As we beat this dead horse I remain curious regarding the manufacturer’s climate specific recommendations regarding oil. Whenever I have taken the time to dig beyond the obvious I have found that manufacturers have temperature/viscosity charts that are relatively equal with respect to the most popular viscosity grades. I recall a Lexus chart that clearly specified straight 30 weight oil when temperatures were never below 30F and OW20 was actually not specified unless the temperature could drop below 0F while not exceeding some not so extreme high temperature. Why don’t the manufacturers make their climate specific recommendations available to the public as they did for so many years? I recall the 1950s Willys manual specifying diluting 20W oil with kerosene when temperatures dropped below 0*F. As I opined earlier here, if the temperature is mild 5W30 would most likely be the better choice and 10W30 better still.