An extremely heavy grade of motor oil, typically 50W-20. This oil is used in an automobile when it's on it's last legs and should be replaced. Engine butter does help for a while, but sooner or later the oil burnoff gets so bad hat you are spending as much money one oil as you are on gasoline!!!
I need a reign job on my car, it's smoking like a sonofabitch, i'm gonna pure some engine butter in there, maybe I can get another 3000 miles outof it if I'm lucky.