Replaced the belt at about 82k miles with MB one. Probably the cheapest critical MB part I have ever purchased, less than $ 18 I recall.
Tool used to un-tension the tensioner: Amazon.com: 4346 Serpentine Belt Replace Tool for Mercedes Benz M270 Engine Belt Tensioner Wrench Serpentine Belt Tool MM# 270589000700 : Automotive
The tool didn't fit between the fender and the tensioner so I had to file off some of the tip to get it to actually fit and be able to install from below.
Once the clearance issue was fixed I couldn't get it to line up properly and I am not sure if the old belt was just so stretched or if the star on the tool was not attached properly, but I had to notch out the undertray to get enough angle to insert it and have enough swing to release tension. Once the new belt was installed, I certainly had enough angle to get it out so I think that the old belt stretched quite a bit, which makes me think I should just replace this every time the spark plugs are due.
You can see the hole in the old belt in the pics.
Tool used to un-tension the tensioner: Amazon.com: 4346 Serpentine Belt Replace Tool for Mercedes Benz M270 Engine Belt Tensioner Wrench Serpentine Belt Tool MM# 270589000700 : Automotive
The tool didn't fit between the fender and the tensioner so I had to file off some of the tip to get it to actually fit and be able to install from below.
Once the clearance issue was fixed I couldn't get it to line up properly and I am not sure if the old belt was just so stretched or if the star on the tool was not attached properly, but I had to notch out the undertray to get enough angle to insert it and have enough swing to release tension. Once the new belt was installed, I certainly had enough angle to get it out so I think that the old belt stretched quite a bit, which makes me think I should just replace this every time the spark plugs are due.
You can see the hole in the old belt in the pics.
