Changing your oil and adding ZDDP? For optimum engine efficiency try using Motor Flush before changing your oil. Motor Flush circulates through your engine loosening debris and build up throughout your motor, depositing the debris into your oil filter. Change your oil and filter, add Eastwood ZDDP Oil additive and you are clean, protected and ready to drive.Motor flush works with all tyes of 4-stroke gasoline and diesel engines. ZDDP works with all types of conventional and synthetic motor oils. use with all pre 1989, Non OBD engines.