SAE 5W-30 is a type of motor oil that meets the standards set by the Society of Automotive Engineers (SAE). The "5W" indicates its viscosity rating at low temperatures, meaning it flows easily in cold conditions, while "30" refers to its viscosity at higher temperatures, ensuring adequate protection when the engine is hot. This oil is commonly used in many vehicles, providing a balance of performance and fuel efficiency. It helps lubricate engine parts, reduce wear, and improve overall engine function, making it a popular choice for both gasoline and diesel engines.