API has initiated development of a new category in response to the Engine Manufacturers Association (EMA)
Designed to coincide with implementation of new EPA and CARB HD on-highway regulations, the new category of diesel engine oil will include the following improvements:
- Increased oxidation performance
- New wear test capability
- Addition of lower viscosities
- Improved aftertreatment capability
- Expansion of elastomer compatibility
Engine test obsolescence will also be considered although it's unlikely that the T-11 and T-12 tests will be available for the new category. If needed, the New Category Development Team (NCDT) will develop a T-11 replacement.
First licensing of the oil products under the standard is expected no later than January 1, 2027.
Potential benefits to diesel engines include:
- Enabling new engine technologies that are expected to experience higher brake mean effective pressure (BMEP) and customer demands, as well as accommodating anticipated regulatory requirements of extended useful life and warranty periods.
- Supporting requirements for fuel economy for certain engine models.
- Supporting new elastomers used in modern engines.
There are potential environmental benefits to the new category and the possibility of longer oil drain intervals.