Niteo Motor Medic MF2-12PK High Mileage 5-Minute Motor Flush - 30 oz, (Case of 12) Removes gums, varnishes, and sludge from internal parts Releases sticky valves and piston rings, allowing oil to circulate freely Treats engine in 5 minutes Frees up sludge associated with slow city driving Can be easily used by car owners or professional technicians before oil changes