I replaced the head on my 1993 300SD.
Acutally, I had the engine rebuilt because
of a bent connecting rod (#1 cylinder).
There was no rebuilt engine available.
In the rebuild process, the head was replaced
with a later one with a design change in the
head. Preivously, there was a channel
between the front of the head and the #1
cylinder, which is where I got the oil
for the hydrolock.
If it turns out that you have a bent rod, etc. consider getting a rebuilt engine from
MB as it is warrantied, etc. for, I think,
50K miles or 4 years. The pistons, connecting rods, etc. are supposed to be replaced as a set. The $$$ add up fast.
What is your oil usage? MB said that up to
1 quart per 1,000 miles was ok. It really
wasn't. I change oil at 3,000 with virtually
not usage. Oil consumption will tell you
alot about the problem.