Loud screaching coming from belt area so I removed the top cover, removed the electric fan and slipped the belt off the tensioner pulley. The car is a 2003 with only 23k miles. Belt will be replaced, but not sure of pulleys. Idler pulley spins good but has rumbling sound so I think it needs replacing. The tensioner pulley doesn't make noise when spun but can be wiggled a little so I'm not sure if it's good or not. One thing I noticed was that the tensioner pulley was not riding in the center of the belt. The belt hangs over the front by almost a 1/4 of an inch. This seems suspect to me, does anyone know if this correct? I guess the easiest thing to do is replace all 3 since I'm in there but wondering who has experience with this. By the way, I thought this would be a hard job, but in less than 5 min I had the belt off. Hats off to MB on making this easy.