The American Petroleum Institute has approved its new Proposed Category 12 (PC-12) specification for heavy-duty engine oils. The standard has now been added to API 1509, the document that governs its Engine Oil Licensing and Certification System (EOLCS), clearing the way for products to be developed and certified under the new category, the API said in a press release.
API’s licensing is central to the North American lubricants market and holds sway over much of North and South America and other markets around the world. It sets performance standards and allows oil marketers to display certification marks, such as the well-known “Donut” symbol, once products meet strict testing requirements. While the system is voluntary, it is widely adopted by engine manufacturers and lubricant suppliers, making API approval a key step for market acceptance and credibility.
With PC-12 now approved, two new service categories – API CL-4 and API FB-4 – are officially available. These designations will appear on certified products and signal that the oils meet the latest performance standards. Although licensing does not begin until Jan. 1, 2027, companies can already start preparing formulations and packaging.
“Technically, the base specification should not propose any major challenges to formulators, and I expect conventional SAE 10W-30 and 15W-40 products to be available for first allowable use. Top-tier product and low-viscosity FB-4 products may take a little longer,” Steve Haffner, president of SGH Consulting, told Lube Report. “Even though the specification allows it, plans for commercial application of SAE XW-20 have not been announced. It will likely be years before significant heavy duty volumes exist for these grades.”
“There is a wild card due to the Iran war, with the potential need to spend effort to approve new formulations with alternative base stocks. This is a top-tier issue for both PCMO and HDDO, especially those that rely on Group III+ and Group III/III+ overall. SAE 0W-20 with the dexos1 credential is especially problematic,” Haffner said.
API says the early release of the new categories is intended to give the industry time to adapt. Oil producers can begin aligning their products with the new requirements, helping to avoid disruptions when the specification becomes fully active alongside the 2027 model year for heavy-duty engines.
The API licensee portal will open on June 1, 2026, allowing companies to register products in advance. This step is designed to streamline the approval process and ensure that certified oils are ready for market as soon as licensing officially begins, API said.
PC-12 introduces updated performance requirements aimed at modern heavy-duty engines. These include better resistance to oxidation, stronger protection against wear, improved compatibility with seals and elastomers, and safeguards for emissions control systems. The specification also supports lower-viscosity oils, which can help improve fuel efficiency while maintaining durability.