What is SAE 10W30 engine oil?

[McEvelyn]

SAE 10W30 is a multi-grade engine oil that provides lubrication and wear reduction, auxiliary cooling, sealing and leak prevention, rust and corrosion protection, as well as shock absorption for the engine. Explanation of engine oil grading: 10W-30 represents its SAE viscosity rating. This value first indicates that the oil is a multi-grade oil. The 'W' stands for WINTER, and the number preceding it denotes the oil's flow performance at low temperatures—the smaller the number, the better the cold-start performance. The number following the 'W' indicates the oil's stability at high temperatures (i.e., its resistance to thinning)—the larger the number, the better the high-temperature stability. Recommended engine oil for different vehicle types: Different manufacturers have varying technical requirements for their engines, leading to different viscosity specifications for engine oils. Japanese and Korean vehicles typically recommend oils with viscosity ratings of 20 or 30, such as SAE 0W-20 or 5W-30. American vehicles generally recommend oils with a viscosity rating of 30, like SAE 5W-30. European vehicles often require oils with a viscosity rating of 40, such as SAE 5W-40. If vehicle owners are unsure, they can directly refer to the recommended oil type specified in their maintenance manual.