Had to take my '99 C230K in today. Heard an underhood noise that was identified as a tensioner problem. Car has 65,000 miles on it. I asked the tech when I should replace the timing chain and he said 100K. So about $1000 dollars later it's getting replaced along with the fan clutch and all the gaskets that go with it. I'm happy that was all it was, but unhappy that stupid things like this continue to break. Never had these issues with any other car. My last Mercedes.