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The 5.9L Cummins was first put in Dodge pickup trucks in 1989, however here we will focus on the last half of its life where the engine switched to a 24 valve system. This transition occurred in 1998.
The in-line 6 cylinder Cummins engine is developed and manufactured by Cummins out of Columbus, Indiana, and this specific engine is modified to meet the specific demands of Dodge Ram customers. This engine was available in Dodge Ram 2500 and 3500 pickups and cab chassis, with cab chassis being more desirable for commercial applications.
The 24 V, or 24 valve, 5.9L Cummins was first available in Dodge Ram trucks starting in 1998. This engine used an intercooled Holset turbocharger unit.
The engine was also initially introduced using an electronically controlled rotary injection pump created by Bosch. This lasted until 2003 when the engine switched over to a high pressure common rail solution that enabled many significant improvements for this engine.
Eventually the engine gave way to the 6.7L Cummins in 2007, with emissions compliance being a major driving point for the switchover. Given that the 5.9 L Cummins was in production for such an extended amount of time, this engine had great reliability as most of the issues were able to be investigated and corrected.
The engine also provided peak torque at relatively low RPMs which is great for driveability. The inline 6 cylinder engine and the design modifications required to create an inline 6 cylinder that fits into a modern truck certainly provides a different feel than the V8 offered by its competitors, and many diesel enthusiasts prefer this configuration.
The natural balance of an inline 6 cylinder engine is also a big selling point for this engine.
5.9L Horsepower and Displacement Specs
This engine when first introduced in 1998 offered 235 horsepower at 2700 RPM and 460 lb-ft of torque at 1600 RPM in its manual transmission offerings, while providing slightly less with the automatic transmission options.
There was then a major increase in performance capability in 2003, coinciding with the fuel system switch from rotary pump injection system to high pressure common rail. The result was a jump to 305 horsepower at 2900 RPM and 555 lb-ft of torque at 1400 RPM.
In 2005 the engine power was again increased, this time jumping up to 325 horsepower at 2900 RPM, as well as an increase in peak torque to 610 lb-ft at 1600 RPM. The 5.9L engine, or 359 cubic inches for those more comfortable with standard units, had a bore of 4.02 inches and a stroke of 4.72 inches.
Head and Block Construction
The 5.9L engine used the traditional cast iron block and cylinder head, which in fact are the same materials still used in the 6.7L Cummins engine that eventually replaced the 5.9L. Also, as mentioned earlier, this is a 24 valve engine. The architecture is overhead valve (OHV) with a solid lifter camshaft.
The 5.9L Cummins engine was a mainstay in Dodge Ram trucks for almost 20 years. About halfway through it switched to the more modern version that was a 24 valve system compared to the original 12 valve system. Then after 5 years with the 24 valve system, another significant modification was introduced in terms of the common rail injection system.
The Cummins 5.9L inline six cylinder configuration makes it unique versus competitors in this market, and provides a competitive advantage in the eyes of many. Eventually this engine had to be retired as stricter emissions standards and new technologies required that a new platform be created, the 6.7L Cummins.