I would assume a trucker can put 3000 mi/week on the old rig, I would think the old 3000 mi standard might be overkill, but then again it is a engine and does need maintance. Even the newer 7500 mi limit seems a bit excessive. Then again these are for autos, and gasoline engines
So what are the recommended oil change interval on those rigs? and what about disel autos?
For some diesel engines, they do a periodic lab analysis of a sample of the engine’s oil, and replace the oil when it no longer passes their tests.