Just as the title implies. I'll be deleting soon and of course can then switch to a more traditional diesel oil. So just wondering. Given the three choices listed (all easily available locally at the same price when on sale) which would the experts here suggest? Stay with the OEM recommended 5w30 viscosity or bump up to a more robust 5w40. And between the two heavier grades, it's there any quantitative difference between them? Or should I just buy and use whichever is on sale cheaper at the time?