The American Petroleum Institute (API) Lubricants Group has agreed to move forward with balloting on three proposals tied to the next heavy-duty engine oil category, API PC-12, a step that would allow first product licensing in the United States beginning Jan. 1, 2027.
The decision was taken during a Dec. 11 meeting in Houston, Texas, where the U.S.-based standards body approved a 30-day ballot period covering incorporation of PC-12 into API 1509, the Engine Oil Licensing and Certification System (EOLCS), along with associated user guidance and the proposed licensing timeline.
Should the ballot be approved in January 2026, lubricant marketers would be able to apply for licenses for API CL-4 and API FB-4, the official designations for PC-12A and PC-12B, starting in 2027.
API PC-12 is intended to replace the current API CK-4 and FA-4 categories and align engine oil performance with 2027 model-year heavy-duty engine requirements across the United States and the wider North American market. Under the framework, API CL-4 would serve as the backward-compatible option for mixed fleets and existing engine designs, while API FB-4 would address lower-viscosity, fuel-efficient oils formulated for engines engineered specifically to meet the new specification.
Although the ballot establishes a clear schedule, several technical matters remain unresolved. One key issue is the expected phaseout of the Sequence IV-A engine wear test, with industry estimates suggesting that available test hardware could be exhausted by the end of 2026. The test, which evaluates valvetrain wear protection including cam and tappet durability, remains a required component of the API CL-4 performance matrix.
Concerns also continue around the lack of demonstrated correlation between Sequence IV-A and its proposed replacement, Sequence IV-B, raising uncertainty over how backward-compatible wear protection will be validated for CL-4 oils under the API PC-12 structure.
To examine potential paths forward, the API Lubricants Group has asked Brent Calcut of Afton Chemical, who chairs the Classification Lubricants Oversight Group (CLOG), to lead a task force reviewing available options. These include assessing whether any existing bench tests could provide an acceptable correlation to IV-A performance.
Despite the outstanding technical challenges, API’s decision to advance the ballot reflects broad industry consensus that development of the API PC-12 heavy-duty engine oil category must stay aligned with regulatory expectations and original equipment manufacturer timelines. For now, industry participants continue to plan around a January 1, 2027 first-licensing date, while technical work proceeds through 2026.