r/Diesel • u/Language_Puzzled • 5h ago
Question/Need help! The big question... oil
I have a 2016 f250 and have been running Rotella t6 15w40 for the past 2 oil changes. I change the oil every 5k and was possibly thinking of switching to 5w40 for better mileage. I live on the coast of NC and dont see temps get below 25 degrees if it gets that low during one or two mornings of the winter. wanted to hear everyone's thoughts on if I should stay with 15w40 or change to 5w40 for my next change. TIA