PontiacBonnevilleClub.com

Hi,
My 1993 Bonnie SSE S/C (68,000 k) recently started making out loud rattling sound that sounds like it's coming from the general area of the main serpentine belt on a trip returning to metro-Detroit from Ontario. Would just like some suggestions as to what this may be to help me pin-point the problem as I have to return this week. I read somewhere that belt-tensioners go quickly in Bonnevilles of this MY. I've had some exhaust work recently done, but it doesn't sound from that area. Any "hints" would really help.
Thanks!!!!!

Could be the plastic S/C coupler. An easy part to replace.

Unfortunately, we can't give any hints. There is a lot of moving parts on that side. To pinpoint it down, you will need to pull one belt off, see if the nose goes away, pull the second belt, see if the noise goes away. If you pull a belt off, and the noise goes away, check all pulleys. They should spin freely, so if you feel something funky, replace it.

It could also be a bad harmonic balancer. That can be diagnosed by grabbing the drive belt (engine off please!) and try and move it back and forth. If it has play in it, that is likely your issue. They usually have a metallic clunking at idle when they fail.

I hate to say, you are simply going to have to put a mechanic hat on, get in there, and track it down.

First of all, if you pull the belt to see if it goes away, DO NOT run the motor long or you could over heat it.

Does the noise go away once you bump the throttle? If so, this could narrow it down a little.

Does the noise seem to be up top or down low on the passenger side? High = SC coupler, Low = HB

Take off the first belt and grab the SC pulley and turn it, does it feel like there is slop? SC coupler bad

If no slop, start the car and see if noise is gone.

If noise is still there, remove second belt and start the car and see if noise is gone. If so, possible bad HB.

Hi guys,
That's for all of you suggestions. I'm going out to check it now. To answer a few of the responses it seems up high and when the engine is revved the noise remains.
Thanks again.
Joel

When my balancer went bad, the noise my car made reminded me of the old air-colled VW bugs. It was embarrasing. hope you can narrow your issue dow, as mentioned, it could be a few differnt things. Good Luck!