An undisputed leader when it comes to heavy-duty truck engines, Cummins continuously modifies, upgrades, and improves their engines to deliver some of the highest levels of performance and efficiency in the industry.

Built on a proud history of innovation and commitment to quality, Cummins engines are made to address the challenges of the future, just like the Western Star trucks they’re fitted in. We offer the following Cummins diesel truck engines fitted to our Western Star Trucks.

Cummins L9

The L9 is designed to excel in some of the toughest duty cycles. High-strength components and features, like replaceable cylinder liners for easier rebuilding, add life to the engine and add to its residual value.


See what the Cummins L9 is made of.

Configuration6 Cylinder
Displacement8.9 L
Weight (Dry)769 kg (1695 lb)
Torque Range850-1250 lb-ft
HorsepowerUp to 380 HP


The Cummins L9 is fitted to the Western Star 47X.