PACCAR PX-9 (Cummins L9-derived)
8.90L Inline-6 turbo diesel • PACCAR (Cummins-licensed)
About the PACCAR PX-9 (Cummins L9-derived)
The PACCAR PX-9 is PACCAR's 8.9L medium-heavy engine — a rebadged Cummins L9 (formerly ISL9, originally ISL 8.3L) manufactured under license. Used in heavier Class 7 medium-duty and lighter Class 8 vocational applications where PX-7's output isn't enough. Like the PX-7, the PX-9 is mechanically identical to its Cummins counterpart with PACCAR-specific software calibration in some specs.
Overview
The PACCAR PX-9 is PACCAR's 8.9L medium-heavy engine — a rebadged Cummins L9 (formerly ISL9, originally ISL 8.3L) manufactured under license. Used in heavier Class 7 medium-duty and lighter Class 8 vocational applications where PX-7's output isn't enough. Like the PX-7, the PX-9 is mechanically identical to its Cummins counterpart with PACCAR-specific software calibration in some specs.
Specifications
- Manufacturer
- PACCAR (Cummins-licensed)
- Displacement
- 8.90 liters
- Configuration
- Inline-6 turbo diesel
- Fuel type
- Diesel
- Horsepower
- 260–380 hp
- Torque
- 720–1250 lb-ft
- Production years
- 2007–present
- Truck classes
- Class 6-8 (vocational)
- Applications
- Heavier medium-duty + vocational Kenworth + Peterbilt
Design and engineering
8.9L Cummins-built inline-6. Identical hardware to Cummins L9. Common rail. SCR + DEF aftertreatment.
Generations and emissions eras
Reliability and longevity
Same as Cummins L9. Strong reliability in vocational duty cycles.
Common problems
Same family as Cummins L9 — DEF system, EGR cooler, NOx sensors.
Pros and cons
✓ Pros
- • Cummins L9 reliability under PACCAR brand
- • Right-sized for medium-heavy
- • Kenworth/Peterbilt integration
⚠ Cons
- • DEF/SCR complexity
- • Brand confusion for parts ordering