yangchi

Sorry all, first time MB owner, have had my fair share of BMWs and rely on "realoem.com" for accurate parts diagram at times.<br /><br />I am experiencing problem with my belt... Long story short, as preventive maintenance, I replaced the belt at 100k mi, along with two idler pulleys. Few months later, tensioning pulley either sealed or melted. Replaced the pulley (kept the tension pulley), and again few months later, lower idler was making noise so I swapped it again. couple months later , belt shredded while driving and upper pulley broke off along with it. Replaced, and three weeks later, belt shredded. All pulleys seems fine, no noises, smooth, no sharp edges.

I just ordered the tensioner to see maybe spring is tired... But really at a lost here... They seem to all be aligned... Now I am thinking maybe the after market pulleys were missing or had different washer thickness....

Anyone has proper instruction or parts diagram for me to see what I am missing? This can't be this difficult...

kaane

Stop posting new threads. Check the belt length and post vin number if you want a diagram.

cetialpha5

I used the Continental kit on rockauto.com. No issues. Also when replacing the pulleys, there was a washer on one of them. The new ones didn't come with one. Maybe you're missing one of the washers and it's now misaligned so it'll shred the belt after a while.

konigstiger

V-belt current part # 0019931896, see attachments for pulley #s.

yangchi

2007 E350 4matic wagon WDBUH87X77X216472
thanks in advance!

yangchi

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Thanks for the diagram. Somehow it doesn't look exact even though the vin matches.

Upper idler pulley I seem to have another washer on the inside, as well as a rubber one that I saw from other postings should be there. It lines up with the other pulleys well.

The lower idler pulley doesn't come with any washer, but if I install without washers, it actually doesn't line up, so having a washer would actually bring it into alignment. But I don't have one nor do I know it takes one. My worry is parts from Amazon doesn't align. I have also ordered the tensioner just to make sure it isn't my tentioning assembly (pulley was already replaced). I don't think mine has that shock absorber looking thing. Maybe I missed it.

Can anyone confirm of these idler pulleys are directional (inside vs outside) and that upper has a washer between the block and the pulley, and the lower does not (or should it)?

kajtek1

https://www.mbdirectparts.com/auto-p...d-pulleys-scat
EPC drawings are not repair manual, but should give you starting point.
Even with lower quality of idler pulleys in last years, your experience seems extreme.
Meaning you have to have something wrong in the system.
Did you check your harmonic balancer for deterioration?
Alternator freewheeling clutch?