Motor oil is a lubricating oil used in internal combustion engines to reduce friction and wear on moving parts. Different types of motor oil are formulated for a variety of purposes, including gasoline and diesel engines, passenger cars, trucks, motorcycles, and other vehicles. The main functions of motor oil are to lubricate engine parts, clean the engine by suspending small particles, dissipate heat generated by the engine, and seal piston rings to prevent compression loss. The right type and viscosity grade of motor oil is crucial for optimal engine performance, fuel efficiency, and engine life. Motor oil undergoes regular changes and filter replacements to maintain its lubricating properties and keep engines running smoothly.