I changed the T-stat today. Then I started the car up to bleed the system. as soon as i did, i heard this horrible high pitched rattling noise. i couldn't locate it. as soon as i raised the RPM it either went away or raised pitch(im deaf as a doornail). i though it might be the */C coupler or the */C oil or a combo of the two. any ideas?

Harmonic Balancer? I know those can rattle like crazy...never actually heard one that was failing though. Check to see if it is coming apart...

This is what a fubar'd harmonic balancer sounds like. Similar?

http://members.shaw.ca/bonneville01/MVI_0003.avi

I think so, ill check in the morning

well today i took off the pulleys and unbolted the sc snout, my coupler is bad it'* horribly loose, and i found one of my tensioner pulleys are starting to go bad. so i guess i'll be going to zzp for some parts. maybe ill just happen to order a 3.4 pulley too!