Thank you for providing the full gambit of information, I will be running the 5w30 Costco brand after I run out of the Mobil 1. Just wanted to do what is right, so much information on the interweb.
Was forced by a Kia Soul to find a replacement for my 97 F250 7.3L, found this cherry at a local...
Ford OEM Spec is 5w-20, not -30, so I am not inclined to increase the viscosity of the oil at operating temp, only have 65k miles on it. I know the 0w is rated at -35 deg. F starting temp, and the 5w is rated at -30 deg. F. and again in FL we never even approach those conditions.
Looking at available information online, I should be able to use 0w-20 as a replacement. Currently using Mobil 1 synthetic 5w-20, have option to use a full synthetic Costco brand 0w-20 at a significant cost savings. This is in central FL where we rarely see temp lower than 32 deg. F, just do not...