I never have and generally do not mix motor oils, but the lack of good deals and my ample oil stash has me thinking that I should just use what I've got for this next change. If you guys had to select a 6-qt mix of oil from the following list, what would you choose? Application is an '08 Dodge 4.7 with M1 oil filter for an 8k OCI (2 months or so) in Northern/Central CA. What I've got: Mobil 1 0w20 AFE - 5 qts Mobil 1 5w20 - 4 qts Penn. Ultra 5w20 - 1 qt Mobil 1 0w30 AFE - 2 qts Penn. Ultra 5w30 - 3 qts Mobil 1 5w30 - 1 qt Mobil 1 5w30 HM - 2 qts Mobil 1 0w40 - 16 qts Mobil 1 5w40 TDT - 9 qts Mobil 1 15w50 - 8 qts Amsoil 20w50 - 1 qt I was actually just thinking of using 5 qts of the M1 0w20 and throwing in the Amoil 20w50 since it has been sitting around a few years...is this a bad idea? Should I stick with a 20wt or 30wt for all 6 quarts? Or does it not even matter?