X12 (2021) for Emergency Vehicles

Power 350 - 500 hp
261 - 373 kW
Torque 1250 - 1700 lb-ft
1695 - 2305 N•m
Certification EPA 2021

Select an Application

Available Regions

US and Canada,  Russia,  Africa & Middle East,  Mexico,  Philippines,  Singapore,  Brazil,  Bolivia,  Uruguay,  Paraguay,  Argentina,  Colombia,  Central America,  Europe,  Korea,  Japan


Cummins has been powering the fire service since 1937. The 2021 X12 engine was designed to serve the fire & emergency market, with a focus on improved reliability and better performance, while meeting more stringent EPA Greenhouse Gas standards. We’ve been able to optimize the existing technology we are experienced in, without the need for additional emissions equipment. 

The X12 keeps the same industry leading power to weight ratio as the lightest heavy duty engine on the market. It also retains the industry leading 1500 hour or 18 month oil and filter change intervals. Additionally, the optional air compressor resonator provides reduced noise inside and outside the cab. 

For a more three-dimensional look at the modifications and improvements made to the 2021 X12, watch this video.

X12 Specifications


Configuration  Inline 6 
Displacement  720 CU IN / 11.9 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)   250 LB / 930 KG 
Aftertreatment Weight**  173 – 191 LB / 78-87 KG 

** Depending on configuration 



Engine Model Max. Power HP (kW)  Peak Torque lb-ft (Nm) @ RPM  Governed Speed (RPM) 
X12 500  500 (373)  1700 (2305) @ 1000  2000
X12 455  455 (339) 1700 (2305) @ 1000 2000



  • Cummins on Every Corner – Over 3,700 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. 
  • Cummins Guidanz™ — This app allows you to read check engine lights and share via email with your service provider. 
  • Longer Optional Extended Coverage — Unmatched full-engine coverage options of up to eight years are available, for peace of mind and predictable maintenance costs. 
  • Get the Latest —You can stay up to date with quarterly articles in the First Responder newsletter

X12 Maintenance Intervals


Oil and Filter 1500 hours / 12 months
Fuel Filter 1200 hours / 12 months
Valve Lash Check 6,750 hours
Crankcase Breather Filter Maintenance Free

*Intervals above reflect typical usage, extended maintenance intervals may be available, please check QuickServe Online.  

Consult your chassis and engine owner’s manuals for more information. 

To access our complete brochure library, click here.
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