I am changing the Cylinder Head Gasket on my 1989 Mercedes 300e.

Research and Plan,

Mercedes-Benz E-Class Owner's Bible

MERCEDES SHOP MANUAL SERVICE REPAIR BOOK W124, 300E 1985-1995

Estimate costs and time
$800 to $1000 in 2 months
Est machine shop $350

Design work procedures and work area layout;
work tables
storage for used parts
storage for new parts
storage for tools
https://docs.google.com/drawings/d/1VqYZ7arqG1lp_jaA4u_BBvEf41265TjPjj1zwPXlqc0/
With locked Roughneck Jumbo Storage totes under the table

Create chart to record progress and measurements

Clean engine, take time
Record everything as parts are removed,
Take lots of pictures
Inspect, clean good parts, label, store, and index
Clean with paper towels and coffee filters
Coat with oil, http://www.royalpurpleconsumer.com/products/max-tuff-synthetic-assembly- lubricant/

Order new parts
Rebuild cylinder head at local machine shop
Replace worn engine parts with new ones
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, but 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 headgasket 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."

1) As someone pointed out to me, many people are not aware of the fact the chain tensioner has to be run all the way through and re introduced through the back side, essentially resetting it to min tension extension. Replace the chain tensioner while your doing this, you have 95% of the work you need to do for that done anyway, and it is inexpensive.

2) Watch the dowel pins for the intake. They often fall out during removal - True

3) Make sure you use some silicone to help the timing cover gasket seal. I tried to clean the surfaces thouroughly and use the gasket alone...it leaked anyway. Siliconed the ends of the gasket a bit when I removed the timing cover the second time - no leaks (and I use Mobil 1).

4) When you pull the head, check which cyllinders have been blowing by back into the intake. Replace those injector nozzles. My car still idled a bit rough even after the valve job - until I replaced those injectors. Now it's smooth as silk.

Rebuild used parts and reconditioned

Parts needed:

Cylinder head gasket kit
Cylinder head bolts ans washers
Rebuild cylinder head or have old one machined
Fuel Injection seals
Valve cover gasket
Bags with labels
Timing chain guides
Front cam gear seal
EGR valve gasket

Tools