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API Engine Oil Service Categories
What is the API Engine Oil Program?
API’s Engine Oil Licensing and Certification System (EOLCS) is a voluntary licensing and certification program that authorizes engine oil marketers that meet specified requirements to use the API Engine Oil Quality Marks. Launched in 1993, API’s Engine Oil Program is a cooperative effort between the oil and additive industries and vehicle and engine manufacturers Ford, General Motors, and Fiat Chrysler and those represented by the Japan Automobile Manufacturers Association and the Truck and Engine Manufacturers Association. The performance requirements and test methods are established by vehicle and engine manufacturers and technical societies and trade associations such as (ASTM), (SAE), and the American Chemistry Council (ACC).
The Engine Oil Program is backed by monitoring and enforcement program that ensures licensees adhere to program requirements. This includes running physical, chemical, and performance tests on licensed engine oils and verifying that the API-registered Marks are properly displayed on containers and convey accurate information to consumers.
API Service Cateogies
There are four classifications that make up the API Engine Oil Program, ILSAC, Gasoline, Diesel C Category & Diesel F Category. See below for the current categories for each classification:
ILSAC Standard For Passenger Car Engine Oils
Name | Status | Service |
| GF-6A | Current | Introduced in May 2020, designed to provide protection against low-speed pre-ignition (LSPI), timing chain wear protection, improved high temperature deposit protection for pistons and turbochargers, more stringent sludge and varnish control, improved fuel economy, enhanced emission control system protection and protection of engines operating on ethanol-containing fuels up to E85. |
| GF-6B | Current | Applies only to oils having an SAE viscosity grade of 0W-16. Introduced in May 2020, designed to provide protection against low-speed pre-ignition (LSPI), timing chain wear protection, high temperature deposit protection for pistons and turbochargers, stringent sludge and varnish control, improved fuel economy, emission control system protection and protection of engines operating on ethanol-containing fuels up to E85. |
| GF-5 | Obsolete* | Use GF-6A where GF-5 is recommended. |
| GF-4 | Obsolete | Use GF-5 where GF-4 is recommended. |
| GF-3 | Obsolete | Use GF-5 where GF-3 is recommended. |
| GF-2 | Obsolete | Use GF-5 where GF-2 is recommended. |
| GF-1 | Obsolete | Use GF-5 where GF-1 is recommended. |
*Obsolete on May 1, 2021
Gasoline Engines
Note: The letters “SI”, “SK”, and “SO” have been omitted from the sequence of letter designations for API Service Categories because of their common association with other organizations or systems. If an automotive owner’s manual calls for an API SN oil, an API SP oil will provide full protection.
Category | Status | Service |
| SP | Current | Introduced in May 2020, designed to provide protection against low-speed pre-ignition (LSPI), timing chain wear protection, improved high temperature deposit protection for pistons and turbochargers, and more stringent sludge and varnish control. API SP with Resource Conserving matches ILSAC GF-6A by combining API SP performance with improved fuel economy, emission control system protection and protection of engines operating on ethanol-containing fuels up to E85. |
| SN | Current | For 2020 and older automotive engines |
| SM | Current | For 2010 and older automotive engines. |
| SL | Current | For 2004 and older automotive engines. |
| SJ | Current | For 2001 and older automotive engines. |
| SH | Obsolete | CAUTION: Not suitable for use in most gasoline-powered automotive engines built after 1996. May not provide adequate protection against build-up of engine sludge, oxidation, or wear. |
| SG | Obsolete | CAUTION: Not suitable for use in most gasoline-powered automotive engines built after 1993. May not provide adequate protection against build-up of engine sludge, oxidation, or wear. |
| SF | Obsolete | CAUTION: Not suitable for use in most gasoline-powered automotive engines built after 1988. May not provide adequate protection against build-up of engine sludge. |
| SE | Obsolete | CAUTION: Not suitable for use in most gasoline-powered automotive engines built after 1979. |
| SD | Obsolete | CAUTION: Not suitable for use in most gasoline-powered automotive engines built after 1971. Use in more modern engines may cause unsatisfactory performance or equipment harm. |
| SC | Obsolete | CAUTION: Not suitable for use in most gasoline-powered automotive engines built after 1967. Use in more modern engines may cause unsatisfactory performance or equipment harm. |
| SB | Obsolete | CAUTION: Not suitable for use in most gasoline-powered automotive engines built after 1951. Use in more modern engines may cause unsatisfactory performance or equipment harm. |
| SA | Obsolete | CAUTION: Contains no additives. Not suitable for use in most gasoline-powered automotive engines built after 1930. Use in modern engines may cause unsatisfactory performance or equipment harm. |
Diesel Engines – C Category
Note: For diesel engines, the latest category usually – but not always – includes the performance properties of an earlier category.
Category | Status | Service |
| CK-4 | Current | API Service Category CK-4 describes oils for use in high-speed four-stroke cycle diesel engines designed to meet 2017 model year on-highway and Tier 4 non-road exhaust emission standards as well as for previous model year diesel engines. These oils are formulated for use in all applications with diesel fuels ranging in sulfur content up to 500 ppm (0.05% by weight). However, the use of these oils with greater than 15 ppm (0.0015% by weight) sulfur fuel may impact exhaust aftertreatment system durability and/or oil drain interval. These oils are especially effective at sustaining emission control system durability where particulate filters and other advanced aftertreatment systems are used. API CK-4 oils are designed to provide enhanced protection against oil oxidation, viscosity loss due to shear, and oil aeration as well as protection against catalyst poisoning, particulate filter blocking, engine wear, piston deposits, degradation of low- and high-temperature properties, and soot-related viscosity increase. API CK-4 oils exceed the performance criteria of API CJ-4, CI-4 with CI-4 PLUS, CI-4, and CH-4 and can effectively lubricate engines calling for those API Service Categories. When using CK-4 oil with higher than 15 ppm sulfur fuel, consult the engine manufacturer for service interval recommendations. |
| CJ-4 | Current | For high-speed four-stroke cycle diesel engines designed to meet 2010 model year on-highway and Tier 4 non-road exhaust emission standards as well as for previous model year diesel engines. These oils are formulated for use in all applications with diesel fuels ranging in sulfur content up to 500 ppm (0.05% by weight). However, the use of these oils with greater than 15 ppm (0.0015% by weight) sulfur fuel may impact exhaust aftertreatment system durability and/or drain interval. API CJ-4 oils exceed the performance criteria of API CI-4 with CI-4 PLUS, CI-4, CH-4, CG-4 and CF-4 and can effectively lubricate engines calling for those API Service Categories. When using CJ-4 oil with higher than 15 ppm sulfur fuel, consult the engine manufacturer for service interval. |
| CI-4 | Current | Introduced in 2002. For high-speed, four-stroke engines designed to meet 2004 exhaust emission standards implemented in 2002. CI-4 oils are formulated to sustain engine durability where exhaust gas recirculation (EGR) is used and are intended for use with diesel fuels ranging in sulfur content up to 0.5% weight. Can be used in place of CD, CE, CF-4, CG-4, and CH-4 oils. Some CI-4 oils may also qualify for the CI-4 PLUS designation. |
| CH-4 | Current | Introduced in 1998. For high-speed, four-stroke engines designed to meet 1998 exhaust emission standards. CH-4 oils are specifically compounded for use with diesel fuels ranging in sulfur content up to 0.5% weight. Can be used in place of CD, CE, CF-4, and CG-4 oils. |
| CG-4 | Obsolete | CAUTION: Not suitable for use in most diesel-powered automotive engines built after 2009. |
| CF-4 | Obsolete | CAUTION: Not suitable for use in most diesel-powered automotive engines built after 2009. |
| CF-2 | Obsolete | CAUTION: Not suitable for use in most diesel-powered automotive engines built after 2009. Two-stroke cycle engines may have different lubrication requirements than four-stroke engines, so the manufacturer should be contacted for current lubrication recommendations. |
| CF | Obsolete | CAUTION: Not suitable for use in most diesel-powered automotive engines built after 2009. Later “C” category oils are usually suitable or preferred for diesel automotive engines for which “CF” oils were specified. Older equipment and/or two-stroke diesel engines, especially those calling for monograde products, may however require “CF” category oil. |
| CE | Obsolete | CAUTION: Not suitable for use in most diesel-powered automotive engines built after 1994. |
| CD-II | Obsolete | CAUTION: Not suitable for use in most diesel-powered automotive engines built after 1994. |
| CD | Obsolete | CAUTION: Not suitable for use in most diesel-powered automotive engines built after 1994. |
| CC | Obsolete | CAUTION: Not suitable for use in most diesel-powered engines built after 1990. |
| CB | Obsolete | CAUTION: Not suitable for use in most diesel-powered engines built after 1961. |
| CA | Obsolete | CAUTION: Not suitable for use in most diesel-powered engines built after 1959. |
Diesel Engines – F Category
Note: For diesel engines, the latest category usually – but not always – includes the performance properties of an earlier category.
Category | Status | Service |
| FA-4 | Current | API Service Category FA-4 describes certain XW-30 oils specifically formulated for use in select high-speed four-stroke cycle diesel engines designed to meet 2017 model year on-highway greenhouse gas (GHG) emission standards. These oils are formulated for use in on-highway applications with diesel fuel sulfur content up to 15 ppm (0.0015% by weight). Refer to individual engine manufacturer recommendations regarding compatibility with API FA-4 oils. These oils are blended to a high temperature high shear (HTHS) viscosity range of 2.9cP–3.2cP to assist in reducing GHG emissions. These oils are especially effective at sustaining emission control system durability where particulate filters and other advanced aftertreatment systems are used. API FA-4 oils are designed to provide enhanced protection against oil oxidation, viscosity loss due to shear, and oil aeration as well as protection against catalyst poisoning, particulate filter blocking, engine wear, piston deposits, degradation of low- and high-temperature properties, and soot-related viscosity increase. API FA-4 oils are not interchangeable or backward compatible with API CK-4, CJ-4, CI-4 with CI-4 PLUS, CI-4, and CH-4 oils. Refer to engine manufacturer recommendations to determine if API FA-4 oils are suitable for use. API FA-4 oils are not recommended for use with fuels having greater than 15 ppm sulfur. For fuels with sulfur content greater than 15 ppm, refer to engine manufacturer recommendations. |
