5w-30 engine oil, just normal auto stuff and the tranni 80w-90 gear oil. nothing special. These engines go forever, I've got a 92 626 and it was used everyday to drive to the farm since new so it's got a ton of hours at full throttle so it smokes like a son of a gun, Can't tell you how many times it has been running low on oil since I've got it, I need to put more oil in almost every timeI take it anywhere and I'm not easy on the engine because it's no good anyway, it sputters, pops and smokes but it refuses to quit.