noises...how to fix??

[kylek325i]

Alright I have two noises I need to fix...I have read the old threads and stuff but if you have any obscure or out-of-the ordinary guesses please help!! I have a '94 325i, 153k on it-

Noise 1: Almost 99% sure something to do with the belts/ tensioner. Happens when car is cold(er) and lasts for only a second or two...a very high pitched squeal. happens infrequently and (seemingly)unrelated to anything. Happens both at idle and cruising at 60mph. Not as big a deal -yet- but I dont my BMW soundling like the I cant really tell where its coming from exactly...any ideas?

Noise 2: The elusive death rattle. I have not been able to locate it since it started maybe 5 months ago. I posted awhile ago about it. Sounds like its coming from drivetrain or exhaust...totally inconsistent and is worse on right turns. Will disappear, then pop up again and sound awful. I have replaced everything I can think of (trans mounts, guibo, rear suspension, muffler) except the driveshaft itself. One observation i made today was that the heavy insulation padding in the drive tunnel by the transmission output has started to fall down and hit the driveshaft from one side. This doesnt seem like it could possibly cause such a violent noise but I am out of ideas. Anyone know of a good way to secure this foam padding stuff to the tunnel wall? the good side is held on by a wimpy looking screw and big washer and looks ready to give way any time. ALSO i have heard of people using microphones to diagnose where sounds originate underneath their cars...Any idea what kind of microphone setup and where to get it??

thanks-
Kyle

[Teh Prof]

What the heck is a guibo, anyway, and why do we have them?

[nukeduster]

its a flexible rubber disc that mounts inline with the driveshaft and helps prevent unwanted drivetrain rattles and shocks.. acts as a softener between the transmission and rear end.