2002 Mercedes SLK 230
(R170 Chassis)

At 67,000 miles it was time to replace the serpentine belts.  The belt tensioner is loosened with a Torx E10 socket:

This can be used from a 3/8 ratchet — if you have an assistant to help with the belt.  Better yet, buy yourself a Serpentine Tool:

There is a front and rear belt.  The owners manual contains a belt routing diagram.  If you don’t have one, draw a diagram becasue it’s not as obvious as it looks.

Here’s a picture of the rear belt tensioner:

Here’s a picture with the Torx socket attached.  I’m pressing down on the ratchet to loosen the belt:

If you look carefully, you’ll see I was also changing the oil.  The belt replacement took about the same time as it took for the oil to drain.

Updated: January 2017
Contact: GerdHoeren at Gmail dot com