wassup fellaz...
I was talking with my mechanic the other day while he was teaching me how to do oil changes on my 300D 78 and i've notice that the oil was completely black with little specks. I ask him if the oil was supposed to be this black and he said yes..."since diesle engines run on compression, the engine is typically hotter than a conventional gas engine and therefore would turn oil darker and sometimes even burn off oil." could anyone enlighten me on this topic..I find it somewhat disturbing to my engine oil like this. Maybe this is what causes my engine to be distinctively louder than other 300D of the same year....dont know????

Every diesel I have ever worked on had oil so black you couldn't wash it off your hands, it had to wear off. That is normal for a diesel, you can change the oil and drive around the block and the new oil will be black.

As far as diesels running hotter than gas engines, I think that is incorrect. I believe diesels run cooler overall. The oil turns black because of the oily soot byproduct of the fuel. Diesel fuel is just lighter oil and your engine will run on motor oil, which is what happens when you start burning oil bad. A gas engine will stop running due to fouled plugs long before a diesel will quit running.

__________________
Mike Tangas
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72

'02 CLK320 Cabriolet - wifey's mid-life crisis

2012 VW Jetta Sportwagon TDI...at least its a diesel

Non illegitemae carborundum.

I have the same situation on a 1977 300D. It has been that way since it was purchased. It has 170,000 miles and runs great.

Feedback from mechanics has been don't worry about it. It is due primarily to the relative "uncleanliness" of diesel engines. Being the trusting soul that I am I have bought the story so far.

JCD

The same black stuff that comes out the tailpipe also gets in the oil and turns it black quickly. Diesel rated oil has additives to control this soot.

What has me concerned here is not the black oil. That is normal as the guys have been saying. However the little specks you mentioned may not be normal. Are they silver colored specks? If so, thay could be aluminum, steel, or bearing material indicating you may have a major problem in the engine. Please explain the specks some more.