API Approves New PC-12 Heavy-Duty Engine Oil Specification for 2027

The American Petroleum Institute announced that the new API Proposed Category 12 (PC-12) heavy-duty engine oil specification has been formally approved and will be incorporated into API 1509, the Engine Oil Licensing and Certification System document, according to a press release.

With the announcement, the API Service Category CL-4 and API FB-4 “Donut” certification marks are now available. Oil marketers can begin finalizing formulations and preparing product packaging to meet the new specifications ahead of the first licensing date of Jan. 1, 2027.

To further support industry readiness, the API licensee portal will open on June 1, 2026. This early-access period will allow licensees to proactively enter new API CL-4 and API FB-4 products into the system.

The new engine oil specifications aim to improve oxidation resistance, enhance wear protection, expand elastomer compatibility, improve after treatment system protection, and provide support for lower viscosity grades aimed at improving fuel economy.

“To support the next generation of heavy-duty engine technology and emissions standards, PC-12 establishes a strong technical foundation for performance, durability and environmental protection,” said Bill O’Ryan, director-EOLCS/DEF with API. “Making the CL-4 and FB-4 service symbols available now allows oil marketers to prepare for a smooth transition as we approach the 2027 model year.”