Forgive me but I am not used to these German cars. On any 35 year old American or British car with 250k miles I would automatically replace the rubber crank damper. For my 1985 300 CD I am wondering if Mercedes quality is so great that people don't find it necessary, or if people just don't know that this component could seriously degrade. What is your opinion?

Does it look damaged? Separated?, undue vibration? I'm not sure if people just change them out as prevention, I assume most would do so when replacing the oil seal since the balancer would need to be removed anyhow. Although mine is an OM603, the balancer is still original and in good visual shape, and oil leakage from the front nain seal is not bad enough to warrant replacing it yet at 300k miles.

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Stable Mates:
1987 300TD 310K mi (Hans)
2008 Jeep Grand Cherokee OM642 165k mi (Benzrokee)

In my 30 years of OM617 experience I have never heard of a crank dampner failure. They are pretty stout.

I had a problem on a 1983 300SD several years ago. The engine was running but the crankshaft pulley was not turning. The car had about 200,000 miles on it at that time.

That is not a damper failure, per se. The vibration damper is "sandwiched" between the pulley and balancing disc and has no real involvement in whether the pulley turns or not.

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When cryptography is outlawed, bayl bhgynjf jvyy unir cevinpl.

Here is my thought, there are several reports of the crankshaft pulley bolt working itself loose on high milage cars. A bolt working loose in a rotating assembly "should" require torque reversal. About the only way I figure torque reversal could happen is if the crankshaft damper failed to do its job. 35 years is an awful long time for a rubber crank damper, so I think if the crank bolt is loose, the damper is probably shot. I could easily be wrong, lord knows my wife wonders if I am ever right....

Anyhow it's not common with these Benz diesels(or their gasser m103/4 counterparts from what I've read) like it is with say toyotas of the 90's.
I've had one seperate but not jump off on a Pontiac 455, had a hell of a time figuring why it was running hot

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97 e300d, 78 300Dt, 95 E300d, 94 E320 estate

I had my only 300 SD front vibration damper fail. The crank bolt slipped which I suspected was caused by the deterioration of the rubber. It had some oil leaks which were ignored and diesel dripped on it when a careless person changed the filter. I also suspect the engine had not been cleaned in a decade or more.

I bought one damper at a junk yard then replace it upon failure within two weeks. The new one was an MB brand.

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84 300SD
85 380SE
83 528e
95 318ic