Theoretically. This crossed my mind as I was looking at my oil stash spreadsheet(nerd!). If I were to mix my most dense oil, Valvoline Premium Blue 15w40(.880) with my least dense oil, RGT 0w-20(.833) would they mix homogeneously our would they separate if left sit for a period. Just a thought. I wouldn't mix these oils unless the virus has completely taken over civilization and I had to!