Loud pulley rattling... help!

[Agentlongwood]

When the RPM drops below about 1000 a nasty rattle comes out of the engine bay. I thought it was the waterpump at first so I replaced it and the rattle continues. If I take the supercharger belt off, the noise continues. When I take both belts off the noise goes away. I totally thought it was the water pump since stickin my face down in the engine bay thats where it sounds like its coming from. If its the crank pulley would it make any noise with both belts off? Im tempted to run it with just the S/C belt on it and see if the noise happens. Im pullin my hair out so any help would be appreciated lol

 

[SJAndrew]

Could it be the tensioner rattling?

 

[blueguy]

I know I've tried always spraying WD-40 or some lubricant down there...and if the sound even remotely changes for a second at least you can attempt to pinpoint it ya know?

 

[TheOtherNick]

Get a stethoscope and listen to each pulley with it.

 

[Agentlongwood]

Get a stethoscope and listen to each pulley with it.

Lol, I work in a hospital so I have a stethascope in my room. if you bump it into anything its loud as hell, so I think usin it on a running engine would render me deaf. What I did do was this: I pulled the S/C belt off and it still made the noise. I pulled both belts and it went away. I put the S/C belt on WITHOUT the accessory belt and it made the noise again. Im thinking that means it has to be the crank pulley. My next question would be how much of a pain in the balls is that to replace

 

[blueguy]

Sounds like the coupler in the blower if it is just at idle...replace it.

 

[Agentlongwood]

If it was the SC coupler wouldn't the noise stop when the SC belt is taken off?