Mercedes E320 CDI Serpentine Belt Replacement
If the serpentine belt looks like the one in this picture, It’s time to replace it. This car came poorly maintained and this was one of the items that needed replacement. You can replace it without removing the fan if you employ a certain tactic, which I will outline below. First, you can attach your wrench to the tensioner pulley ( shown below ), using a T40 wrench. You may/will need to use the wrench configuration shown below in order to get enough movement on the tensioner to replace the belt. If the old belt is like the one in the picture, it wasn’t necessary to use the 2 wrench setup to take it off as it was so stretched and didn’t require much movement of the tensioner to remove, however, it did require the setup shown below when it came to installing the new belt.
The diagram below shows use of 2 wrenches (since you’ll be unable to get your arm in the small space between the belt and fan), which will allow you to produce the necessary amount of CCW movement on the tensioner to get the new belt on. Think of the top wrench as a skinny arm. Pushing the top wrench in the direction shown will allow you to get the new belt on. You’ll have to pre-route the belt as shown as much as possible and the wrench setup will be the final step in adjusting the tensioner and slide the belt on the final pulley. I was able to slide the belt over the power steering pulley once I rotated the tensioner enough to do so. You will have to go between the bottom of the car and top portion for belt routing around all the pulleys.
Belt Routing Diagram
Pushing down on the top wrench as shown will move the tensioner to the left, allowing the belt to slide onto the final pulley. In this case, I used the power steering pulley as the final one, but you can use a different one if it works best for you. I posted a picture of the dual wrench setup below for your perusal. I simply put a large enough socket on the top wrench so as to fit over the handle of the lower one.