Commercial Truck Engine

PACCAR PX-7 (Cummins B6.7-derived)

6.70L Inline-6 turbo diesel • PACCAR (Cummins-licensed)

Production 2007–present Class 5-7 220–360 hp

In production

Displacement

6.70L

Configuration

Inline-6 turbo diesel

Power range

220–360 hp

Production

2007–present

About the PACCAR PX-7 (Cummins B6.7-derived)

The PACCAR PX-7 is PACCAR's 6.7L medium-duty engine — a rebadged Cummins B6.7 manufactured under license. PACCAR doesn't build the engine itself; Cummins manufactures it and PACCAR labels it as PX-7 for use in Kenworth and Peterbilt medium-duty trucks. The PX-7 is mechanically and electronically identical to a Cummins B6.7 — same architecture, same aftertreatment, same maintenance schedule. PACCAR markets the rebrand to integrate the engine more tightly with Kenworth/Peterbilt dealer support and parts ecosystem.

Overview

Specifications

Manufacturer: PACCAR (Cummins-licensed)
Displacement: 6.70 liters
Configuration: Inline-6 turbo diesel
Fuel type: Diesel
Horsepower: 220–360 hp
Torque: 520–800 lb-ft
Production years: 2007–present
Truck classes: Class 5-7
Applications: Medium-duty Kenworth + Peterbilt

Design and engineering

6.7L Cummins-built inline-6 turbo diesel. Identical to Cummins B6.7 in hardware. PACCAR-specific software calibration in some configurations. Common rail injection.

Generations and emissions eras

PX-7 (B6.7-based)

2007–2013

EPA 2010-era platform.

PX-7 with SCR

2014–present

SCR + DEF aftertreatment added.

Reliability and longevity

Same as Cummins B6.7. Wide third-party rebuild network thanks to Cummins parts commonality.

Common problems

Same family as Cummins B6.7 — DEF heater failures, NOx sensor degradation, EGR cooler at 200K+ miles.

Pros and cons

✓ Pros

• Cummins reliability under PACCAR badge
• Kenworth/Peterbilt dealer support
• Wide aftermarket parts

⚠ Cons

• DEF system issues industry-wide
• Branding can confuse parts ordering

Trucks that use this engine

Kenworth K270 (cabover)Class 6 Kenworth T270Class 6 Kenworth T370Class 7 Peterbilt 220 (cabover)Class 6-7 Peterbilt 337Class 7 Peterbilt 348Class 7-8

Frequently Asked Questions

What is the PACCAR PX-7 (Cummins B6.7-derived)?

What trucks use the PACCAR PX-7 (Cummins B6.7-derived)?

The PACCAR PX-7 (Cummins B6.7-derived) is used in 6 truck models we cover: Kenworth K270 (cabover), Kenworth T270, Kenworth T370, Peterbilt 220 (cabover), Peterbilt 337, Peterbilt 348. It primarily appears in Class 5-7 applications for Medium-duty Kenworth + Peterbilt.

Is the PACCAR PX-7 (Cummins B6.7-derived) reliable?

Same as Cummins B6.7. Wide third-party rebuild network thanks to Cummins parts commonality.

What are the common problems with the PACCAR PX-7 (Cummins B6.7-derived)?

Same family as Cummins B6.7 — DEF heater failures, NOx sensor degradation, EGR cooler at 200K+ miles.

How does the PACCAR PX-7 (Cummins B6.7-derived) compare to competitors?

PACCAR PX-7 (Cummins B6.7-derived) competes with other major commercial diesel engines including Cummins B6.7, Ford Power Stroke 6.7L, and Duramax 6.6L. Each has different strengths in fuel economy, reliability, parts availability, and resale impact. See the pros and cons section above for specific comparisons.

What's the resale impact of buying a truck with the PACCAR PX-7 (Cummins B6.7-derived)?

Engine choice significantly affects truck resale value. Cummins-equipped trucks typically command the highest resale premium across all manufacturers, while emerging engines (International A26) or troubled legacy engines (MaxxForce 13) command lower resale.

Operating PACCAR PX-7 (Cummins B6.7-derived)-equipped trucks? Talk to us.

(682) 978-8641 Send a message