VERY nice car...if you like the car it is worth fixing. IF it needs an engine I'd consider using a 240D from a 74-76 due to additional power.

Is a head gasket available, I don't know but would ask the MBZ Classic Center.

I think that engine has an oil sump bath injection pump. Look for a cap that says OEL on top of the pump. Change the ancient oil in there otherwise the pump may seize.

Adjust the valves.

Coal like oil is perfectly normal even on a fresh engine after an oil change. Use C rated diesel oil, Rotella, Delo etc.

Make sure it can breathe.

Chemical soak the rings and drive it hot and hard. Run it full throttle uphills and let it coast down hill repeatedly to work the rings free after a soak.

Use fresh diesel fuel.

Compression test is a great idea, adjust the valves and run it hard first. If it starts easily the rings should be ok except for the oil rings possibly being clogged (ring soak).

Again that is a SUPER nice car, if you like it fix it but remember a 190D in great shape is S L O W. Consider a later 240D engine

Good luck!!!

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