say ``Failure to use the correct tool while removing the
    damper may cause damage to the one piece balancer/damper assembly."
    So, if you could please help with the following questions:
  1. Given the above symptoms, is it the balancer?
  2. Can I still do it if I do not have that special ‘puller’?
  3. Can it be fixed by welding in any condition? In my case it only started last week, so about 200 miles ago. Is it a simple welding around the whole thing or does it require any kind of balancing and/or creating a weld in some precise location? I just have no idea what’s inside the thing and how it is supposed to be but I should be able to find someone who will wled it for me.
    Thanks much again!