Have a whine coming from my engine. I replaced my power steering pump since Mercedes Service said that's what was causing the whine. Now they are telling me its the belt tensioner. Can anyone tell me if they have replaced one and how hard a job it is.

Thanks!!

 

There is this thread but it's for diesel... not sure how much in common there is or isn't:
http://www.mercedesshop.com/shopforu...d.php?p=469105

Couple of posts about the v-belt tensioner pulley in this thread:
http://www.pointedthree.com/disc/for...43&posts=1