The American Petroleum Institute (API) has taken a major step toward finalizing its next heavy‑duty engine oil standard, announcing that the API Lubricants Standards Group (LSG) has approved several foundational actions for the upcoming API Proposed Category 12 (PC‑12) specification.
The decisions move the industry closer to the first license date for the new API CL‑4 and API FB‑4 categories, set for January 1, 2027.
According to the announcement, the LSG approved three key items that will now advance to an electronic ballot for inclusion in API 1509:
- acceptance of the PC‑12 technical requirements as outlined in the ASTM D4485 ballot with minor editorial updates;
- acceptance of the PC‑12 user language describing the API CL‑4 and API FB‑4 categories;
- acceptance of the 2027 first license date.
These ballots will undergo a 30‑day review and voting period, giving API members an opportunity to provide final feedback before adoption.
The progress reflects months of coordinated technical work across the diesel engine oil sector. During recent ASTM D02 meetings, the Diesel Engine Oil Advisory Panel (DEOAP) and the PC‑12 New Category Development Team (NCDT) aligned on updates to the ASTM D4485 standard. Those recommendations were then forwarded to the API LSG, which confirmed the path forward for PC‑12 development.
As a recent prelease release note states, “These actions mark a significant milestone toward finalizing the PC‑12 specification and preparing the heavy-duty engine oil industry for next-generation performance standards.”
Why PC‑12 Matters
PC‑12 represents the next major evolution in heavy‑duty engine oil categories, following the introduction of API CK‑4 and FA‑4 in 2016.
The new specification is being developed to meet the needs of advanced diesel engines designed for tighter emissions regulations, improved fuel efficiency, and greater durability under severe operating conditions.
PC‑12 is expected to include two subcategories—CL‑4 and FB‑4—mirroring the split‑category approach used in CK‑4/FA‑4 to address both traditional and fuel‑efficient engine designs.
The development of PC‑12 is driven in part by upcoming US Environmental Protection Agency (EPA) and California Air Resources Board (CARB) emissions standards for heavy‑duty engines.
These regulations will require oils that can withstand higher operating temperatures, protect aftertreatment systems, and maintain performance over longer drain intervals.
For service truck operators, fleets, and maintenance professionals, the new categories will influence oil selection, warranty compliance, and long‑term engine protection strategies.
About the American Petroleum Institute
Founded in 1919, the American Petroleum Institute is the primary trade association representing the US oil and natural gas industry. API develops widely adopted technical standards, including the engine oil categories used across the automotive, trucking, and heavy‑equipment sectors.
The organization’s “donut” and “shield” certification marks are recognized globally as indicators of oil quality and performance.
API’s standards development process brings together engine manufacturers, oil companies, additive suppliers, and testing organizations to ensure that new categories meet both regulatory and real‑world performance needs.
Next Steps for Industry and Licensees
To support a smooth transition, API will open its licensee portal several months before the January 1, 2027, first license date.
This early‑access period will allow companies to enter new API CL‑4 and API FB‑4 products ahead of launch. API will notify licensees once early entry becomes available.
For service truck operators and maintenance teams, the rollout of PC‑12 will signal the start of a new generation of heavy‑duty lubricants engineered for cleaner, more efficient diesel engines.
As the industry moves toward 2027, fleets can expect increased communication from oil suppliers, OEMs, and distributors about how the new categories will affect product selection and service intervals.