93 mercedes auto belt tensioner
 

I wonder what the aduster is for, since there is a automatic belt tensioner on this 300se.Is there a actual procedure to follow before you remove the old belt.Vinag the belt I replaced is the same length.I tried playing with the aduster but nothing happen.Waiting for some answer.Thanks

Find the belt diagram in your manual and make sure that you are installing it correctly, as Jim suggested.
Does your tensioner have a torx end (star shape) sticking out of the middle of the pulley?

Vin