Cummins PX6

PACCAR launched the PX6 alongside the PX-8 in 2010 for the Kenworth T270 (Class 6) and T370 (Class 7). It was replaced by the PX-7 before the 2013 model year to meet EPA on-board-diagnostics requirements then coming into force — meaning the PX6 stayed in the lineup for only around three years.

The PX6 powered light- to medium-duty distribution and municipal trucks from Kenworth, where maneuverability and a strong power-to-weight ratio mattered most.

The PX6 too meets the strict North American NOx limit in force from the 2010 model year only through a combination of cooled exhaust-gas recirculation, a diesel particulate filter and an SCR catalyst with AdBlue dosing; injection is handled by a high-pressure common-rail system. Like the related Cummins ISB platform, the inline six runs on wet cylinder liners that can be replaced individually during a major overhaul rather than swapping the whole block. A turbocharged engine of this class also runs charge-air cooling as standard, cooling the compressed intake air before combustion to reduce thermal loading.

Because of its short production run, used PX6 units are now uncommon; buyers should check parts availability before purchase, since the successor PX-7 has itself moved through several further engine generations and older PX6-specific parts are not consistently stocked in the aftermarket.