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PACCAR MX-13 Big Block Engine

PACCAR MX-13 Big Block Engine in a Pierce Fire Truck driving down the road near trees on a sunny day.

The New Heart of Heavy-Duty Performance

Pierce + PACCAR MX-13




Since 1913, Pierce has been the leading global fire truck manufacturer producing highly customized, carefully designed and engineered pumpers, tankers, aerials and rescue units. 

For more than 60 years, PACCAR has engineered and produced innovative, reliable, productive and efficient heavy-duty diesel engines for customers throughout the world. PACCAR operates two technologically advanced engine research and development centers with 47 engine test cells and a powertrain dynamometer to enhance engine design and manufacturing capabilities.

We are bringing together two premium brands, providing a first-class engine for custom fire apparatus. 

Although the PACCAR engine was going to be a change from the normal for us, we knew the long history of  PACCAR and the affiliation with Kenworth and Peterbilt and having that knowledge, along with having several distributors/shops here in Florence, we knew PACCAR was going to be the right choice for our investment. Since receiving the apparatus, we have been very pleased with its performance and have had no issues with the engine itself or with the DEF system associated with it.

Shannon Tanner
Fire Chief | City of Florence Fire Department
View the Florence Fire Department Aerial

MX-13 Overview

The PACCAR MX-13 engine is built by PACCAR at their Columbus, Mississippi facility. From the CNC machining centers for engine blocks and cylinder heads to robotic assembly, MX-13 engines are manufactured to extraordinarily high standards. In order to achieve excellent  repeatability and high quality, the plant utilizes torque controlled tooling, and all engines are 100% hot tested before they leave the facility.

The PACCAR engine plant in Mississippi opened in 2010 to build PACCAR MX-13 engines exclusively for Kenworth and Peterbilt trucks which are also owned by parent company, PACCAR. In 2021, PACCAR began offering the MX-13 engine to Pierce exclusively for the fire truck industry.  

The PACCAR MX-13 engine incorporates industry-leading design features that improve uptime, optimize fuel economy, reduce maintenance costs and maximize your return on investment. 

Optimized Weight + Fuel Economy

  • Compacted graphite iron castings
    • 75% stronger + 20% lighter than grey iron
  • High pressure common rail fuel injection
    • Improved combustion efficiency

Outstanding Low-End Torque

  • Peak torque at 1,000 rpm

Incredibly Durable

  • Weatherproofed wiring - no cable rub
  • Fractured cap technology - high shear strength

Ultra Quiet + Ultra Smooth

  • Rear engine gear train design reduces noise
  • Maximum engine braking power over a wide range of speeds reducing the need for multiple gear shifts

PACCAR MX-13 Big Block Engine for a Pierce Fire Truck.

PACCAR Engines MX-13 Big Block Engine for Pierce Fire Trucks graphic.


A raised Pierce Fire Truck parked outside on a sunny day showing the PACCAR MX-13 Big Block Engine underneath the cab.



Custom Chassis

Enforcer™, Velocity®


Inline 6-cylinder

Bore x Stroke (mm)

130 x 162


12.9 liters

Dry Weight

2,600 lb

Oil System Capacity

42 U.S. quarts


510 hp

Peak Torque

1,850 lb-ft

Governed Speed

2,200 rpm

Clutch Engagement Torque

937 lb-ft @ 800 rpm


5-yr / 100,000 miles



Easily serviced with extended intervals

  • Over 900 Pierce, Peterbilt and Kenworth service centers in North America
  • Service is available at select Pierce dealerships
  • 98% retail parts availability from Peterbilt and Kenworth
  • Easy-to-access replaceable maintenance parts

A woman servicing a PACCAR MX-13 Engine for a Pierce Fire Truck in a warehouse.