X12 (2018) For Emergency Vehicles

Power 455 - 500 hp
339 - 373 kW
Torque 1695 - 1700 lb-ft
2298 - 2305 N•m


Built to serve the fire service, the Cummins X12 provides the highest power-to-weight ratio of any heavy duty engine.

  • Up to 500 HP and 1700 lb-ft of torque 
  • 600 lbs less for flexible cab design 
  • Special emergency vehicle calibrations

Improvements to the compression braking provides 20% stronger braking for greater vehicle control. With over 100,000 engines in service around the world with over 1 billion miles of real-world experience, you can count on the Cummins X12. 

What's New for Fire/EV 2021?

NOTE: For all engines and options available, horsepower may be limited by the truck OEM

REPTO - Available - Torque limit of 466 lb-ft continuous, 516 lb-ft intermittently, gear drive ratio is 1.18:1, rotation is opposite of the crankshaft

FEPTO - Available - Torque limit up to 625 lb-ft


Configuration Inline 6
Displacement 720 CU IN 11.8 L
Lube Oil Capacity 42 QT 39.8 L
Biodiesel Compatibility Up to B20
Engine Braking Horsepower Up to 450 HP @ 2300 RPM
Idle Speed 600-800 RPM
Governed Speed 2000 RPM
Engine Weight (Dry) 2050 LB 930 KG
Aftertreatment Weight** 173-191 LB 78-87 KG

**Depending on configuration

  Advertised HP (kW) @ RPM Peak Torque LB-FT (N•M) @ RPM
X12 500 500 (373) @ 1900 1695 (2298) @ 1000
X12 455 455 (339) @ 1900 1700 (2305) @ 1000
  • Cummins on Every™ Corner – Over 3,500 authorized locations across North America, to support parts and service needs.

  • Peace of Mind – Base warranty backed by Cummins for a full 5 years/100,000 miles, whichever comes first. Up to 8 years of optional full engine coverage, including injectors.

  • Cummins Guidanz™ and INLINE™ Mini – Read real time engine data and email fault information from your smart phone to speed up the repair process.

  • QuickServe™ Online Mobile – Provides complete parts and service information based on specific ESNs.

  • Connected Diagnostics™ – Wirelessly connects Cumminspowered emergency vehicles to product experts at Cummins for immediate diagnosis of an engine system fault.

  • Easier Maintenance – The compact design of the X12, together with easy service points for scheduled maintenance increases uptime.

  • Get the Latest – Need more information about the Cummins X12 engine or Cummins Onan generators? Visit www.cummins.com/engines/fire-and-emergency. You can also stay up to date with quarterly articles in the First Responder newsletter at firstresponder.cumminsnewsletters.com.

Maintenance Item Hours Months
Oil and Filter 1,000 12
Fuel Filter 30,000 6

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