To ALL of you who helped me make my decision final... You guys really helped me, and thanks for all your time. After reading all 10 comments to my question about oil consumption, I decided to go with Pennz. High Mil. 10w-30. I'm going to change oil today. Anotyher question: Pennz HM 10/30 is 12 cSt, Pennz. HM 10/40 is 15.5 cSt... If I mix 1 qt of 10/40 with 4 qts of 10/30 what weight would it have? is it even ok to do it?