The Specifications of a 2006 Cummins 5.9 Liter Diesel

by Rob Wagner
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The Cummins 5.9-liter diesel engine was the first diesel to power light-duty Dodge Ram 2500 and 3500 series trucks. Dodge doesn’t manufacture its own diesel engines, contracting the job to Cummins Inc. of Columbus, Indiana. The 5.9-liter Cummins diesel is perhaps the most durable engine with significant towing power on the automotive market. A heavy-duty version of the 5.9 is used in construction, agricultural and marine equipment.


Dodge, a division of Chrysler LLC, has been selling Dodge Ram trucks equipped with Cummins diesel engines since 1989. Cummins has been producing diesel engines since the early 20th century and more than half of its diesel engine inventory is sold overseas. Dodge sought to match its competitors, Ford and General Motors, with a diesel engine that was engineered like a big rig truck. The result was the 12-valve 5.9-liter in-line six-cylinder model, which was replaced in 1998 with the 24-valve version. The 5.9-liter diesel was replaced by the 6.7-liter model in 2007, according to and

Design Concept

Cummins developed the 5.9-liter diesel by designing it as if it were to be installed in an 18-wheel diesel tractor-trailer big rig. The engine required Dodge to substantially over-engineer its Ram pickups to accommodate the new diesel engine. Dodge beefed up the truck’s suspension and chassis, but more importantly strengthened the six-speed manual and five-speed automatic transmissions and rear axle to handle the stress delivered by the diesel engine's massive torque for towing and payload capacities.


Cummins eschewed the traditional V-8 engine design, instead opting for the in-line six-cylinder for simplicity and easy maintenance. The 2006 5.9 version was made with an all-iron block, steel crankshaft and aluminum intake manifold. The connecting rods were of forged I-beam construction. This allowed an engine lifespan of 300,000 miles before its first major rebuild.

5.9 Specifications

The 24-valve 5.9-liter (359 cubic inches) in-line six-cylinder Cummins diesel varied only slightly from the 12-valve version's dimensions, but delivered more horsepower and torque. Torque is the twisting force generated inside the engine to allow the diesel to haul tremendous payloads. The 2006 5.9-liter version featured a 4.02-inch bore and 4.72-inch stroke. It was equipped with a Holset Turbocharger. The compression ratio was rated at 16.3:1 or the high-performance 17.2:1. Cummins replaced its Bosch P7100 fuel-injection system on the 12-valve models with an electronically controlled Bosch VP44 for the 24-valve versions. Horsepower was rated at 305 in late 2005 for the 2006 Dodge Ram truck, and then boosted to 325 horsepower by early 2007. Most 2006 Dodge diesels were equipped with 325 horsepower. Torque was rated at 610 foot-pounds.


The 2006 Dodge Ram 2500 Series Quad Cab 4X4 pickup truck powered by the 5.9-liter Cummins diesel can achieve 17 mpg in city driving and 21 on the highway. Its gross vehicle weight rating is 9,000 lbs. with a payload capacity of 2,010 lbs. and towing capacity of 12,859 lbs. It’s capable of reaching a quarter-mile in 16.8 seconds at 79 mph and 0 to 60 mph in nine seconds.

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