A Complete History of Engine Oil Classification: SAE, API, ACEA, ILSAC & JASO (Origins to 2026)

Engine oil classification did not begin as one global standard — it grew from five separate systems that still operate side by side today: SAE J300 (first issued in 1911) classifies oil by viscosity alone; API's "S" and "C" categories, together with ILSAC's GF specifications, define US gasoline- and diesel-engine performance levels; and ACEA (Europe) and JASO (Japan, including motorcycles) each define their own regional and application-specific sequences. This article — part of Altonex Global's Knowledge Hub — traces how each system originated and evolved, from SAE's first numerical grades through the API SQ and ILSAC GF-7 categories that began licensing in 2025, and shows exactly where every system stands heading into 2026.

What Is Engine Oil Classification, and Why Are There Five Different Systems?

Engine oil classification is the set of rules that let a label reading "5W-30" or a supplier data sheet marked "API SN, ACEA A3/B4" communicate exactly what an oil is capable of, without a buyer needing to test it directly. Because no single organization owns the entire question, five bodies each answer a different piece of it:

• SAE (Society of Automotive Engineers) — defines viscosity grades (how the oil flows at cold start and at operating temperature) under the J300 standard.
• API (American Petroleum Institute) — defines US performance categories: "S" (Service) for gasoline engines and "C" (Commercial) for diesel engines.
• ILSAC (International Lubricant Standardization and Approval Committee) — defines GF specifications for US/Japan passenger-car gasoline engines, layering fuel-economy and emissions-system-protection requirements on top of API's categories.
• ACEA (Association des Constructeurs Européens d'Automobiles) — defines European performance sequences: A/B for gasoline and light-duty diesel, C for low-emissions formulations, E for heavy-duty diesel.
• JASO (Japanese Automotive Standards Organization) — defines standards for requirements the other four do not cover, most notably motorcycle wet-clutch compatibility (T903), plus Japanese-market two-stroke oils (M345) and diesel oils (M355).

A single product can legitimately carry ratings from several of these systems at once — for example, a 5W-30 oil (SAE) meeting API SP and ACEA A3/B4 — because each system measures a different property, not a competing version of the same one.

What Came Before the Modern Classification Systems?

Before industry-wide cooperation produced today's alphabetic and numeric systems, engine oil specifications were fragmented across individual companies, national bodies and militaries. The most frequently cited example is the US military's lubricant specification lineage, which traces to World War II-era US Army ordnance documentation and was later formalized into the MIL-L-2104 series (subsequently redesignated MIL-PRF-2104). The exact date of that formalization is not firmly established in the sources reviewed for this article, though it is generally placed in the early-to-mid 1950s.

This fragmentation is part of what the 1970 cooperative arrangement between API, SAE and ASTM was designed to resolve for the US market — a tripartite (three-body) effort that established the alphabetic "S" and "C" system still in use today. A similar consolidation happened in Europe roughly two decades later, when CCMC's classifications (used from 1972) gave way to ACEA's unified sequences in 1996.

What Is the Complete Timeline of Engine Oil Classification Milestones?

The table below gathers the confirmed and well-corroborated milestones from all five systems into a single chronological view. Entries marked "circa" or "reported" are corroborated by more than one source but are not confirmed to the same standard as the dates stated plainly.

How Did SAE J300 Viscosity Grades Evolve From 1911 to Today?

SAE issued its first formal lubricant specification in 1911, "Specification No. 26." The system recognizable today began to take shape in 1926, when SAE established six numerical viscosity grades spanning SAE 10 to SAE 60; grade 70 was reportedly added in 1928, rounding out the high end of the range.

For decades, engine oils were single-grade only — a summer-weight oil and a separate winter-weight oil, changed seasonally. Winter "W" grades were established in the early-to-mid 1950s, though the exact year and the original grade line-up are not firmly documented in the historical record. Multigrade oils — a single formulation meeting both a winter and a summer grade, the format familiar today as "10W-30" or "5W-40" — emerged commercially in the United States in the early-to-mid 1950s, enabled by the development of Viscosity Index Improver (VII) additive chemistry, which allows an oil's viscosity to resist thinning as temperature rises. Several early formulations have been associated with this transition, but historical accounts disagree on which reached the market first, so no single product can be confirmed as the original commercial multigrade oil.

SAE reportedly formalized a standard multigrade labeling scheme around 1955, and the now-familiar "J300" document identifier is reported to have been attached to the standard around 1962. Since then, J300 has been revised repeatedly, tracking the industry's decades-long push toward thinner, more fuel-efficient formulations.

The Shift Toward Ultra-Low Viscosity Grades

That push accelerated in the 2010s. On 2 April 2013, J300 added viscosity grade "16," making the now-common 0W-16 grade possible. Less than two years later, in January 2015, SAE added grades "8" and "12," opening the door to 0W-8 and 0W-12 — oils thinner than almost anything on the market a decade earlier. A 2021 revision (J300_202104) added ASTM D7042 as a permitted test method for kinematic-viscosity-related measurements. The current edition, J300_202405, was published in May 2024 with a restructured grade table.

J300 also sets minimum high-temperature, high-shear (HTHS) viscosity floors for each grade — a property that protects bearings, cams and other high-load surfaces once an engine is running hot.

SAE maintains a related but separate standard for driveline lubricants — gear oils and transmission fluids — under document J306. That standard was renamed "Automotive Driveline Lubricant Viscosity Classification" in its February 2025 edition (J306_202502), which added a set of ultra-low winter grades, 62W through 65W, aimed at lubricants used in electric-vehicle drive units. J306 is a distinct classification from J300 and does not grade engine oil.

How Did API's "S" Gasoline-Engine Categories Develop From SA to SQ?

API's gasoline-engine ("Service," or "S") categories run alphabetically from SA through the current SP and SQ, with each letter historically representing a step up in performance, additive technology or emissions-system compatibility. According to API's published category list, most early letters have long since been declared obsolete for vehicles built after a specific model year:

SJ followed, reported around 1996. API SL was introduced in 2001, and API SM followed on 30 November 2004. API SN was introduced in October 2010 and was extended in 2017–2018 to address a specific failure mode: API approved "SN PLUS" on 9 November 2017, adding protection against low-speed pre-ignition (LSPI), with licensing beginning 1 May 2018.

The current top-tier gasoline categories are API SP, which began licensing 1 May 2020, and API SQ, which launched on 31 March 2025 alongside ILSAC's GF-7 specifications. SQ adds coverage for the newer, thinner 0W-8 and 0W-12 grades and sets a maximum sulfated-ash limit of 0.9%. Importantly, SQ does not supersede SP — both remain current, valid categories, and a supplier's product may legitimately carry either rating depending on its formulation. Our side-by-side comparison of API SP and API SQ walks through the practical differences in more detail.

Suppliers on Altonex Global who list petrol engine oils typically state the specific API "S" category — and, where relevant, the ILSAC Starburst or Shield designation — alongside the SAE viscosity grade on the product listing. Buyers can browse current petrol engine oil listings on Altonex Global and confirm the exact specification and any supporting documentation directly with the supplier.

How Did API's "C" Diesel-Engine Categories Develop From CA to FA-4?

API's diesel ("Commercial," or "C") categories follow a parallel alphabetic track. The earliest letters — CA, CB, CC and CD — were introduced across the 1950s to the early 1960s and are now long obsolete; the historical record reviewed does not support a precise introduction year for any of the four. CE followed, reported around 1985, and CF-4 followed, reported around 1990–1991.

From the mid-1990s, the record becomes considerably more precise, largely because each new category was tied to a specific US EPA heavy-duty emissions standard:

The most recent diesel categories, CK-4 and FA-4, launched simultaneously on 1 December 2016, the result of a multi-year industry development effort known as "PC-11." CK-4 is backward-compatible with earlier categories and spans the full range of diesel viscosity grades. FA-4 is a fuel-economy-oriented category restricted to XW-30 grades and is explicitly not backward-compatible — it cannot simply be substituted into an engine that was not designed to use it, so buyers and fleet operators need to confirm which of the two a given product is licensed under before ordering.

Both CK-4 and FA-4 remain the current top-tier API diesel categories as of 2026. Suppliers on Altonex Global who list heavy-duty diesel formulations typically specify which of the two — and which viscosity grade — a given product carries; buyers can review current diesel engine oil listings on Altonex Global and confirm category, grade and supporting test documentation with the supplier directly.

How Did ILSAC's GF Specifications Emerge and Evolve?

ILSAC — the International Lubricant Standardization and Approval Committee — was formed in 1992 by Ford, General Motors, Chrysler and Japan's JAMA (Japan Automobile Manufacturers Association) to define a passenger-car gasoline-engine specification that combines API's performance categories with additional fuel-economy and emissions-system-protection requirements, identified on-pack by the "Starburst" symbol. Its first specification, GF-1, followed — reported variously as 1990 or 1992, depending on the source.

Subsequent GF generations followed roughly every five years: GF-2 is reported around 1996, GF-3 around 2001, and GF-4 around 2004. ILSAC GF-5 was introduced in 2010.

The pace then became more tightly documented. ILSAC GF-6 split into two parallel categories — GF-6A and GF-6B — that began licensing on 1 May 2020 alongside API SP. GF-6B is restricted to the 0W-16 grade and, because it is not backward-compatible with older engines, is identified by a new logo introduced specifically for it: the "Shield" mark. On 1 May 2021, GF-6A became the exclusive basis for the Starburst mark, as GF-5 licensing formally ended the day before, on 30 April 2021.

The current generation, GF-7, began licensing on 31 March 2025 (its ballot passed on 22 March 2024), again split into two categories: GF-7A, covering the 0W-20, 5W-20, 0W-30, 5W-30 and 10W-30 grades, and GF-7B, restricted to 0W-16. GF-7 introduced a new Aged-Oil low-speed pre-ignition (LSPI) test and, matching API SQ, a maximum sulfated-ash limit of 0.9%. Our dedicated guide to API SQ and ILSAC GF-7 covers the licensing detail and grade coverage in full.

How Did CCMC Evolve Into ACEA, and What Do the A/B/C/E Sequences Mean?

Europe's classification system predates ACEA. CCMC — the Comité des Constructeurs du Marché Commun, a European vehicle-manufacturers' body — was founded in 1972 and issued its own engine-oil performance grades, including reported G-1/G-2 gasoline-engine grades around 1984 and G-4/G-5 grades in 1989.

ACEA — the Association des Constructeurs Européens d'Automobiles — was founded as CCMC's successor body, reported around 1991. ACEA's own sequences formally replaced the CCMC classifications on 1 January 1996, and ACEA has issued a new sequence roughly every one to four years since — including editions in 1998, 1999, 2002, 2004, 2007, 2008, 2010, 2012 and 2016 — each tightening emissions-system compatibility, oxidation stability or fuel-economy requirements for European-market engines.

What the A/B/C/E Letters Mean

ACEA organizes its sequences by letter: "A" and "B" cover gasoline and light-duty diesel passenger-car engines respectively (and are frequently combined, e.g., "A3/B4"), "C" covers low-emissions/low-SAPS formulations compatible with modern aftertreatment systems, and "E" covers heavy-duty diesel engines. The low-SAPS "C" categories — C1 through C4 — were introduced in the 2002 sequence and have expanded since: C5 is reported to have been added in the 2016 edition, and C6 reported added in 2022 (the 2022 edition is also reported to have withdrawn some earlier categories, though these specific sub-changes are less firmly documented than the E8/E11 replacement below). ACEA's 2023 light-duty sequences, mandatory for any new performance claim from 1 August 2024, added category C7 for 0W-16 formulations.

On the heavy-duty side, ACEA's E6 and E9 sequences were replaced by E8 and E11 in May 2022, and E6/E9 became fully obsolete in May 2024. ACEA published its most recent heavy-duty sequences edition in 2024. As of 2026, ACEA's current framework is the 2023 light-duty sequences alongside the 2024 heavy-duty sequences.

How Did JASO Build Separate Standards for Motorcycles and Diesel Engines?

JASO — the Japanese Automotive Standards Organization — maintains classification systems that address requirements none of the other four bodies cover directly, the most significant being motorcycle-specific wet-clutch compatibility.

JASO launched T903 in 1998, defining MA and MB grades. The standard exists because passenger-car engine oils formulated with friction-modifier additives (added to reduce fuel consumption) were causing wet-clutch slippage in motorcycles that share a single oil supply between the engine and a wet clutch or transmission — a problem that does not exist in cars, which use a separate transmission fluid. T903 was revised in 2006, subdividing the MA grade into MA1 and MA2; revised again in 2011; and revised again in 2016 to add a gear-pitting test. The current edition, T903:2023, took effect on 1 October 2023.

Two-Stroke and Diesel: JASO's Other Standards

JASO also maintains M345, a standard for two-stroke engine oils, launched in 1994 as M345-93 with grades FA, FB and FC; a 2004 revision dropped the FA grade and added FD.

For diesel engines, JASO's M355 standard was published in 2000, with its DH-1 grade reaching the market on 1 April 2001. M355 was revised in 2005 to add DH-2 and DL-1 grades, and again in 2021 to add DL-2. The current edition, M355:2024, took effect on 1 October 2024.

Where Does Each Classification System Stand in 2026?

As of 2026, all five systems are active in parallel, and — notably — very few older top-tier categories have been withdrawn outright; most remain valid even after a newer category launches alongside them.

• SAE: J300_202405 (May 2024) is the current viscosity-grade table, spanning ultra-low grades like 0W-8 through the traditional 60-weight range. The related driveline standard, J306_202502 (February 2025), is current for gear oils and transmission fluids, including new EV-drive winter grades.
• API (gasoline): SP and SQ are both current; SQ does not replace SP.
• API (diesel): CK-4 and FA-4, both launched December 2016, remain the current top-tier heavy-duty diesel categories.
• ILSAC: GF-6A/GF-6B and the newer GF-7A/GF-7B are all current; GF-6 licensing is being phased out, with a last-use date extended to 1 October 2026.
• ACEA: the 2023 light-duty sequences and the 2024 heavy-duty sequences are the current framework.
• JASO: T903:2023 (motorcycle, effective 1 October 2023) and M355:2024 (heavy-duty diesel, effective 1 October 2024) are current.

None of these five bodies is affiliated with Altonex Global, and Altonex Global does not test, license, certify or endorse any classification claim. Altonex Global is a trade-discovery and RFQ platform: suppliers who list petrol and diesel engine oils on the platform are responsible for the accuracy of the SAE, API, ILSAC, ACEA or JASO ratings they publish. A buyer who needs to confirm a specific license number, approval letter or test report can request it directly from the supplier through a Request for Quotation.

What Are the Key Takeaways From This History?

• Engine oil classification did not begin as one unified system — it grew from five separate bodies (SAE, API, ILSAC, ACEA, JASO) that each answer a different technical question, and a single product can carry ratings from several of them at once.
• SAE J300 has been repeatedly extended at the low-viscosity end — from the original numerical 10–60 range to modern ultra-low grades like 0W-8, 0W-12 and 0W-16 — tracking the industry's long shift toward thinner oils for fuel economy.
• The API alphabetic "S" (gasoline) and "C" (diesel) system, cooperatively established with SAE and ASTM in 1970, is still the naming framework used for every category from those early letters through today's SQ and FA-4.
• ACEA's European sequences descend from CCMC, a predecessor body reported active from 1972 through the mid-1990s; ACEA formally took over classification in 1996 and still issues updated sequences, most recently 2023 for light-duty and 2024 for heavy-duty engines.
• JASO's standards fill a gap the other four systems do not address — most notably motorcycle wet-clutch compatibility (T903) — reflecting requirements specific to Japanese and broader motorcycle and diesel markets.
• 2024–2025 was an unusually active period across the whole family of standards: API SQ, ILSAC GF-7A/GF-7B, a restructured SAE J300 table, and current ACEA and JASO editions are all in force at the same time, with most predecessor categories (such as API SP and ILSAC GF-6) remaining valid rather than being withdrawn outright.

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