Engine Oil Booster and engine treatment additives get used up and become less and less effective over time. Even metal bonding agents wear off between sliding surfaces and under pressure. It is necessary to replenish the additives to fortify your oil.Gars has an advanced multi-functional synthetic formula that not only treats the metal but fortifies the motor oil as well. Use with Complete Confidence and Peace of Mind. Gars advanced formula is compatible with petroleum, mineral, and synthetic motor oils and oil additives. Perfect for new or older cars. Will not void new vehicle warranties.