Gentlemen,

The timing chain guides on my on my 1992 500E is made from plastic. it broke last week. As a result, the head had to be pulled to clean out all the debris inside the motor. It is a big cost. The garage where I took it to had worked on this problem quite a lot. My question is why mercedes would use such design approach. It seems to be contradicting to their philosophy of building long lasting car. The other question is is there a replacing part for the plastic guides? I'll ask my mechanic on this also.

Thanks in advance for your inputs.

Thanh
1988 M5
1992 500E

Almost all Benz & BMW engines use these plastic timing chain rails. The fault is in the tensioner on MB V-8's, if they fail then chain damage is certain. Most of the time a rattle on start-up is noticed well before failure. ALSO turning the engine backwards will cause the rails to fail! Many times failure happens after a water pump replacement as many techs turn the engine backwards to access bolts! OF course if they knew better THAT wouldn't happen. Tensioners fail due to oil change frequency. Or should I say lack of IT.