What Does Engine Oil Model Number Mean?

[DeDante]

Engine oil model numbers consist of two parts: classification and viscosity specifications. The oil model number typically indicates viscosity and quality. Detailed explanation: The viscosity of lubricating oil is often identified using SAE grades, where SAE stands for the Society of Automotive Engineers. More detailed information is as follows: 1. On the outer packaging of engine oil, you will often see SAE and API. SAE is the abbreviation for the Society of Automotive Engineers, and API stands for the American Petroleum Institute. The number following SAE indicates the oil's viscosity value, while the number following API indicates the oil's quality grade. 2. 10W-40 is its SAE standard viscosity value. This viscosity value first indicates that the oil is a multi-grade lubricant. The 'W' stands for WINTER, and the number before the W represents the pour point temperature, simply put, the freezing point temperature. 10W oil corresponds to a freezing point temperature of -25°C, while other common grades include 0W at -35°C, 5W at -30°C, and 15W at -20°C. The number after the W represents the oil's kinematic viscosity at 100°C, with higher numbers indicating higher viscosity. 40 means the kinematic viscosity standard at 100°C is between 12.5mm2/s and 16.3mm2/s, and it absolutely does not mean, as some folk interpretations suggest, that it can be used below 40°C. It's important to know that engine operating temperature is not necessarily determined by ambient temperature; prolonged high-RPM driving can easily raise engine temperature to 100°C, yet there are no lubricants with a 100 rating.