M1 0w30 would be closest as far as Visc and Visc Index, but is the base oil chemistry different? M1 15w50 has a closer matching additive package, as far as us civilians know, but again is the base oil chemistry different?
I honestly can't find 1 quart of M1R to save my life, and I'm not about to buy the whole 6 qts. by mail/internet to make up what the truck uses. My truck uses about 1/2qt./3K miles. In your guys opinion which M1 SS would be best to top off with?
I'm about to trailer a 2000 lb. bass boat from Philly to the St. Lawrence River, about 350 miles each way, no easy task on any engine with the mountains that RULE NE Pennsy. I wanted to do a UOA on the M1R "unmolested" but I can't find one quart of M1R anywhere. Has anyone seen this oil anywhere in the Philly area? thanks