So finally after 433k miles I am seeing slight symptom of failing headgasket. I have a small oil leak at the front passenger side of the engine, just right under the timing cover. I checked the U shaped timing cover and even replaced it a few weeks ago, but there was still oil leaking and the new seal was bone dry. tracked the leak to the front of the block/head. I have read the how to article for the w124 on this forum and just went out and purchased the 12 mm xzn bit. I have a new water pump coming and I have valve cover seal, even though I just replaced that about a month ago, and I have all new hoses and seals for the entire cooling system. Anything else I need other than the cyclinder head gasket/bolts or anything else I should replace? Valve stem seals were replaced 3/2015 @ 360k miles.....maybe I should do those too? Also, I have somewhat of a unique situation. I actually have another m103 engine sitting in my garage. So what I was thinking of doing was disassembling that one before diving into the one on my car. Then I can send that head out to be machined and when I get it back I can just take off mine, clean up the block, and put the other one on. I welcome any tips and advice anyone can offer. Thanks.

__________________

1990 190E 3.0L