The new,improved (?) M1 15w50 jugs I bought last week have no diesel designation that I,in my very limited wisdom,can recognize. New Jug says:API,SN,SM,SL and ACEA A3/B3,A3/B4. Are these ACEA ratings for diesel as well as gasoline engines? The old jug says SM,SL/CF and that is it. I have been...