"API SP" and "API SN" are printed on almost every bottle of petrol engine oil sold in the UAE and the Middle East — but few drivers or workshop owners know what they really mean. This guide explains the API service categories, the real differences between API SP and API SN, where the newest API SQ fits in, and how to choose the right engine oil for your car.
What does the API rating on engine oil mean?
The American Petroleum Institute (API) defines performance categories for engine oils. Each category sets minimum results the oil must achieve in standardised engine and laboratory tests — for wear, deposits, sludge, oxidation and more.
- Categories beginning with "S" (Service) are for petrol (gasoline) engines — for example SL, SN, SP, SQ.
- Categories beginning with "C" (Commercial) are for diesel engines — for example CF, CI-4, CK-4. See our diesel oil guide.
The second letter moves forward through the alphabet as standards are updated, so a later letter means a newer, more demanding standard. Some oils carry both, such as API SN/CF, meaning they meet a petrol and a diesel category.
The API rating is different from the SAE viscosity grade (such as 5W-30 or 20W-50), which describes how thick the oil is at cold and hot temperatures. You need to choose both correctly.
API SL, SM, SN, SP and SQ — the timeline
| Category | Introduced | Designed for |
|---|---|---|
| API SL | 2001 | Petrol engines of 2004 and older models |
| API SM | 2004 | Petrol engines of 2010 and older models |
| API SN | 2010 | Petrol engines of 2020 and older models; improved deposit and sludge control and emission-system protection |
| API SN Plus | 2018 | Supplement to SN adding protection against low-speed pre-ignition (LSPI) |
| API SP | 2020 | Modern turbocharged and direct-injection (GDI) engines |
| API SQ | 2025 | Latest petrol engines; introduced together with ILSAC GF-7 |
Each new "S" category is designed to be backward compatible: an oil meeting a newer category can normally be used where an older one is recommended, as long as the SAE viscosity grade is also correct.
API SP vs API SN: the key differences
API SP was introduced in 2020 because car engines had changed. Small, turbocharged, direct-injection petrol engines run at higher pressures and temperatures, and API SN oils were not designed for some of the problems these engines create. Compared with API SN, API SP oils provide:
- Protection against low-speed pre-ignition (LSPI). LSPI is an abnormal combustion event in turbo GDI engines at low speed and high load. It can damage pistons and connecting rods. API SN does not include an LSPI test; API SP does.
- Timing chain wear protection. API SP adds a test for timing chain wear, a known issue in some modern engines.
- Better high-temperature deposit control on pistons and turbochargers.
- Improved sludge and varnish control for longer engine cleanliness.
| Feature | API SN | API SP |
|---|---|---|
| Year introduced | 2010 | 2020 |
| LSPI protection | Not tested (added only in SN Plus) | Required |
| Timing chain wear test | No | Yes |
| Turbocharger & piston deposits | Good | Improved |
| Best suited to | Older and naturally aspirated petrol engines | Modern turbo and GDI engines, and all older engines |
| Backward compatible | Replaces SM, SL and older | Replaces SN Plus, SN, SM, SL and older |
Where does API SQ fit in?
API SQ is the newest petrol engine oil category, introduced in 2025 together with the ILSAC GF-7 standard. It builds on API SP with further improvements in deposit and sludge control, wear protection and fuel economy for the latest engines. As new car models arrive in the Middle East specifying GF-7 or API SQ, demand for these oils will grow. NITSOIL has recently introduced an API SQ engine oil — contact our team for details.
Which one should you use?
- Always start with the owner's manual. Use the viscosity grade and minimum API category the car maker recommends.
- Modern turbo or direct-injection cars (most cars from about 2015 onwards): choose API SP or SQ.
- Older or naturally aspirated cars: API SN is suitable where the manual specifies SN or older — but API SP or SQ can also be used and gives extra protection.
- Hot climates such as the UAE: high ambient temperatures, long idling in traffic and stop-start driving put extra stress on oil. A quality oil at the correct grade and on-time oil changes matter more than ever.
NITSOIL petrol engine oils
API SP: 0W-16, 0W-30, 0W-40, 5W-20
API SN: 0W-20, 5W-30, 5W-40 SN/CF, 10W-30, 10W-40 SN/CF, 20W-50, 20W-60
API SL/CF: 10W-30, 10W-40, 15W-40, 25W-60
Frequently asked questions
Can I use API SP oil in an older car that needs API SN?
Yes. API SP is backward compatible with API SN and earlier categories. Make sure the SAE viscosity grade (for example 5W-30) matches what the manual recommends.
Can I use API SN oil in a new car that needs API SP?
It is not recommended. API SN oil has not been tested for LSPI or timing chain wear, which are important for modern turbocharged direct-injection engines. Use the category the manufacturer specifies or newer.
Is API SP better than API SN?
API SP is a newer, more demanding standard with additional protection for modern engines. For an older engine designed for SN, both will work well if the viscosity grade is correct.
What does API SN/CF mean?
The oil meets API SN for petrol engines and API CF for diesel engines, so it can be used in mixed fleets with older light diesel engines, where the manufacturer allows it.
Talk to a UAE lubricant manufacturer
Get product recommendations, TDS/SDS documents and pricing for your market from the NITSOIL team.