Gasoline Engine Oil Additive Package – SF/SL/SM/SN

Gasoline engine oil additive packages, such as SF, SL, SM, and SN, refer to different specifications and performance levels set by the American Petroleum Institute (API) for motor oils used in gasoline-powered engines. These specifications define the quality and characteristics of the oil, ensuring it provides the necessary protection and performance for modern engines.

Here's a breakdown of these specifications:

SF (Obsolete): SF is an older specification that was introduced by the API in 1980. It provided basic engine protection for engines of its time. However, due to advancements in engine technology and emission control systems, more advanced specifications have been introduced.
SL: SL is a specification introduced in 2001 and represents an improvement over SF. Oils meeting the SL specification offer better protection against oxidation, deposit formation, and wear. They are designed to work with engines equipped with hydraulic valve lifters, which require proper oil flow and pressure.
SM: SM is an API specification introduced in 2004. Oils meeting the SM specification provide improved protection for engines with higher operating temperatures and increased power density. They also help control sludge and varnish formation, which can occur under demanding operating conditions.
SN: SN is a specification introduced in 2010 and represents the current standard for gasoline engine oils. Oils meeting the SN specification are designed to provide enhanced protection against wear, deposits, and oil consumption. They are formulated to be compatible with modern emissions control systems and to address the needs of modern engines, including those with turbochargers.
It's important to note that as newer specifications are introduced, they generally provide better protection and performance for modern engines. When choosing an engine oil, it's recommended to use the oil grade and specification recommended by the vehicle manufacturer to ensure optimal engine performance and longevity.

Additionally, engine oil additives are often included in the formulation to further enhance specific properties of the oil, such as detergency, anti-wear protection, and viscosity stability. These additives help the oil meet the required performance standards set by the API specifications.