American Petroleum Institute. The primary oil and natural gas trade association in the United States. API operates a voluntary licensing and certification program that allows engine oil marketers to use the API Engine Oil Quality Marks if their products meet specific requirements. Service Category SF was first introduced in 1980 for use in gasoline engines and is not suitable for use in engines introduced after 1988.
API has discontinued licensing engine oils against API SF and it is considered to be an obsolete specification.
Engine lubricants claiming to meet API SF are still marketed in some regions around the world. These oils are typically formulated to be SAE 15W-40 or heavier and are unlikely to be suitable for use in the majority of engines. Refer to engine manufacturer recommendations to determine if API SF oils are suitable for use in a specific application.
For more information on API SF, contact your Lubrizol representative.