Pulled into the driveway with the '01 L and got out to open the gate with the engine running. I noticed a ratteling noise coming from the front of the vehicle. Popped the hood and the noise is coming from the front of the engine.
Shut it down and removed the blower belt. Started up and the noise is gone. After things cooled down I spun the idlers and the blower pulley by hand but can't replicate the noise. There doesn't seem to be any lateral play on any of them either. This happened right away with no warning. Which do you think it is, idler or blower bearing(s)?

 

Have you had your supercharger off? I had the same sound after reinstalling mine. I pulled it off and reinstalled it again and the sound was gone. I don't know if I didn't tighten it down to spec the first time or what...

 

Nope, never been off in 87k miles.