ISX12N (2018)

Power 320 - 400 hp
239 - 298 kW
Torque 1150 - 1450 lb-ft
1559 - 1966 N•m
Certification EPA 2018

Select an Application


The 2018 ISX12N continues the evolution of emissions-leading natural gas engines from Cummins Westport. Certified to the California Air Resources Board and Environmental Protection Agency's (EPA) Optional Low NOx emissions standard of 0.02 g/bhp-hr, it has 90% fewer NOx emissions than the current North American EPA standard. With 400 hp / 1,450 lb-ft torque, and near-zero emissions, the ISX12N is well suited for heavy-duty regional-haul truck, vocational, refuse applications, and motorcoach.

Reduced Emissions from Heavy Duty Trucks

  • Reduces smog forming NOx emissions by 90% vs. EPA NOx Standard
  • Can operate with 100% CNG, LNG, or renewable natural gas (RNG)
  • Significant GHG reductions with the use of RNG. Learn more with Cummins Westport GHG Emissions Calculator.
  • Natural gas is the lowest carbon fuel available, with abundant domestic supply and stable pricing
  • Fueling infrastructure in place and growing
  • No infrastructure changes are required for current natural gas fleets


NOx emission 0.02 g/bhp-hr. (90% below EPA)
Maximum Horsepower 400 HP (298 kW)
Peak Torque 1,450 LB FT (1,966 Nm)
Goverened Speed 2100 RPM
Type 4-cycle, spark-ignited, in-line
6 cylinder, turbocharged, CAC
Engine Displacment 762.2 CU IN (119.9 Liters)
Number of Cylinders 6
Operating Cycles 4
Net Weight (dry) 2,650 LB (1,202 KG)
Fuel Type CNG/LNG/Biomethane
Aftertreatment Three-Way Catalyst
Base Warranty 2 Years, 250,0000 Miles (402,336 KM)
  • Heavy Duty Class 8 performance and efficiency
  • New electronic engine, ignition, and On-Board Diagnostics (OBD) emission control features. 
  • New engine control module – ECM model number CM2380.
  • Closed Crankcase Ventilation system for more complete combustion and lower emissions

Overall, maintenance for the ISX12N  is similar to that of diesel engines, but there are a few key differences:

Maintenance Item^ Hours Distance Months
Oil And Filter* 500 25,000 mi (40,000 km) 6
Spark Plugs 1,000 50,000 mi (80,000 km) 12
Coolant Filter 1,500 75,000 mi (120,000 km) 12
Overhead Set Adjustment** 3,000 150,000 mi (240,000 km) 2 yrs
Cooling System Flush 6,000 300,000 mi (480,000 km) 2 yrs
Engine Brake Adjustment 6,000 300,000 mi (480,000 km) 2 yrs
Closed Crankcase Ventilation Filter 10,000 500,000 mi (800,000 km) 5 yrs
Ignition Coil Extension 10,000 500,000 mi (800,000 km) 5 yrs
Air cleaner / element Follow manufacturer's published recommendations

Consult your Owners or Operation and Maintenance manual for the complete daily and routine maintenance schedule.

^Based on a duty cycle of 50 mph / 80 kph average speed. Distance intervals may decrease based on average speed.
*Requires natural gas engine oil. These intervals apply to normal duty line haul truck and motor coach applications using CES 20085 or 20092 natural gas oil. For customers using CES 20092 natural gas engine oils only, the recommended interval is 40,000 mi (64,000 km) for vehicles with average road speeds greater than 25 mph (40 kph).
**Initial overhead set adjustment at 1,000 hours.

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