Guides are toast, yours does what my 560 does... just change the plugs monthly as they will foul fast. $3-5k is what it will cost if you pay a shop to do the work. I would guess materials alone, including machine shop fees will be $1500 of that easily.

One of our members here just did this on his 420, his bill was just under $5k out the door and had piles of rubber replaced that needed to be done. Luckily his threads did not rip from the block.

Only thing that has kept me from doing my now is that I may rip threads from my block and I am not interested in pulling the motor right now.

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I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]