An oil additive is a substance added to engine oil to enhance its performance and protect engine components. These additives can improve lubrication, reduce friction, and prevent wear and tear, helping to extend the life of the engine. Common types of oil additives include detergents, dispersants, and anti-wear agents. Oil additives can also help in maintaining engine cleanliness by preventing sludge buildup and neutralizing acids formed during combustion. They are often used in both motor oil for vehicles and industrial lubricants to ensure optimal performance in various machinery.