i have a 98 grand prix gtp. i have a rattleing noise comeing from the pulleys. i thought it was the tensioner pulley, cause i held my finger on the bolt holding on the tensioner pulley and i could feel the rattle, so i changed the pulley and there is still a rattle. any suggestions on what it could be?

Is it on the supercharger pulley? if so its the coupler in the supercharger, it needs to be replaced.

no i can feel it comeing from the tensioner pulley, so i changed the pulley and the rattle is still there. could it be the tensioner itself?

Does it go away when you rev the motor?

yes it does, it only does it at idle.

Ok so it only rattles when idling. The sound is coming from the idler. You replaced the pulley and the sound is still coming from the idler. Hmm I wonder what it could be.

no its comeing from the tensioner pulley, i replaced the pulley and it still rattles

If it goes away when you rev the motor it's the coupler on the S/C. If the tensioner was bad the pulley would be rocking back and forth pretty good and the belt would be real loose.


Get a long screwdriver put one end on the S/C snout and the handle to your ear. You will here the rattle much clearer.

ok thanks hercman. i kept feeling it from the tensioner pulley, so thats why i changed it. i also have a pulley close to the firewall, looking like it wobbles. not sure which pulley it is, would have to look again. would the coupler cause that too?

No the coupler won't cause your pulleys to wobble. The pullies on these cars tend to sieze up and fail. If the idler pulley by the fire wall is wobbling it's time for replacement ASAP.

If you want to ensure it's not the coupler remove the belt for the S/C start the car up and see if the rattling noise is still there.

ok thanks alot, i will try that