API Service Categories vs. ILSAC Standards
Comparing 2 standards across 12 specifications. 12 key differences identified.
The American Petroleum Institute (API) Service Categories define the chemical additive performance, oxidation resistance, sludge prevention, and wear protection of engine oils. Governing gasoline passenger engines with 'S' Service codes (API SP, SN PLUS, SN) engineered to prevent Low-Speed Pre-Ignition (LSPI), and commercial diesel engines with 'C' Commercial codes (API CK-4, FA-4).
ILSAC GF-6 (developed by the International Lubricant Standardization and Approval Committee of Japanese and American automakers) defines fuel economy, timing chain wear reduction, and engine durability standards. Splitting into GF-6A (backward-compatible for 0W-20, 5W-20, 5W-30, 10W-30) and GF-6B (dedicated to ultra-low viscosity 0W-16 oils).
Specification Comparison Table
12 Parameters| Parameter / Spec | ||
|---|---|---|
|
Standardization
|
API 1509 / ASTM D4485 / SAE J183 | ILSAC GF-6A / ILSAC GF-6B (Mandated May 2020) |
|
API SP Standard (Gasoline, 2020+)
|
Current top-tier gasoline standard: mandatory protection against Low-Speed Pre-Ignition (LSPI) and timing chain wear | — |
|
API SN PLUS (Gasoline, 2018)
|
Interim standard introducing turbocharged direct-injection (TGDI) LSPI mitigation additives | — |
|
API SN (Gasoline, 2010)
|
Standard high-temperature piston deposit protection and turbocharger sludge control (backward compatible to SM, SL) | — |
|
API CK-4 (Heavy-Duty Diesel, 2016+)
|
High-shear diesel oil designed for 2017+ on-highway heavy trucks with DPF and SCR exhaust aftertreatment (backward compatible) | — |
|
API FA-4 (Fuel Economy Diesel)
|
Lower HTHS diesel oil (2.9-3.2 cP) for fuel economy in modern commercial fleets (NOT backward compatible with older diesels) | — |
|
The API Donut Symbol
|
Licensed trademark on oil bottles verifying viscosity, API service level, and Resource Conserving status | — |
|
ILSAC GF-6A (Starburst Symbol)
|
— | Backward compatible with older GF-5 and GF-4 specifications for SAE 0W-20, 5W-20, 0W-30, 5W-30, 10W-30 |
|
ILSAC GF-6B (Shield Symbol)
|
— | Exclusively for SAE 0W-16 viscosity oils (NOT backward compatible with engines requiring GF-6A / GF-5) |
|
Timing Chain Wear Test (Sequence X)
|
— | A mandatory ASTM test that limits acceptable timing chain elongation over an extended multi-day cyclic engine run (specific pass/fail thresholds are set by the ASTM Sequence X test procedure, not reproduced here in full) |
|
Piston Deposit & Cleanliness (Sequence IIIH)
|
— | A high-temperature ASTM oxidation/deposit test that runs the oil under sustained elevated temperature to evaluate resistance to ring sticking and varnish formation (exact duration/temperature are set by the ASTM Sequence IIIH test procedure) |
|
Automaker Backing
|
— | Alliance of Automobile Manufacturers (Ford, GM, Stellantis) and Japan Automobile Manufacturers Association (Toyota, Honda, Nissan) |