Cummins ISX Engines — 15L Heavy-Duty Diesel

The ISX is a dual-overhead-cam, 15-liter inline-six built for long-haul duty cycles. It is the engine of choice in countless Kenworth, Peterbilt, Freightliner, International and Western Star sleeper and day-cab tractors, and it also appears in heavy vocational trucks. Power ratings commonly run from 400 to 600 HP, making it suitable for everything from regional LTL to heavy over-the-road and oversize hauling.

Because so many ISX-powered trucks were built, the used and remanufactured core supply is deep — which keeps replacement pricing reasonable and lead times short. That availability is a big reason fleets continue to rebuild and repower ISX trucks rather than replace the whole vehicle.

A low-mileage used ISX is the quickest path back to service and the lowest cost. A rebuilt ISX has worn components replaced, while a remanufactured ISX is restored to OEM specification with new bearings, liners, seals and reconditioned heads and crankshaft. For a truck you intend to run hard for several more years, a remanufactured ISX delivers the best long-term value and the strongest warranty.

We offer both long blocks and complete engines. With a long block you reuse your turbo, fuel system, EGR components and accessories; a complete engine arrives mostly dressed to cut shop time. We will spell out exactly what is included and your core requirements before you buy.

The ISX is a durable engine, but like any high-mileage big-bore diesel it has known wear areas — including EGR coolers and valves, turbo actuators, injectors and the overhead. A remanufactured or freshly rebuilt unit addresses these areas, and a dyno-tested used engine reduces the risk of an unknown. We will discuss the condition and history of any unit we quote so you can buy with confidence.