Trying to understand why one would use a heavier than recommended oil arbitrarily.
Because that’s what pappy used in his 238 Detroit and 250 Cummins?
EPA can’t be ruled out, neither can the issues the OEM faces if their engines grenade. It’s not going to help at startup, and if you are maintaining good pressure at idle it’s not going to do anything. If it’s too thick, you may be starving bearings, with no way to know.
Well, they will tell you. Eventually.
