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Old 09-04-2010, 12:49 PM
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sixto sixto is offline
smoke gets in your eyes
 
Join Date: Jun 2000
Location: Eastern TN
Posts: 20,841
Pulling the head is straightforward in these cars. The only tool you might not have is the triple square or double hex bit for the head bolts. You can get the proper tool for about $25 or a set of cheapo bits you slip into a 1/2" socket for half that. The rest of the set is useful if you work on an M102/3(/4?) and the rear suspension.

I can't think of any while-you're-in-there's other than thorough cleaning. It's a good time to check the lifters and replace any that have collapsed. If you don't have lifter noise, don't bother. You might find the upper chain guide is worn but that can be replaced without pulling the head. If the tensioner guide is worn, that'll require pulling the crank damper and front cover and a whole other can of worms.

A possible can of worms is checking IP timing. If the o-ring between the IP and block hasn't been replaced in a while (or ever), it can break leading to an oil leak if you adjust IP timing after putting the engine back together. There's no reason to touch the IP when pulling the head so there's no pressing need to check IP timing if you're happy with performance. But you might find pointy cogs on the cam sprocket in which case you should get a new sprocket and roll in a new chain. Then you should check IP timing.

A friend of mine just had the head gasket done on his 93 2.5. Cost about $2500 because the shop felt it needed new valve guides. Valve guides aren't a common problem with these cars even at 300K miles. Stick with MB brand valve seals if you feel the need. And consider farming out that job because you need $pecial tool$ to remove the valve springs.

Sixto
87 300D
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