bbarcher, I had the timing chain tensioner replaced on our 1991 300CE at 77k miles due to a muffled clatter at the front of the engine. A local independent felt it was OK-as-is, but after some prompting the MB dealer's Service Department discovered that the tensioner wasn't holding oil pressure properly causing excess slack in the chain. A new timing chain tensioner eliminated the noise. As for the oil draining from the oil filter canister, that's normal ... when the oil filter is removed a check valve opens to drain the canister.

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Fred Hoelzle