I will be pulling the head off my '90 300E's M103 engine this weekend for a valve job. Are there any tips, pitfalls, "be careful's", etc. to know about? For example I have seen these for the M104, do they apply to the M103 as well? (especially #5 and #7):

1) a good time to replace the chain/tensioner also
2) always replace head bolts
3) replace the egr pipe
4) Watch the dowel pins for the intake. They often fall out during removal
5) "..no matter what anyone says, be sure and use a head gasket from MB. They have added Stainless inserts into the gasket at the front areas that leak. AND that special gasket is make only by ELRING!!"
6) If your lower timing cover is leaking now is the time to reseal. Make sure you clean the timing cover and block very well and use the gray permatex not the cheap red sealant .
7) "I have been called to a couple of general repair shops to diagnose broken cams after the work is completed. It turns out that many people are not aware of the fact the chain tensioner has to be run all the way through and re introduced through the closing plug. The chain just sings with the tensioner is ratcheted all the way forward."

Thanks guys,
Andy

No need to replace head bolts if they are sized within spec.

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2012 E350
2006 Callaway SC560

everything i have read.... this is just one step beyond all of the diy jobs i am capable of.....

i think the toughest was the a/c system.. about to do a water pump... can't even imagine pulling a head.


good luck... take lots of pics

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1989 300ce 129k
( facelifted front,updated tail lights, lowered suspension,bilstein sports, lorinser front spoiler, MOMO steering wheel, remus exhaust,stainless steel brake lines). (Gone)

1997 s320 154k (what a ride). Sold with 179k miles. Replaced with Hyundai Equus

1994 e320 Cabriolet 108k



1972 280se 4.5 153k Owned for 12 yrs, sorry I sold it


[/SIGPIC]

I imagine doing the AC system was a bit harder than pulling the head.....

I did not hesitate to R&R the evaporator. But the evaporator is not nearly as heavy as the cylinder head. I would be a bit reluctant to R&R the head, but I would tackle it if I were confident I could lift it out.

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2012 E350
2006 Callaway SC560

The head is mechanically more complicated than the evaporator and ou need more tools. The head is heavy but, two people can remove it with no much problems. The new head bolts are different than the originals...be careful! If you have time, this is a good time to powder coat your head cover and paint/cover your factory headers. You should have somebody who does this locally...
Good luck!

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J.H.
'86 300E

Andy, buy the MB sealant for the timing chain cover ... it's expensive (around $18 as I recall), but seals very well ... the tube works like a caulking gun.

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Fred Hoelzle

Thanks everyone. Very much appreciated.

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Andy_M
'98 W140 S320 Black/Black
'06 W164 ML500 AMG White/Grey
'03 Porsche 986 Midnight Blue/Grey

At least it's not a V6, then you'd have two of em to worry about

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1985 CA 300D Turbo , 213K mi