× Cummins Power Stroke Duramax IDI Diesel Tech Service & Repair Diesel Performance Transmission Tech Diesel Tech Towing

5.9L Cummins ISB (24 Valve)

In 1998, the 12v Cummins was phased out in favor of a redesigned 24 valve version of the engine, the 5.9L Cummins ISB (often referred to simply as the 24 valve Cummins). The ISB featured a Bosch VP44 rotary type injection pump until 2003, when the injection system was upgraded to a Bosch high pressure common rail. Power output and performance potential were significantly increased thanks to the common rail injection system. For the 2001 model year, an optional High Output (HO) version of the 24v Cummins was made available, which offered an increase in output - it was only available with a a manual transmission. The 5.9L Cummins was altogether retired mid-way through the 2007 model year, being replaced by the more emissions friendly 6.7L Cummins.

5.9L Cummins 24v Specs, History, & Information

The acronym "ISB" stands for Interact System, B Series. It represents the fact that the engine uses an electronically controlled injection system, and is part of Cummins "B Series" engine family. All 24v Cummins were assembled at the company's Columbus, Indiana assembly plant, the same city in which the "Cummins Engine Company" was founded. For 2004, the engine was selected as one of Ward's "10 Best Engines" for the year. Production of the 5.9L ISB ended completely (all applications) in June of 2009.

High Output 24v Cummins

A high output (H.O. or HO) version of the 5.9L Cummins was available for the 2001 to 2004 model years. For 2001 and 2002, the HO Cummins boasted an additional 10 horsepower and 45 lb-ft of torque. In 2003, the HO model produced a whopping 70 horsepower and 95 lb-ft more than the standard turbodiesel. And for 2004, the optional high output engine claimed 20 horsepower and 45 lb-ft of torque greater than the standard model. The HO Cummins was not available in California, which has historically been a state with stricter emissions regulations than those imposed at the Federal level. The NV5600 6 speed manual transmission was the only transmission available mated to HO models of the Cummins, as at the time the available automatic was not rated with an adequate input capacity. High output models featured higher compression and a unique engine calibration to provide the additional performance.

5.9L Cummins ISB Specs


Cummins 5.9L ISB (commonly referred to as the "24 valve")


Cummins Engine Company, later Cummins Inc

Applications/Production Years:

1998.5 - 2007 Dodge Ram 2500/3500 pickups
Various industrial, agricultural, and motorhome applications of similar period


359.02 CID (359 CID nominal), 5.88 liters (5.9 liters nominal)


Inline 6 cylinder (I-6), 4 cycle diesel

B10 Life:

Note rated

B50 Life:

350,000 miles (~560,000 km)


4.02 in (102 mm)


4.72 in (120 mm)

Bore/Stroke Ratio:

0.85 (undersquare)

Compression Ratio:

Standard models

16.3 : 1

High output models

17.2 : 1

Firing Order:

1 -5-3-6-2-4

Cummins diesel cylinder numbers

Engine Block Material:

Cast iron

Cylinder Head Material:

Cast iron

Injection System:

Direct injection (DI)

1998.5 - 2002

Electronically controlled Bosch VP44 rotary injection pump

2003 - 2007

Bosch high pressure common rail, Bosch CP3 injection pump


Turbocharged, air-to-air intercooler

1998.5 - 1999

Holset model HX35W turbocharger

2000 - 2004

Holset model HY35W type D turbocharger

2004.5 - 2007

Holset model HE351CW turbocharger


OHV, 4 valves per cylinder, solid lifter camshaft

Valve Lash (Clearance):

Exhaust valves

0.020" (engine cold)

Intake valves

0.010" (engine cold)

Cold Start Aid(s):

Intake air grid heater mounted between air horn and intake manifold

Engine Oil Capacity:

12 qts w/ filter change

Engine Oil Spec:

See 24v Cummins maintenance schedule for engine oil viscosity chart


#1/#2 diesel fuel; engine predates modern biodiesel availability[1]


235 - 325 hp @ 2,900 RPM


460 - 610 lb-ft @ 1,600 RPM

Governed Speed:

3,200 RPM

Engine Weight:

~ 1,150 lbs, dry & dressed

Engine Dimensions:


40.0 in


24.9 in


37.9 in

[1] Early 5.9L ISB engines predate modern ULSD regulations and biodiesel compatibility. The engine will run without issue on both fuels, although the effects of extended biodiesel usage are largely sporadic, vague, and/or unknown. Recommend a supplemental fuel additive to increase fuel lubricity regardless of diesel type used, which will prolong fuel system life.

24v Cummins Horsepower & Torque by Model Year

Note - The following ratings are only applicable to Dodge pickups.

Model Year



1998 - 2000

• 215 hp @ 2,700 RPM (auto trans)
• 235 hp @ 2,700 RPM (man trans)

• 420 lb-ft @ 1,600 RPM (auto trans)
• 460 lb-ft @ 1,600 RPM (man trans)

2001 - 2002

• 235 hp @ 2,700 RPM
• 245 hp @ 2,700 RPM (H.O.)

• 460 lb-ft @ 1,400 RPM
• 505 lb-ft @ 1,600 RPM (H.O.)


• 235 hp @ 2,700 RPM
• 305 hp @ 2,900 RPM (H.O.)

• 460 lb-ft @ 1,400 RPM
• 555 lb-ft @ 1,400 RPM (H.O.)


• 235 hp @ 2,700 RPM (CA)
• 305 hp @ 2,900 RPM (std)
• 325 hp @ 2,900 RPM (H.O.)

• 460 lb-ft @ 1,400 RPM (CA)
• 555 lb-ft @ 1,400 RPM (std)
• 600 lb-ft @ 1,600 RPM (H.O.)

2005 - 2007

325 hp @ 2,900 RPM

610 lb-ft @ 1,600 RPM

5.9L Cummins horsepower and torque by model year

5.9L Cummins ISB horsepower & torque by model year
"Alternative" horsepower/torque refers to the H.O. variant