Thanks for the reply. Here's a couple of things I should have added.
The belt looks find, no glazed areas, no visible cracks and it's completely pliable.
I'm a novice when it comes to some components in the engine bay, do you know where the air pump is located. This might be suspect since a week ago I heard a very slight squeak on startup which dissappeared after warmup.
02 C32 AMG
84 190E 2.3 5 Spd