5.9L 12 Valve I6 (1989-1998)

5.9L 12 Valve Inline-6 Cummins (1989-1998)

Cummins 5.9L 12 Valve Turbodiesel Engine

The Cummins 5.9L Turbodiesel Engine, also known among the diesel community as the "12 Valve" was the first diesel engine in the Dodge Ram lineup starting in 1989. The 1st Generation Ram 2500s and Ram 3500s utilized this engines 160 HP and 400 lb-ft of torque as well as its incredible dependability.
This engine is highly sought after in the diesel community not only for its ease of maintenance and repair, but also for its superior build quality. The engine came off the production line massively under-powered, as the stock internals were found out to be much stronger then they were initially rated for.
From 1989 to 1993, the 12 Valve was paired with VE44 Injection pump, which was succeeded by the P1700 Injection Pump. The P1700, which is commonly reffered to as the "P-Pump," is renowned by the diesel community for both its durability and its power potential.

Common Engine Issues and Resolutions

The Killer Dowel Pin
The Largest and most detrimental flaw of the 12 Valve Cummins has to do with a steel dowel pin located in the front timing gear-case. Due to the constant vibrations and heat cycles of the engine, the pin tends to wobble out and fall into the gear-case. When this happens, it is more than likely that the pin will hit or jam into one of the timing gears causing it to either shoot out and through the side of the case, or destroy and jam the gears. This causes the Cams, valves, and pistons to quite literally self-destruct, and cause a cataclysmic engine failure.
Fortunately for 12 Valve owners, there is a repair kit that costs under 100$ to help replace and easily secure this pin, thus avoiding this issue altogether. If you would like to purchase this kit, or look at other ones, click here.

Common Data across all Years

Years:	1989-1998
Bore x Stroke:	4.02" x 4.72"
Head Material:	Cast iron
Block Material:	Cast iron
Compression Ratio:	17.0 : 1
Firing Order:	1 - 5 - 3 - 6 - 2 - 4
Style of Injection:	Bosch VE44 Rotary Injection Pump (1989-1993) Bosch P7100 Injection Pump (1994-1998)
Turbocharger:	Holset H1C Non-Intercooled Turbocharger (1989-1991) Holset H1C Intercooleded (air to air) Turbocharger (1991-1993) Holset WH1C / HX35 Intercooled (air to air) Turbocharger (1994) Holset HX35 Intercooled (air to air) Turbocharger (1994-1998)
Weight:	1,100 lbs.
Oil Capacity:	12 Quarts, with filter
Governed RPM:	2,700 RPM
Transmissions typically paired:	Getrag G360 5-speed Manual 47RH 4-speed Automatic New Venture NV4500 5-speed Manual

HP and Torque Configurations

1989-1993	160 HP @ 2,500 RPM	400 lb-ft @ 1,600 RPM
1994-1995	160 HP @ 2,500 RPM (auto trans) 175 HP @ 2,600 RPM (manual trans)	400 lb-ft @ 1,500 RPM (auto trans) 420 lb-ft @ 1,500 RPM (manual trans)
1996-1998	180 HP @ 2,500 RPM (auto trans) 215 HP @ 2,600 RPM (manual trans)	420 lb-ft @ 1,500 RPM (auto trans) 440 lb-ft @ 1,500 RPM (manual trans)