My owners manual dictates that I use only 5w-40 (dino or synthetic) at all times. However, I have found an excellent buy on M1 10w-30 ($3.50/qt) that I would like to take advantage of. I live in Portland Oregon where the temperature rarely drops below 30 deg F even in the coldest months and rarely gets over 90 deg F in the hottest months. Will I have any problems?