124 Chain Tensioner and Tappets R & R

[pdrayton]

I'm planning to replace 5 of the bucket tappets/ hydraulic valves / cam followers, call 'em what ya will..... on the wife's 300D 2.5 turbo. I found 5 of the tappets have more than clearance (one went all the way down) and 4 others went partially down when pushed with a drift.

But then I put Mobil 1 in and when I tested them on sunday, none of them were loose. At full operating temperature. But the engine still has the clack of a bad tappet. Why? Could they still be working loose when the engine is actaully running?

I really don't want to replace them if they are no longer the issue. However, I don't see what else it could be.

Anyway, the other question is do you need a special wrench for the chain tensioner? If so what? If not, what fits on that funky 12 point thing? A regular 12 point 13 mm socket?

HOw much of a mission is it to get that thing off? Doesn't look too hard in the workshop book, but who knows?
Thanks chaps.