what weight oil do you guys run in your motors i have a w201 2.5 should a run a standard diesel oil (15-40) or do you guys use something else im new to this diesel in a car thing. im used to dumping about six or seven gallons in a loader or something like that also does anyone know the cappcity for this motor? thanks

Oil is often a controversial subject. Try a search on the topic if you have a lot of time and are amused by observing normally rational people act otherwise.

In general the 15W-40 oil is fine for warm weather. In cold weather you will want something "lighter." The oil thickens in cold weather, and the starter motor has to operate the oil pump. This more viscous oil condition in a cold start adds a significant load to the starter and it typically slows the cranking speed. Cranking speed is an essential aspect of starting a Diesel in cold weather. So, many use synthetic oils for the winter season and these typically have a 5W-40 or 0W-40 designation.

Most of the controversy with oil surrounds brands and the "dino" vs. synthetic argument. The most important aspect is to use Diesel Engine rated oil - which is designated by the SAE labelling convention with the letter "C" in conjunction with a second letter that progresses alphabetically as the SAE qualification criteria is modified (the "C" stands for compression ignition to distinguish it from "S" for spark ignition engines). Today's Diesel rated engine oils are CH or "later." This designation has nothing to do with the "dino" origin or synthetic origin.

The "dino" vs. synthetic issue boils down to cost. Dino oil is cheaper but you should change it more frequently. For your car, it is likely that Dino oil, with an appropriate oil change interval, is fine. Whether or not synthetic is "better" could be debated, however, it is definitely easier on the starter in cold weather and adds to the probability the car will start in colder weather.

All that said, I use synthetic, Diesel specific oil from Mobil - Delvac 1, 5W-40. I use it all year round. On my 1983 240D I still have difficulty starting in zero degree Fahrenheit weather. But over 10 degrees F is normally no problem - provided the fan belt is tight and the battery is charging (inside snipe at my kids in case they read this).

Good luck,

Jim

__________________
Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)

Click here and start reading. Opinions on oil is like....................

__________________
1987 300TD 309, xxx 2.8.2014 10,000 mile OCI


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Use a quality dino oil or synthetic oil. Brand doesn't really matter as long as its 15W40, 15W50 or 5W40 as well as diesel rated (API classifications CF, CG, CH, CI, and/or CJ).
http://www.whnet.com/4x4/oil.html