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.

i recommend changing all the hydraulic lifters at once.they have a service life and although only some are bad now the rest will surely follow.why do the job twice?you wont be disappointed with the results.

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michael cole 1980 300SD gone now but not forgotten,87tdt,90 300te 4matic 95 e320 wagon

agreed - I'd like to replace them all, but at the moment I have more time than money, so I'll do what I have to now, and again later if I have to.

But the question still is - is that chain tensioner bolt a special tool job, or a regualr socket?

as for the chain tensioner im only familiar with the 603 engine.it was a 17 or 19 wrench required to back the tensioner out.was no trouble for me but the 5 cylinder could be different.

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michael cole 1980 300SD gone now but not forgotten,87tdt,90 300te 4matic 95 e320 wagon

Michael, thanks for the info. The manual has the 602 and 603 chain tensioner removal as the same document - so I am pretty sure they're exactly the same. So loks like it's regular socket.

Did you replace the chain tensioner seal? Do I need to?

Also, how long did the job take you? Taking off the camsproket, camshaft, etc. You see, I need to plan the after job beers to arrive naturally around sunset....

Cheers.

i didnt replace the chain tensioner seal.so far no leaks.overall the job went fairly fast.say 2 hrs each way for the Rand R.be very careful whilst unbolting the cam and scratch mark the cam gear and chain so you can reset to the original timing.definately recommend staying cool calm and collected during the proceedure.so any tasty liquid libation will definately be helpful

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michael cole 1980 300SD gone now but not forgotten,87tdt,90 300te 4matic 95 e320 wagon

Good call. Thanks for the info. I am always much less apprehensive going into a job knowing it is not rocket science.

I ahve the workshop manual, so I know the exact sequence for the camshaft take off too. Groovy.