Spotlight

Understanding the PC-12 Category Upgrade

Heavy duty diesel engine oils will be undergoing a category upgrade in the coming years. The Proposed Category 12 (PC-12) engine oils are in development now and will be licensed for use in early 2027. We are here to help you navigate the change and provide perspective about the important pieces of information you should be aware of with this category upgrade and what this means for your engine.

What is PC-12?

In December 2022 the US Environmental Protection Agency (EPA) released a new rule that requires engine manufacturers to meet more stringent emissions standards. These regulations will come into effect in Model Year 2027 engines. While it is still three years away, engine manufacturers are working hard on technology to meet the new standards. The new standards are another step change in reducing emissions from heavy duty diesel engines, and include a 75% reduction on Nitrous Oxide (NOx) emissions, and a 50% reduction in Particulate Matter (PM).

All of these changes will mean that the heavy duty diesel engine oil will also need to change to help keep engines operating as their manufacturers intended. To that end, engine manufacturers made a request for a new engine oil category to facilitate the changes needed to meet the new regulations. This is called Proposed Category 12 (PC-12). PC-12 was formally endorsed by the American Petroleum Institute (API) in early 2022, and in the future, this will become the most modern oil standard. Right now, the new category is being called PC-12 (or proposed category 12), to be split into two parts PC-12a and PC-12b.