I want to have the timing chain wear/stretch checked on my '81 300D (123 130 model with 617 engine). Our local dealer and another MB shop say it can't be done (probably just don't want to fool with it) but MB tech rep told me on the phone the instructions (28 steps) are in the service manual. (I know from past Shop Forum messages that this job can be done and should be done when have valve cover off to adjust valves.) I have a mechanic now who can and will do the job but he needs the instructions (they aren't in his Haynes book). Anyone have these who would email or fax me a copy? Thanks.

I did it not too long ago on my daughter's car. It's quite simple.

With a 27MM socket, the injector socket works great, turn the crankshaft clockwise to TDC slowly. With the valve cover removed, the marks on the camshaft and front bearing pedestal should line up. If the mark is not in sight, turn the crankshaft one more full turn clockwise slowly to TDC. If the mark is off much more than a degree or so, you can worry about it. If the oil has been changed frequently, which keeps the particulate matter out of the chain, you should not see any stretch.

It is not wise to turn the crankshaft at all counterclockwise, this will be turning against the rails. When I say clockwise or counterclockwise, I mean as you are standing in front of the car looking at the engine.

Good luck,

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Larry Bible
'84 Euro 240D, 523K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in
Mercedes automobiles

Thanks, I'll pass your message along to my mechanic.

duChemin, Please don't do what I did. I checked my chain and had about 6degrees of strech and ordered a new timing chain but I broke my foot and didn't get around to putting it on. When the chain broke, at 60MPH, it broke my cam into four pieces and broke two of the cam bearing towers. I'm going to pull the head this weekend and I"m not sure what I'll find.My 83-300D had 241k miles on her and the PO and I always gave her regular oil and filter changes.

Jay,

Regular oil changes, or frequent oil changes? There's a difference.

Good luck with what you find after removing the head. Keep us posted.

Larry