why do you think there is a crack ? the coolant leak is due to the poor design of the head-gasket which is well documented.

in any case, take the head to a shop to be checked. the shop SHOULD have experience with m104 heads. I was told be a mercedes repair shop in town (when i was doing mine) that a lot of machine shops go overboard while straightening the head (shaving too much off). This is not recommended for these heads, so make sure the machine shop people know what they are doing...

If i were you, i would call a reputable mercedes repair shop and ask them where they send their heads for machining. that is what i did,,,,

good luck!

__________________
1993 300E, 2.8 M104 .....