When I ran into this problem, I found the attached information regarding the tools necessary and then I purchased them directly from the dealer (unable to locate anywhere else @ the time). The assembly tool 651 589 01 43 00 is the necessary tool to stretch the belt for removal / installation of the idler pulley. 651 589 05 63 00 also was helpful, but on the 2016 model I haven't had any success with the counterholder tool that is supposed to help with rotation of the crank pulley because it doesn't seem to reach deep enough to grab onto the head of the crank pulley bolts.

 

So how did you initially get the crank rotated to get the belt on? Which p/n belt did you use? I've been struggling with this damn thing all day now.

 

I bought the whole set and still ended up making my own countersunk crank tool bent from the straight one in the toolset using an inductive bolt remover vice fire-wrench. You absolutely need the idler pulley install tool once the belt is (finally) on. It also took a couple of tries to get the right belt, which is necessary too...

 

If you soak any belt in hot water for fifteen minutes, it will make the belt a lot more pliable and thus easier to install.

 

Yeah, but on a 2016 sprinter 2.1L, there's a special kinda hell for the AUX AC belt engineer......

 

I think a lot of MB engineers are in that corner........