What Engines do Kenworth Trucks Use?

Kenworth trucks are known worldwide for their exceptional durability, performance, and reliability, making them a top choice for drivers and fleets across demanding industries. Their strong build quality and advanced engineering ensure they can handle everything from long haul transport to heavy duty applications with ease.

One of the key factors behind a Kenworth’s performance is its engine. Depending on the model, purpose, and driver requirements, Kenworth trucks can be equipped with different engines, each offering unique strengths in power, efficiency, and torque. Understanding these options can help you choose the right truck for your workload and driving style.

Overview of Kenworth Truck Engine Options

Kenworth partners with some of the most respected engine manufacturers in the trucking industry, including PACCAR and Cummins, to deliver engines that balance power, fuel efficiency, and reliability. These collaborations ensure that every Kenworth is equipped with a drivetrain capable of meeting the toughest performance demands.

Many Kenworth models come with factory-standard PACCAR engines, designed for optimal integration with the truck’s chassis and components. For drivers or fleets with specific needs, optional upgrades such as Cummins engines are available, offering higher horsepower, increased torque, or specialised configurations for heavy duty or longhaul applications. This flexibility allows operators to choose an engine setup tailored to their operational requirements.

PACCAR Engines

PACCAR MX13

The PACCAR MX13 is a flagship engine for many Kenworth longhaul trucks, delivering a horsepower range of approximately 405–510 HP and torque up to 2,500 Nm. It’s engineered for maximum fuel efficiency without sacrificing pulling power, making it ideal for interstate and heavy freight applications. Its design focuses on reduced friction, lightweight components, and advanced combustion technology, which translates to lower operating costs over time.

PACCAR MX11

The PACCAR MX11 is a lighter yet powerful option, offering around 355–445 HP and torque up to 2,250 Nm. Its compact size and reduced weight make it perfect for regional and shorthaul operations where manoeuvrability and efficiency are key. The MX11 is known for its responsive acceleration, smooth performance, and lower emissions profile, making it a smart choice for urban and middistance routes.

Advantages of PACCAR Engines

Both the MX13 and MX11 benefit from PACCAR’s reputation for durability, robust engineering, and seamless integration with Kenworth drivetrains. This integration ensures optimal performance, better fuel economy, and reduced maintenance complexity. In addition, PACCAR’s extensive service network means operators have reliable support and parts availability across Australia and beyond.

Cummins Engines

Cummins X15 Performance Series

The Cummins X15 Performance Series is built for power hungry operations, offering horsepower ratings up to 605 HP and torque up to 2,800 Nm. It’s designed for heavyhaul applications, steep gradients, and challenging terrains where maximum pulling capacity is essential. Advanced engine braking and superior load handling make it a favourite among operators tackling Australia’s toughest routes.

Cummins X15 Efficiency Series

The Efficiency Series focuses on optimising fuel economy for long distance, linehaul transport. With horsepower in the 400–500 HP range and torque up to 2,500 Nm, it delivers smooth, consistent performance while keeping operating costs down. Features like predictive cruise control and advanced combustion technology help maximise kilometres per litre without compromising reliability.

Cummins L9 / B6.7

For medium-duty Kenworth models, the Cummins L9 and B6.7 engines offer a balance of power, reliability, and efficiency. The L9 delivers 260–450 HP, while the B6.7 ranges from 200–325 HP, making them suitable for local delivery, regional freight, and vocational applications. These engines are known for their robust build, low maintenance demands, and strong aftermarket support.

Matching Engine to Application

Choosing between PACCAR and Cummins engines for your Kenworth comes down to balancing performance needs, operating conditions, and cost efficiency.

Load Requirements

• Heavy loads & extreme hauling: Cummins X15 Performance Series or PACCAR MX13 for maximum horsepower and torque.

• Medium duty or lighter freight: PACCAR MX11, Cummins L9, or B6.7 for reliable performance without overpowered specs.

Route Type

• Longhaul interstate runs: PACCAR MX13 or Cummins X15 Efficiency Series for fuel economy, smooth power delivery, and reduced fatigue over long distances.

• Regional or shorthaul: PACCAR MX11 or Cummins L9 for quick acceleration, lighter weight, and nimble handling.

• Heavyhaul or demanding terrain: Cummins X15 Performance Series for unmatched pulling power and durability.

Fuel Economy Needs

• Prioritising efficiency: PACCAR MX13 or Cummins X15 Efficiency Series with advanced fuelsaving tech.

• Balanced power and economy: PACCAR MX11 or Cummins L9.

Maintenance Preferences

• PACCAR advantage: Seamless integration with Kenworth drivetrains, optimised service intervals, and strong dealer network support.

• Cummins advantage: Broad industry familiarity, versatile applications, and widespread independent service options.

Emissions & Environmental Considerations

Kenworth trucks, whether equipped with PACCAR or Cummins engines, are designed to meet strict environmental regulations without compromising performance.

• Regulatory Compliance

All current engines comply with EPA (U.S.) and Euro 6 emissions standards, ensuring reduced NOx (nitrogen oxides) and particulate matter output.

• EmissionReducing Technologies

SCR (Selective Catalytic Reduction): Uses a urea-based DEF (Diesel Exhaust Fluid) to convert NOx into harmless nitrogen and water vapour, significantly cutting harmful emissions.

DPF (Diesel Particulate Filter): Captures and stores soot from exhaust gases, then burns it off during regeneration cycles, helping meet particulate matter limits.

• Fuel Efficiency & Sustainability

Advanced engine management systems balance power output with fuel economy, reducing overall CO₂ emissions. Many models also support renewable diesel compatibility, offering a greener fuel option.

Maintenance & Service Support

When it comes to owning a Kenworth truck, the engine you choose should not only deliver performance but also be backed by strong maintenance and service support. Accessibility to expert servicing plays a huge role in keeping your truck on the road and minimising downtime. Kenworth’s extensive dealer network, along with PACCAR and Cummins’ authorised service centres, ensures that help is never far away, whether you are on a local run or hauling freight across the country.

Both PACCAR and Cummins engines benefit from excellent parts availability, with genuine components stocked across a wide network of suppliers. This means repairs can be carried out faster, without long waits for essential parts. In addition, service centres are staffed by factory-trained technicians who use the latest diagnostic tools and follow manufacturer-approved procedures, ensuring repairs and maintenance are completed to the highest standard.

Many Kenworth dealers also offer preventive maintenance programs designed to optimise engine performance and identify issues before they become costly problems. These programs not only extend the lifespan of the engine but also improve fuel efficiency and reduce unexpected breakdowns. By choosing an engine with strong service and support options, you can ensure your Kenworth runs reliably and delivers maximum value over its lifetime.

Conclusion

Kenworth’s diverse range of engine options gives operators the flexibility to choose a powertrain that perfectly aligns with their business needs. Whether you prioritise raw power for heavyhaul applications, fuel efficiency for long-distance linehaul work, or reliability for regional and medium-duty operations, there’s a PACCAR or Cummins engine designed to deliver.

Because every transport operation is unique, it’s worth consulting with an experienced Kenworth dealer to review your routes, payloads, and operational priorities. Their expertise can help you match engine specifications to your performance goals, ensuring you get the most out of your truck while maximising efficiency and profitability.