-- OK I see your point re. CAFE numbers, didn't see that at first. 6 months is still along time between oil changes. Cold starts and short trips put a LOT of gas in the oil. If you don't do a long run to vaporise this gas ( and water due to condensation) You are not lubricating you engine properly. Just remember that oil is cheap. Motors are not. Why would you ever take the chance? Geoff.