API
The current and previous API Service Categories are summarized in convenient charts. Vehicle owners should refer to their owner's manuals before consulting these charts. Oils may have more than one performance level. For automotive gasoline engines, the latest engine oil service category includes the performance properties of each earlier category. If an automotive owner's manual calls for an API SN oil, an API SP oil will provide full protection. For diesel engines, the latest category usually - but not always - includes the performance properties of an earlier category.
Gasoline Engines
The current and previous API Service Categories are listed here. Vehicle owners should refer to their owner’s manuals before consulting these charts. Oils may have more than one performance level.
| Category | Service |
| SP | Introduced in May 2020 |
| SN | For 2020 and older automotive engines |
| SM | For 2010 and older automotive engines. |
| SL | For 2004 and older automotive engines. |
| SJ | For 2001 and older automotive engines. |
| SG | For 1993 and older automotive engines |
| SF | For 1988 and older automotive engines |
| SE | For 1979 and older automotive engines |
| SD | For 1971 and older automotive engines |
| SC | For 1967 and older automotive engines |
For
automotive gasoline engines, the latest API Service Category includes
the performance properties of each earlier category and can be used to
service older engines where earlier category oils were recommended.
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.
Diesel Engines
Follow your vehicle manufacturer’s recommendations on oil performance levels
API
FA-4 and the FA-4 Donut identify 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. API FA-4 oils are not interchangeable or backward
compatible with API CK-4, CJ-4, 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.
| Category | Service |
| CK-4 | High-speed four-stroke cycle diesel engines designed to meet 2017 |
| CJ-4 | High-speed four-stroke cycle diesel engines designed to meet 2010 and with higher than 15 ppm sulfur fuel |
| CI-4 | Introduced in 2002. |
| CH-4 | 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. |
| CF-4 | Suitable for use in most diesel-powered automotive engines built before 2009. |
| CD | Suitable for use in most diesel-powered automotive engines built before 1994. |
| CC | For Diesel Engine designed before 1990. |