So it's been a long couple of days working on the E63...started about a week maybe 2 weeks ago when I noticed this little squeal / grind coming from the engine. Seems to be coming from one of the three idler pullies, didn't think much of it but I did schedule an appointment to take the car into the dealership...I so shouldn't have waited! As I'm leaving for work I really noticed the engine noise...as I'm exiting the car seizes up and the steering wheel won't move! I open the hood and the idler pulley has fallen apart and the serpentine belt is toast! Melted plastic and shredded belt rubber everywhere! Decided to replace all three pulleys just in case and also this little mishap killed the battery so had to replace that too...but good news the E63 is back up and running and catastrophe was avoided! Can't imagine what would have happened if the car seized up going 80 mph on the highway!


Lesson here is folks if you hear that squel / grinding noise from the pulleys take the car in ASAP and don't wait like I did! Hope this info helps out fellow forum Members

So what caused the problem to begin with? How old are those belts? Glad to hear you avoided what could have been a fatal situation.

Not too sure what caused this to happen, I have a 2007 and it barely hit the 50k mark and I don't abuse the car at all...on another note if I wasn't in such a rush for parts I would have never purchased parts at the STEALERSHIP! Prices were at least double from sites online! LOL

Something similar happened to the E320 we had...at around 190k miles it developed a noise that sounded like water pump bearings or an idler pulley. Turned out being both, and the water pump ended up seizing up, shredded the belt, and so we replaced both idler pulley and water pump, and obviously the belt. It happens, was just a pain since it had to get towed home.

Same happened to me!!

What is the torque spec for that bolt that goes through the pulley?

Same thing happened to me twice last summer! They just replaced the belt the first time, didn't notice one of the pulley's was worn, and had to tow it again the next day. Pain in the ***. Mine didn't even have a loud squeal, just loss of power and hard to steer. Luckily I was able to pull over and stop quickly.

Weistec sells pulleys for our cars, both mine have these installed, a no brainer why anyone would install an OEM plastic pulley on an engine that turns 7K rpm. You only have to lose power steering once in the E Class to realize the engineering design fault. Upgrade now!!!

Happened on my old biturbo CL. Had to be towed. What a piece of junk plastic pulley. No warning for me just failure and no power anything.