Originally Posted By: ProfPS
I am interested to know which dino brand do you use in your summer dino/winter syn OCI plan?
That's a loaded question.
As others have pointed out, it depends upon the application. Something like my G, still under warranty and requiring SM/GF-4 or better 5w-30, it's pretty easy. I use PYB all year. I could use any SN/GF-5 conventional or synthetic and rest easy.
The old Audi had different oil recommendations, as does my old F-150. For the Audi, I tended to run Mobil Delvac 15w-40 in the summer, and either a conventional 10w-30 or 5w-30 in the winter, or a synthetic 0w-40 or 5w-40 in winter (or all year).
The old truck spends all its time outside, so I could, theoretically, go to a 0w-30 HDEO in the winter, and a 10w-30 HDEO in the summer (if I wanted to save cash), or stick with the 0w-30 all year. To save cash, I could also use up my 15w-40 stash for summer usage.
For the G, I don't worry as much. It recommends the same thing regardless of weather, and I don't consider higher ZDDP levels like I might want to do with the old truck. If I decide ZDDP isn't an issue, I'd run 5w-30 PCMO in both all year round.