January 2027 may seem like a long way off, but in the world of lubricant product development, there is much work to be done to prepare for the launch of two new heavy-duty oil categories. That is when the efforts of engine manufacturers, oil producers, additive suppliers and testing labs will all come together to deliver the next generation of lubricants.

To recap quickly, the PC-12 initiative was launched in the wake of the EPA and California Air Resource Board (CARB) announcements of stricter emission limits and equipment life standards set to take effect with the 2027 heavy duty model year. Specifically, that means a 90% reduction in nitrogen oxide (NOx) from what is currently allowed, and an extended useful life compliance requirement for emission control systems from around 400,000 to 650,000 miles. To meet these requirements, heavy-duty engine and truck OEMs are making further refinements to their engine and aftertreatment technology. They formally asked the oil industry to develop new oil categories suited to the needs of newer, more complex hardware components, and the American Petroleum Institute (API) gave the go-ahead.

PC-12, the “proposed category,” will actually be two categories. The industry is calling them CL-4 and FB-4, although those names have not been finalized. CL-4 will replace the current CK-4 standard, and FB-4 will supersede FA-4. CL-4 oils must be backwards compatible for mixed-age fleets, while FB-4 will accelerate development of thinner viscosity oils formulated for newer engines to support greater fuel economy. In both cases, new oils produced according to PC-12 specs must be able to support the higher operating temperatures and tighter tolerances associated with advanced engine design. Among the requirements for PC-12 oils are improved oxidation and wear protection for better engine durability and thermal stability. 

Improving Aftertreatment Performance and Service Life

Aftertreatment systems play an increasingly important role in meeting the 2027 emission targets. To help improve ATS performance and extend service life, the Engine Manufacturers Association (EMA) specifically asked for the new oil specifications to address “aftertreatment protection” and “optimized soot dispersancy.” Soot and ash buildup in aftertreatment systems can impair emission control performance and, in the worst cases, shorten equipment life. Accordingly, PC-12 specs call for a tighter “chemical box” with lower phosphorous and sulfated ash levels in C and F category oils. Chevron has a head start in this area with Delo^® 600 ADF, the first ultra-low-ash, heavy-duty lubricant, as it already meets the PC-12 chemical box requirements with its 60% less sulfur ash content than the current industry maximum allowance.

What’s Next?

Over the last half of 2024, the PC-12 testing requirements were finalized. In mid-2025, we are now in the product qualification and technical demo phase, with formal testing of oils well underway to establish the viability of PC-12 specs. Chevron and the other major heavy-duty lubricant producers are actively testing and trialing new PC-12-based formulations, and by the end of the year, final pass/fail limits will be established. The new year, 2026, will bring a mandatory waiting period to allow all suppliers to complete testing and get products ready for market. The first license date is January 1, 2027, and you should expect PC-12 products to start appearing in commercial channels that month.

Many heavy-duty fleet operators are already planning and budgeting for their 2027 new model acquisitions. That means it’s not too early to start planning for the transition to the new oil categories. Whether you are looking at a long-term upgrade or extending the life cycle of existing equipment, or both, Chevron is here to help you make informed decisions.