Cummins X15
Used Cummins X15 Engine for Sale
The X15 replaced the ISX15 in Cummins heavy-duty lineup and is offered in Efficiency and Performance Series ratings. Send us your engine serial number (ESN) and CPL and we search supplier sources nationwide for a matching used X15.
Cummins X15 at a glance
- Displacement
- 14.9 L (about 912 cu in)
- Configuration
- Inline 6-cylinder, single overhead cam, XPI common-rail fuel system
- Typical horsepower range
- About 400 to 605 hp depending on series and rating
- Production era
- 2017 model year to present (on-highway)
- Emissions / aftertreatment
- GHG17 and later; cooled EGR, VGT turbo, DOC, DPF and SCR (DEF)
- Common applications
- Class 8 linehaul, regional haul and heavy vocational trucks
Identification
How to identify your X15
Read us the engine serial number (ESN) and the CPL (Control Parts List) number from the Cummins engine dataplate. On the X15 the dataplate is a label on the engine, commonly on the rocker (valve) cover; if it is missing or unreadable, the ESN can also be pulled from the ECM with diagnostic software, and it is stamped on the block.
The CPL tells a supplier which turbo, fuel system, aftertreatment calibration and accessory layout the engine was built with. Two X15 engines with different CPLs may not be drop-in swaps even when the horsepower is the same.
- ESN (8 digits) and CPL number from the dataplate
- Series: Efficiency or Performance, and the advertised horsepower/torque rating
- Truck year, make, model and VIN
- Transmission (manual, Eaton Endurant or other AMT) since some ratings are paired with specific drivetrains
01Efficiency Series vs Performance Series
Cummins sells the X15 in two main on-highway families. The Efficiency Series is aimed at linehaul fuel economy with lower horsepower ratings and is often spec'd with automated transmissions and fast-rear-axle ratios. The Performance Series carries the higher horsepower and torque ratings used for heavy haul, mountain routes and some vocational work.
The two series share the same 14.9 L base engine, but ratings, calibrations and some hardware differ. Tell us which series your truck has (it is on the dataplate rating and in the ECM) so the replacement is quoted against the same family. A Productivity Series was also offered for some applications; we confirm the exact rating from your ESN.
02What changed from the ISX15
The X15 is a development of the ISX15 rather than a clean-sheet design, but the two are not interchangeable as complete engines without work. The X15 runs a newer ECM platform and calibration, revised turbo and EGR hardware, and a single-module aftertreatment system on many trucks.
If your truck was built with an ISX15, quote an ISX15 unless you and your shop have planned the wiring, ECM, aftertreatment and chassis programming changes an X15 conversion requires.
03ECM, harness and aftertreatment compatibility
On an X15 the engine ECM, the aftertreatment sensors (NOx, temperature, pressure) and the truck's body and transmission controllers all talk to each other. A used X15 that comes with its ECM may still need to be reprogrammed to your VIN and truck options, and the aftertreatment system on your chassis needs to match what the engine calibration expects.
Ask whether the engine is offered with or without the ECM, engine harness and turbo. Those items change the quote and the amount of setup work at your shop.
04Freight and core considerations
A dressed X15 is a heavy, tall engine, and it typically ships on a pallet or engine stand by truck freight. Freight cost depends on your location, liftgate needs and whether it goes to a shop with a forklift. Core return terms, if any, are set per supplier and spelled out on your quote.
Before you buy
Questions to ask about a used X15
- Is the mileage documented by an ECM report or the donor truck's odometer and VIN?
- Is an oil analysis report available for this engine?
- Is there a running video showing cold start, idle and the engine under load if possible?
- Is it an Efficiency or Performance Series engine, and does the CPL match my truck?
- Does the engine come with the ECM, engine harness, VGT turbo and EGR components?
- Is any aftertreatment (DPF, SCR, DOC) included, or engine only?
- Was the engine pulled from a running truck, and why was it removed?
- Is a core required, and what condition does the core need to be in?
FAQ
Cummins X15 questions
Will any X15 fit my truck?
Not automatically. X15 engines vary by series, rating, CPL, ECM calibration and aftertreatment layout. We match by your ESN, CPL and truck VIN, and the supplier confirms fitment details on your quote.
Can I replace an ISX15 with an X15?
It can be done, but it is a conversion, not a bolt-in swap. ECM, wiring, aftertreatment and chassis programming all need to be addressed. Most owners are better served by quoting the same engine the truck was built with.
Where do I find the X15 CPL number?
The CPL is printed on the Cummins engine dataplate next to the ESN. If the label is damaged, a Cummins-capable shop can read the ESN from the ECM, and the build information can be looked up from it.
Is the Efficiency Series lower horsepower?
Generally yes. Efficiency Series ratings sit at the lower end of the X15 range for linehaul fuel economy, and Performance Series covers the higher ratings. Your exact rating comes from the dataplate or ECM.
Do used X15 engines come with the aftertreatment?
It depends on the supplier and the engine. Many used engines are offered engine-only. Included components are listed on your quote so you know exactly what you are getting.
More Cummins engines
Trucks that may use the X15
Ready when you are
Looking for a Cummins X15? Send the serial number.
Have your engine serial number, CPL and VIN handy. If you don't, we'll help you find them.
Commercial-Engines.com is an independent supplier of used commercial truck engines and transmissions. Manufacturer names, model names and part numbers are used for identification only and do not imply affiliation with, or endorsement by, any manufacturer. Read the full disclaimer.