For more than 75 years, API has led the development of petroleum and petrochemical equipment and operating standards. These represent the industry’s collective wisdom on everything from drill bits to environmental protection and embrace proven, sound engineering and operating practices and safe, interchangeable equipment and materials. API maintains more than 500 standards and recommended practices. On this site we introduce API's most important lubricant standards.
| "S" | Status | Service Gasoline Engines |
|---|---|---|
| SN | Introduced in October 2010 | Introduced in October 2010 for 2011 and older vehicles, designed to provide improved high temperature deposit protection for pistons, more stringent sludge control, and seal compatibility. API SN with Resource Conservingmatches ILSAC GF-5 by combining API SN performance with improved fuel economy, turbocharger protection, emission control systemcompatibility, and protection of engines operating on ethanol-containing fuels up to E85. |
| SM | Introduced on 30 November 2004 | Category SM oils are designed to provide improved oxidation resistance, improved deposit protection, better wear protection, and better low-temperature performance over the life of the oil. Some SM oils may also meet the latest ILSAC specification and/or qualify as Energy Conserving. They may be used where API Service Category SJ and SL earlier categories are recommended. |
| SL | 2001 Gasoline Engine Service | Category SL was adopted to describe engine oils for use in 2001. It is for use in service typical of gasoline engines in present and earlier passenger cars, sports utility vehicles, vans and light trucks operating under vehicle manufacturers recommended maintenance procedures. Oils meeting API SL requirements have been tested according to the American Chemistry Council (ACC) Product Approval Code of Practice and may utilize the API Base Oil Interchange and Viscosity Grade Engine Testing Guidelines. They may be used where API Service Category SJ and earlier categories are recommended. |
| SJ | 1997 Gasoline Engine Service | Category SJ was adopted in 1996 to describe engine oil first mandated in 1997. It is for use in service typical of gasoline engines in present and earlier passenger cars, vans, and light trucks operating under manufacturers recommended maintenance procedures. Oils meeting API SH requirements have been tested according to the American Chemistry Council (ACC) Product Approval Code of Practice and may utilize the API Base Oil Interchange and Viscosity Grade Engine Testing Guidelines. They may be used where API Service Category SH and earlier categories are recommended. |
| SH | Obsolete | For model year 1996 and older engines. |
| SG | Obsolete | For model year 1993 and older engines. |
| SF | Obsolete | For model year 1988 and older engines. |
| SE | Obsolete | For model year 1979 and older engines. |
| SD | Obsolete | For model year 1971 and older engines. |
| SC | Obsolete | For model year 1967 and older engines. |
| SB | Obsolete | For older engines. Use only when specifically recommended by the manufacturer. |
| SA | Obsolete | For older engines; no performance requirement. Use only when specifically recommended by the manufacturer. |
| "F" | Status | Service Diesel Engines |
|---|---|---|
| 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. |
| "C" | Status | Service Diesel Engines |
|---|---|---|
| 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 - 2006 | Introduced in 2006 for high-speed four-stroke engines. Designed to meet 2007 on-highway exhaust emission standards. CJ-4 oils are compounded for use in all applications with diesel fuels ranging in sulphur content up to 500ppm (0.05% by weight). However, use of these oils with greater than 15ppm sulfur fuel may impact exhaust after treatment system durability and/or oil drain intervals. CJ-4 oils are effective at sustaining emission control system durability where particulate filters and other advanced after treatment systems are used. CJ-4 oils exceed the performance criteria of CF-4, C-4, AH-4 and C-4. |
| CI-4 Plus | Current - 2004 | Used in conjunction with API C-4, the " CI-4 PLUS" designation identifies oils formulated to provide a higher level of protection against soot-related viscosity increase and viscosity loss due to shear in diesel engines. Like Energy Conserving, CI-4 PLUS appears in the lower portion of the API Service Symbol "Donut." |
| CI-4 | Severe-Duty Diesel Engine Service | The CI-4 performance requirements describe oils for use in those high speed, four-stroke cycle diesel engines designed to meet 2004 exhaust emission standards, to be implemented October 2002. These oils are compounded for use in all applications with diesel fuels ranging in sulfur content up to 0.05% by weight. These oils are especially effective at sustaining engine durability where Exhaust Gas Recirculation (EGR) and other exhaust emission componentry may be used. Optimum protection is provided for control of corrosive wear tendencies, low and high temperature stability, soot handling properties, piston deposit control, valve train wear, oxidative thickening, foaming and viscosity loss due to shear. CI-4 oils are superior in performance to those meeting API CH-4, CG-4 and CF-4 and can effectively lubricate engines calling for those API Service Categories. |
| CH-4 | Severe-Duty Diesel Engine Service | This service oils are suitable for high speed, four-stroke diesel engines designed to meet 1998 exhaust emission standards and are specifically compounded for use with diesel fuels ranging in sulfur content up to 0.5% weight. CH-4 oils are superior in performance to those meeting API CF-4 and API CG-4 and can effectively lubricate engines calling for those API Service Categories. |
| CG-4 | Obsolete | This category describes oils for use in high speed four-stroke-cycle diesel engines used in both heavy-duty on-highway (0.05% wt sulfur fuel) and off-highway (less than 0.5% wt sulfur fuel) applications. CG-4 oils provide effective control over high temperature piston deposits, wear, corrosion, foaming, oxidation stability, and soot accumulation. These oils are specially effective in engines designed to meet 1994 exhaust emission standards and may also be used in engines requiring API Service Categories CD, CE, and CF-4. Oils designed for this service have been in existence since 1994. |
| CF-2 | Obsolete | Service typical of two-stroke cycle diesel engines requiring highly effective control over cylinder and ring-face scuffing and deposits. Oils designed for this service have been in existence since 1994 and may be used when API Service Category CD-II is recommended. These oils do not necessarily meet the requirements of API CF or CF-4 unless they pass the test requirements for these categories. |
| CF | Obsolete | Service typical of indirect-injection diesel engines and other diesel engines that use a broad range of fuel types, including those using fuel with high sulfur content; for example, over 0.5% wt. Effective control of piston deposits, wear and copper-containing bearing corrosion is essential for these engines, which may be naturally aspirated, turbocharged or supercharged. Oils designated for this service have been in existence since 1994 and may be used when API Service Category CD is recommended. |
| CF-4 | Obsolete | Service typical of high speed, four-stroke cycle diesel engines. API CF-4 oils exceed the requirements for the API CE category, providing improved control of oil consumption and piston deposits. These oils should be used in place of API CE oils. They are particularly suited for on-highway, heavy-duty truck applications. When combined with the appropriate S category, they can also be used in gasoline and diesel powered personal vehicles i.e., passenger cars, light trucks and vans when recommended by the vehicle or engine manufacturer. |
| CE | Obsolete | Service typical of certain turbocharged or supercharged heavy-duty diesel engines, manufactured since 1983 and operated under both low speed, high load and high speed, high load conditions. Oils designed for this service may also be used when API Service Category CD is recommended. |
| CD-II | Obsolete | Service typical of two-stroke cycle diesel engines requiring highly effective control of wear and deposits. Oils designed for this service also meet all performance requirements of API Service Category CD. |
| CD | Obsolete | Service typical of certain naturally aspirated, turbocharged or supercharged diesel engines where highly effective control of wear and deposits is vital, or when using fuels with a wide quality range (including high-sulfur fuels). Oils designed for this service were introduced in 1955 and provide protection from high temperature deposits and bearing corrosion in these diesel engines. |
| CC | Obsolete | Service typical of certain naturally aspirated, turbocharged or supercharged diesel engines operated in moderate to severe-duty service, and certain heavy-duty gasoline engines. Oils designed for this service provide protection from bearing corrosion, rust, corrosion and from high to low temperature deposits in gasoline engines. They were introduced in 1961. |
| CB | Obsolete | Service typical of diesel engines operated in mild to moderate duty, but with lower quality fuels, which necessitate more protection from wear and deposits; occasionally has included gasoline engines in mild service. Oils designed for this service were introduced in 1949. They provide necessary protection from bearing corrosion and from high temperature deposits in naturally aspirated diesel engines with higher sulfur fuels. |
| CA | Obsolete | Service typical of diesel engines operated in mild to moderate duty with high quality fuels; occasionally has included gasoline engines in mild service. Oils designed for this service provide protection from bearing corrosion and ring-belt deposits in some naturally aspirated diesel engines when using fuels of such quality that they impose no unusual requirements for wear and deposits protection. They were widely used in the 1940s and 1950s but should not be used in any engine unless specifically recommended by the equipment manufacturer. |
You can download these charts in PDF format from API's website.
| Spec | Status | Description |
|---|---|---|
| GL-1 | Active | The designation API GL-1 denotes lubricants intended for manual transmissions operating under such mild conditions that straight petroleum or refined petroleum oil may be used satisfactorily. Oxidation and rust inhibitors, defoamers, and pour depressants may be added to improve the characteristics of these lubricants. Friction modifiers and extreme pressure additives shall not be used. |
| GL-2 | Inactive | The designation API GL-2 denotes lubricants intended for automotive worm-gear axles operating under such conditions of load, temperature, and sliding velocities that lubricants satisfactory for API GL-1 service will not suffice. |
| GL-3 | Inactive | The designation API GL-3 denotes lubricants intended for manual transmissions operating under moderate to severe conditions and spiral-bevel axles operating under mild to moderate conditions of speed and load. These service conditions require a lubricant having load-carrying capacities exceeding those satisfying API GL-1 service but below the requirements of lubricants satisfying API GL-4 service. |
| GL-4 | Active | The designation API GL-4 denotes lubricants intended for axles with spiral bevel gears operating under moderate to severe conditions of speed and load or axles with hypoid (see note)gears operating under moderate speeds and loads. These oils may be used in selected manual transmission and transaxle applications where MT-1 lubricants are unsuitable. The manufacturer's specific lubricant quality recommendations should be followed. |
| GL-5 | Active | The designation API GL-5 denotes lubricants intended for gears, particularly hypoid (see note) gears, in axles operating under various combinations of high-speed/shock load and low-speed/high-torque conditions. |
| GL-6 | Inactive | The designation API GL-6 denotes lubricants intended for gears designed with a very high pinion offset. Such designs typically require protection from gear scoring in excess of that provided by API GL-5 gear oils. |
| MT-1 | Active | The designation API MT-1 denotes lubricants intended for non-synchronized manual transmissions used in buses and heavy-duty trucks. Lubricants meeting the requirements of API MT-1 service provide protection against the combination of thermal degradation, component wear, and oil-seal deterioration, which is not provided by lubricants in current use meeting only the requirements of API GL-1, 4, or 5. |
You can download API's Publication 1560 on gear oils for more detailed information.
| Spec | Status | Description |
|---|---|---|
| TA | Obsolete | Proposed classification for two-stroke engine oils required for extremely-small engines, typically less than 50 cc. Engine Tests for this classification were under preparation when the Coordinating European Council (CEC) withdrew support for this category. |
| TB | Obsolete | Proposed classification for two-stroke engine oils required for the engines of motor-scooters and other highly-loaded small engines, typically between 50 and 200 cc. The test sponsor no longer requires this category, and the classification has been abandoned. |
| TC | Current | Designed for various high-performance engines, typically between 200 and 500 cc, such as those on motorcycles and snowmobiles, and chain saws with high fuel-oil ratios - but not outboards. Two-cycle engine oils designed for API Classification TC address ring-sticking, pre-ignition and cylinder scuffing problems. |
| TD | Obsolete | Designed for water-cooled outboard engines, this classification used the identical engine test to that in the National Marine Manufacturers association (NMMA) TC-W category. API TD has been superseded, and is no longer accepted by the NMMA, who now recommend oils meeting the requirements of TC-W3 for water-cooled outboard engines. |
