PontiacBonnevilleClub.com

Hello!
I just recently bought a 1996 Bonneville SSEI, with 155K miles. Car is nice for the miles! No rust underneath. I have had many Bonnevilles over the years but first time for a supercharged one.
There is a distinct rattle sound in the area of the supercharger nose drive. In my research, I've seen it described as rocks or gravel rolling around. This is the sound. Only at idle and more noticeable when warmed up. If I put my hand on the nose, I can feel like a knock inside, but I realize that could be transferring from something else. Also, when I shut the engine off, I hear the tumbling rock sound as the engine stops.
Could this be the coupler? Would it make that sound as the engine is shut off? Or should I be looking for something else?
The engine, otherwise, runs very well!
I haven't pulled the belt yet to check it, but that will be my next step.
Any info. will be appreciated!
Thanks!

Mark

Pretty sure it's the coupler. Also be prepared to feel some grinding in the bearings of the nose.

J Wikoff wrote:Pretty sure it's the coupler. Also be prepared to feel some grinding in the bearings of the nose.

Thanks John! If this is the case, will this cause damage to the rest of the supercharger body? or will a nose drive re-build/replace work... or replace entire supercharger unit? Gonna pull belt in the next couple days and go from there.

If you can get a nose with good bearings, that would probably be cheapest as far as time+money goes. Assuming yours does need work. I wouldn't wait too long, but it isn't likely to catastrophically die soon.