Shoot, I'm in a hotel right now, so I can't go look at my car, but I think I recall it's the tensioner bearing pulley.
If you look, it should be obvious if you look and see what pulley the belt winds around.
See ya at the GTG at Alon's house in Beverly Hills. You are going to awfully impressed with the house.
2001 E430, Bourdeaux Red, Oyster interior.
1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".