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. CF-4 was introduced in 1990 for high-speed, four-stroke, naturally aspirated and turbocharged diesel engines.
Oils approved for API CF-4 were designed to be used in place of API CD and CE oils, providing improved control of oil consumption and piston deposits.
API has discontinued licensing diesel engine oils against Service Category CF-4 and it is considered to be a obsolete specification.
Engine lubricants claiming to meet API CF-4 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 CF-4 oils are suitable for use in a specific application.
For more information on API CF-4, contact your Lubrizol representative.