M1's 0w40 carries a light diesel spec
Yeah, well ....... true enough ..... but then, unless I misunderstood the OP wasn't asking for a general oil recommendation for his heavy-duty Class 8 semi tractor .....
he was asking for 0w40 oil recommendation for a CUT .....
and can't really handle the soot dispersant capability's a currant CJ-4 oil can, i really would stick with a 5w40 much better choice in diesel applications and will flow fine in them temps.
Yup ... newer ain't always better tho' ..... given a particular application.
CJ-4 oils were specifically formulated to meet compatibility requirements with particular emission devices (specifically diesel particulate filters) used on-road vehicles:
API CJ-4 Facts
In order to meet these compatibility requirements it appears some tradeoffs were made (despite what API and oil refiners/formulators might claim)
FWIW, M1 0w40 was the factory-fill from Mercedes on my OM 647 engine (2.7L, 154 HP) ........ and Mercedes approves it for use with extended drain intervals.
I suspect that if M1 0w40's soot dispersant capabilities were lacking, Mercedes would not be so inclined.
I do run extended drain intervals, which on average have ranged on average from 13K to 18K miles, although I have went much longer when I had the bypass filtration set up on it.
Personally, I currently have 345,000 miles on the vehicle using
only this oil .... running in winter and summer conditions, ranging from south & west Texas (Laredo/El Paso), Arizona (Nogales, Tuscon, Phoenix) to Minnesota, Michigan (UP & LP), Ontario (as far up as Sudbury), and Quebec ..... operating in temps approaching 120 degrees F in the summer, and -25 below zero F in the winter .....
and have a number of friends, doing the same thing, with the same vehicle/motor/oil ..... with vehicle mileages ranging from 400K to over 800K ..... on original engines .....
My Blackstone UOA's speak for themselves, in terms of the performance of the product - note that the mileage on the
current oil sump, as of the time of the following oil analysis, is 47,625 miles. Make up oil reported is cumulative (6.75 total quarts used over 47K+ miles):