mercman -
do you mean the tensioner pulley or the idler wheel? I had to replace the $10 tensioner wheel (which is also the idler wheel) on my 3.8 Buick @ 60k mi. which was a snap because it is right at the top - another 10 min job!
on the Merc, the idler wheel should be a snap but the tensioner is in a tight spot to get at!
kosmos -
I finally got the belt on - but took me 2 hours not 10 min!
What I did:
cut off old belt
routed belt onto all pulleys - except AC at top front of engine.
jacked up front
removed splash guard under pulleys behind passenger front tire
with 13mm box wrench, pushed tensioner pulley up enough while my bride slipped belt unto AC pulley
next time it will take me 10 minutes!
Thanks!