Short answer
API SP is a service category for gasoline engine oils, licensed by the American Petroleum Institute starting May 1, 2020, at the same time as ILSAC GF-6. It added engine tests aimed at low-speed pre-ignition (LSPI) and timing chain wear, two problems seen in small turbocharged, direct-injection engines. API SQ followed in March 2025, so check which category your owner’s manual names.
Where API SP came from
API’s gasoline categories start with S and advance a letter each time automakers and the oil industry agree that engine designs have moved far enough to need new tests. SP succeeded API SN and its 2018 SN Plus supplement, and it was developed in step with the automaker-led ILSAC GF-6 standard so the two could launch together.
Licensing runs through API’s Engine Oil Licensing and Certification System (EOLCS). An oil marketer submits test data, signs a license, and can then print the API service symbol (the “donut”) with SP in its top half.
What the SP engine tests target
The headline additions were the Sequence IX test for low-speed pre-ignition, an abnormal combustion event that can crack pistons in turbocharged direct-injection engines, and the Sequence X test for timing chain wear, run in a modern turbocharged engine. Neither problem was common when SN was written.
SP also carries updated versions of the long-running sequence tests for high-temperature oxidation and piston deposits (Sequence IIIH), low-temperature sludge (Sequence VH) and valvetrain wear (Sequence IVB), along with bench tests for volatility, foaming and seal compatibility.
API SP versus SP with Resource Conserving
The bottom half of the donut can read “Resource Conserving.” That version adds fuel economy, emission-system protection and turbocharger deposit requirements, and API defines SP with Resource Conserving as matching ILSAC GF-6A. It applies only to the low-viscosity grades covered by ILSAC, such as 0W-20, 5W-20, 5W-30 and 10W-30.
Plain API SP, without Resource Conserving, can be claimed by oils in other grades such as 0W-40, 5W-40, 10W-40 or 20W-50. Those oils pass the SP engine tests but are not judged against the ILSAC fuel economy limits.
How to use SP when choosing oil
Start with the owner’s manual: it gives the SAE viscosity grade and the category or automaker specification the engine was validated on. API’s general guidance is that each new gasoline category includes the performance of earlier ones, so a manual that lists SN or SM is normally satisfied by a correctly graded SP or SQ oil.
Automaker specifications such as GM dexos1 or European approvals are separate from API categories. If your manual lists one, look for that specification by name rather than relying on the API donut alone.
Frequently asked questions
Is API SP still current?
API SQ, licensed from March 31, 2025, is the newer gasoline category. Whether a given bottle shows SP or SQ depends on when and how it was licensed, and API’s online EOLCS directory lists which products currently hold which license.
Can I use API SP oil in an older car?
API states that its latest gasoline categories include the performance of earlier ones, so SP is generally acceptable where SN, SM or older is called for. Match the viscosity grade in the manual, and note that owners of flat-tappet classic engines often weigh zinc and phosphorus levels separately.
General maintenance information. Always follow your vehicle or equipment manufacturer’s requirements and the current product data. Questions? Email [email protected].