PeachParts Mercedes-Benz Forum - View Single Post - Coolant Flush Notes -- De-Oiling Surprises

dlssmith · #15 09-16-2010, 05:22 PM

FWiW, I have looked inside a lot of different diesel cooling systems in my life in farm tractors and trucks, including the one in my old 87 300D with a 603 engine. I don't recall ever seeing as much oil in any other system as there was in the 603. I contemplated cleaning it, but never did. I believe oil accumulated in the coolant as a result of blow by. I don't have any other explanation for it. There was no coolant in the oil - I had it tested a couple of times to be sure. And the oil use of that engine was almost nothing.
I put a new expansion tank on and after a time, the black sludge began to show on the walls of the new tank. The car didn't over heat no matter how hot and with the a/c running. My dad said to leave it and not worry about it and maybe it was lubricating the water pump. I do believe the oil would protect the aluminum parts quite nicely.