Detergency

· Most engine oils contain detergent and dispersant additives to prevent dirty particular produced by incomplete combustion from accumulating and plating metal surface.

Anti-rust Property · Water may seep into the lubricating system and cause rusting of machine parts. · Rust particles can act as catalyst to accelerate the oxidation of the oil. · Anti-rust additives can be absorbed onto metal surface and prevent moisture from coming into contact with the metal, thus preventing rusting.

Corrosion Inhibition

· Acidic materials in oil can cause corrosion of machine parts.

· Corrosion can be minimized by the additives of corrosion inhibitor that reacts with metal to form a protective layer separating the acidic materials and the metal.

Anti-foaming Property

· Foaming reduces the lubricity of oil because the air bubbles in the foam will create a barrier between the oil and the metal surface.

· Foam can also produce resistance to the movement of machine parts.

· In a hydraulic system, foam will reduce the cohesive power of the oil and cause the hydraulic pressure to drop.

· Good lubricating oil will not foam easily and can disperse foam quickly. Anti-foam additives can help to reduce the foaming tendency of oil.