New Diesel Engine Oil Blends Are Designed to Keep DPFs From Clogging So Darn Much

New heavy-duty diesel engine oil blends in the API PC-12 category aim to reduce soot buildup that can clog diesel particulate filters (DPFs). In a discussion with The Diesel Podcast, Chevron Lubricants principal engineer Shawn Whitacre said emissions-control systems have forced oil makers to lower additive levels—especially sulfated ash—to avoid plugging after-treatment equipment. PC-12 is intended to remain backward compatible for engines from 1998 onward and could help lessen the frequency of DPF regenerations. The American Petroleum Institute approved the PC-12 license earlier this year to support EPA 2027 heavy-duty engine rules. Those standards require large nitrogen-oxide reductions, driving redesigns across exhaust and after-treatment systems.