my GF just bought a 98 regal GS, it has engine noise that im not able to pinpoint. it is an idle/low RPM rattle that i thought might be the coupler but that was already replaced before the sale. i then thought it could be the rotor pack but i pulled the */c belt and started it and then noise was still there, im not sure if the rotors still spin a little with the belt off the pulley but it seemed like it. it is definitely not a rod/piston/lifter/rocker tick because its not always there and it doesnt change with RPMs. im kind of stumped as to what this could be, anyone here ever heard this noise before?

http://www.youtube.com/watch?v=wO5-AG-LTdo

sounds like the supercharger coupler. easy fix look here http://intense-racing.com/Merchant2/...3800_Induction

i dont think you read the post fully, the coupler had been replaced less than a month ago with the green zzp coupler. lets just say its not the coupler, what else could make that noise?

ya sorry missed that. did you check all the pulleys on the motor? they will make almost the same sound if they are about gone.

idler and tensioner are brand new. people on rivperformance and mnclubgp are sayin it could be the balancer but i dont know why the sound would be coming from the top of the engine like that. would any of the pulleys make a sound like that if they were bad or is it just certain pulleys? can a water pump pulley be bad without the water pump itself being bad? because im pretty sure the water pump is almost new and wouldnt the water pump make a constant noise that changes with RPM?
thanks for all the help so far.

the idler pulleys will make that sound for sure. don't believe it could be the balancer pulley. check the tensioner on the accessory belt. it'* not on the supercharger belt system since you had started it without that belt on and the noise was still there. also check the alternator pulley with the belt off. i had an alternator that made that sound when it went the voltage was fine even though one of the bearings went in it.

the */c pulley still moved slowly even with the belt off and revving the engine, you dont think it could be a bad rotor pack?
the alternator is brand new, but ill check all the pulleys with the belts off.
please tell me that theres no way that this is an internal engine noise, i just want to at least know its nothing like that where ill have to tear it down.

oh yeah and one more thing, is it ok to start the engine with both belts off to see if the noise goes away?

ya, but not for very long and make sure you have a well charged battery.

the only other bearings in the blower are the snout and rotor bearings if those are bad then time to disassemble the entire charger to replace them