A new heavy-duty engine oil specification designed to support next-generation diesel engines is nearing completion and expected to be licensed beginning Jan. 1, 2027, according to experts speaking during a Shell press conference at the Technology & Maintenance Council Annual Meeting & Transportation Technology Exhibition.

The upcoming PC-12 oil category will introduce improved performance standards for heavy-duty engine oils, including better oxidation control, enhanced wear protection, and additional material compatibility requirements, panelists said.

The panel included: Karin Haumann, OEM technical services manager with Shell Lubricants; Bill O’Ryan, director of the engine oil licensing and certification system at the American Petroleum Institute (API); and Heather DeBaun, vehicle fluids technical specialist with Traton R&D.

O’Ryan explained that the development of a new engine oil category begins when engine manufacturers determine existing standards no longer meet evolving technical requirements. Such was the case with the introduction of lower-NOx-producing EPA27 engines, required to meet EPA emissions standards beginning in 2027.

The request is typically submitted through the Engine Manufacturers Association, triggering a multi-stage evaluation process coordinated through API and industry committees. If the need for a new category is confirmed, a New Category Development Team is formed to establish performance targets and testing protocols.

“This is a consensus-based process involving OEMs, oil marketers, additive companies and testing labs,” O’Ryan said.

Haumann, who leads the development team for PC-12, said the group has spent several years balancing competing performance requirements while ensuring test procedures and engine hardware will remain available for decades.

“We have to determine what the performance limits and targets should be and make sure they meet the needs expressed by the engine manufacturers,” she explained.

The new category is expected to remain viable through about 2040, requiring the development of new test methods to replace engines and components that may become obsolete.

Despite potential regulatory shifts, panelists emphasized that the development of PC-12 is driven primarily by engineering requirements rather than government mandates.

“The development of PC-12 is a technical exercise,” Haumann said. “We’re improving the oil standard so engine manufacturers and customers get better performance.”

DeBaun said the category will remain relevant regardless of regulatory changes because it addresses fundamental needs of modern engines. EPA27 is still under review, but the 0.035 g/hp/hr NOx limits are not expected to be modified between now and January.

“It will offer improvements we’re looking for in durability, oxidation control and wear protection,” she said.

Oil companies are already validating formulations through extensive testing. Haumann said Shell has accumulated about 8 million miles of on-road testing and more than 12,000 hours of off-highway testing while preparing products that will meet the new standard.

The oils are also being tested in both modern engines and older equipment to confirm performance and backwards-compatibility across a wide range of applications.

During the discussion, trucknews.com asked if FB-4 oils — the successor to today’s FA-4 specification — would be widely available when 2027 engines begin entering the market.

O’Ryan said the oils should be available once licensing begins but warned fleets may not see them immediately on Jan. 1.

“It will be available, but you’re not necessarily going to see it in the market on January 1, 2027,” he said, noting there will likely be a transition period as the industry shifts from CK-4 to CL-4 and from FA-4 to FB-4 formulations.

The pace of availability will largely be driven by market demand and the rollout of new engines designed to use the oils, panelists said.

Haumann added that while the new category introduces the potential for ultra-low-viscosity oils — including 0W formulations — their adoption will depend on engine design and fleet preferences.

“Those lower viscosities will largely be tied to future engines designed to use them,” she said. “It’s not something fleets will be required to adopt immediately.”

O’Ryan added fleets should look for the API service symbol, often called the “donut,” on packaging to verify the oil meets the new standard. API also maintains an online directory of licensed products and conducts global aftermarket audits to ensure oils bearing the certification meet required specifications.

Panelists said fleets should begin reviewing their current lubricant specifications and consult with engine manufacturers to determine which products will be recommended once PC-12 oils become available.