Cummins PX8

The PX-6/PX-8 pairing grew out of the long-standing collaboration between Cummins and Paccar, in which established Cummins mid-range engines were given their own Paccar nameplate; the sources reviewed give no exact production dates or introduction year.

The PX-8 serves Class 6 and 7 medium-duty trucks, including Kenworth and Peterbilt chassis; ratings on record include PX8 260, 270, 300, 330 and 380.

The PX-8 too meets the strict North American NOx limits in force since 2010 only through EGR, a diesel particulate filter and an SCR catalyst with AdBlue dosing; injection is handled by a high-pressure common-rail system rather than the mechanical pump of earlier 6CTA generations. Like the related ISC platform, the engine runs on wet cylinder liners that can be renewed individually during a major overhaul. Its comparatively moderate specific output is typical of Class 6/7 vocational engines designed for pulling power and longevity rather than peak output.

Because the PX-8 is closely related to the Cummins ISC, that engine's known service points apply: regular oil and fuel filter changes, and — on EGR-equipped versions — inspection of the diesel oxidation catalyst (DOC); no weak points specific to the Paccar-badged variant are documented in the sources reviewed.