I don't remeber what MB service book I saw the 50K mile replacement in, but I saw it when I was looking up information about my car. That is when I learned about the defective tensioner and had mine replaced (this was when I first got the car). Perhaps the 16V, being a more performance car (with much of its life spent in high rpm's) had a suggested replacement time. I too agree the chain will last well beyond 50K, even 100K miles. But I do a lot of hard driving with my car, a good part of its life is spent on the track. So in keeping with the general race car rule (replace major parts ie. bushings, belts, chains, etc) at least every two years, I will replace my timing chain in 50K miles. Or the next time I am in the engine.
Tom, I don't remember the physical differences between the front engine cover but there are some. I had mine replaced two years ago. The difference in the timing chain tensioner is one of them has a spring. I beleive it is the old tensioner that has the spring. There have been three different designs of oil spray nozzles for the timing chain. The last of which was designed in July of 87. Its part number (for injection engines) is 102 180 08 43
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