On the first oil change, since i've purchased my old 240d, the oil was instantly black. Now, I realize on diesels that your oil doesn't stay clear for long, but I literally drove it less than a mile, and I couldn't tell the oil had been changed at all. Is this common? I thought about doing an engine flush, but in my experience with old cars, it seems to destroy the old seals, and they leak afterwards. What are everyone's thoughts?

 

As always, Forcedinduction, thank you for the information! I was a bit concerned - used to cummins, and they seem to stay clear for a day or two - didn't know what to expect on the mercedes.

 

Some shorter interval changes could lessen the black oil with no prior history of change intervals done. Even though the oil may be black it still can preform it's duties. A flush of a filthy engine could plug some oil ports in the end cause more harm then good.

 

Would Delo 15w-40 be good to run in my car?
'82 300D Turbo

 

Basicly any oil today that meets the manufactors spec's will do fine when changed properly. I personely run mobil 1 for cold winter starts

 

A friend (diesel mechanic) looked at the dipstick, and I didn't say anything about it's color. He looked at me and said, "it's been awhile since this has been changed." My reply was, "not that long...about 30 miles ago." Yeah, that's how black it was...I thought about an engine flush, but had a bad experience with leaking seals afterwards on another high-mileage truck, so I'm just going to change it more often at first. I went ahead and bought 2 extra bosch oil filters for just such occasions.

 

Most all diesel engines have black oil immediately after driving a few miles, but not all. My company has a 70D JD Excavator. It takes almost 50 hours running for the oil to change appreciably. Of all the diesels we run this is the only one I can say that about.
Your Mechanic I suspect is a "gasoline" engine mechanic, but not well versed in diesels. No disrespect intended, just a thought.

 

No offense taken at all - but no, he's a caterpillar diesel mechanic, and really knowledgeable. I might have said this, but he thinks it's sludge accumulation over time, and lack of proper service. He's not trying to sell me anything - he just works on stuff I need to fix occasionally. His take on it was basically just as was suggested here - change the oil more often for the first couple of oil changes, and maybe drop the oil pan and clean it out really well, and then refill it. We'll see how it goes...I'd already thought about doing that, just to replace the gasket.

 

One thing you can do is switch to a full synthetic. It costs more, but synthetics are specially designed to encapsulate contaminants and carry them out of your engine when you change the oil. With regular dino oil those same contaminants are usually left behind burned to any surface that will hold them.

 

New formulations of engine oil don't contain enough zinc (ZDDP) to properly lubricate the top end of the Mercedes-Benz OM engine. Stick with traditional 15W-40 such as Rotella or Delvac to ensure proper engine lubrication. If you're concerned about cold weather starts you can use a lighter weight "high mileage" formulation such as that offered by Valvoline, for example, which contains an elevated level of ZDDP versus their standard multi-grade product.