What are Maxxforce, Navistar N-Series and A26 engines? International & Navistar Engines Explained.


This blog is an in-depth overview of different International and Navistar engines and we also go over some helpful tips if you are looking to buy a used International truck.  

With International trucks you are going to have a couple different engines based on year, make, model and emissions.  

International engines are popular in medium duty and heavy-duty International trucks. The following types of vehicles have International engines: 

    • Vocational 
    • School buses 
    • Motorhomes 
    • Tow trucks 
    • Municipality vehicles 
    • Over-the-road Tractors 

    The three engines you will find in an International powered vehicle are:   

    1. International Maxxforce  
    2. Navistar N-Series  
    3. Navistar A26 Series 

      The International Maxxforce Engine 

      This engine is commonly known to have issues with the EGR / DPF system which is why it was taken off the market; it was known as the international Maxxforce EGR Diesel Defect lawsuit. The EPA 07/10 version relied very heavily on the EGR usage, which is why the system was not reliable in meeting emission standards.  

      The high flow EGR system made the usage of EGR to control the emission output which put strain on the aftertreatment system and caused engine failures.  

      The system is highly dependent on you maintaining your aftertreatment system by periodically ensuring you have a proper working system.  

      7 Tips if you have a Maxxforce engine 

        • Ensure the EGR System is operating properly.  
        • Ensure that there are no EGR cooler leaks.  
        • Make sure the engine does not have any fault codes that prevent a driving regen.  
        • Clean or replace the MAP (Manifold Air Pressure) Sensor 
        • Clean or replace the IAT (Intake Air Temperature) Sensor 
        • Inspect and clean your intake throttle valve 
        • Run a forced DPF regen to ensure all of the soot is cleaned out of the DPF filter.  

      The International N-Series Engine

      International designed the N-Series from 2014+ engine to comply with the new EPA regulations. These engines are equipped with the EGR, DPF, and SCR. This new aftertreatment system is improved to ensure you have reliability with the system.

      The system doesn’t rely on only the EGR to reduce NOx, so this is where the SCR system will help reduce emissions to pass the EPA13 Standards.  

      It’s always recommended to thoroughly check all components of your aftertreatment periodically.

      You have more components to look after with the SCR system being added. This includes additional NOx sensors, SCR temperature sensors, DEF pump, DEF tank, DEF quality and level sensors. 

      International A26 Engine Coverage

      The International A26 Engine 

      Navistar classifies this engine as the big bore, with a displacement of 12.4 L. The horsepower ranges from 370-475 and the torque from 1350-1750. This engine produces 5% more efficiency than the older 2017 N13 engine.  

      What improvements did International make?  

        • Improved lower end, larger piston pin, connecting rod and bushings 
        • New cylinder head with enhancements 
        • New compacted graphite iron crankcase design for greater strength 
        • Engine braking power increased by up to 67%  
        • High pressure common rail fuel system that produces maximum pressure to reduce emission and improve fuel mileage 
        • Variable geometry turbo that enhances the low-mid-high-power range through all the gears 
        • Low idle fuel consumption 

      The A26 Engine does have a full aftertreament system that consist of the following components: 

        • EGR 
        • EGR Cooler 
        • VGT 
        • DOC Filter 
        • DPF Filter 
        • SCR Filter 
        • DEF Tank 
        • ACM Module 
        • NOx Sensors 
        • DEF Quality Sensors 
        • Aftertreatment Temperature sensors 

      International has improved the quality and the reliability of their engines over the years.  

      It’s always recommended to perform routine checks to ensure your system is running and you have optimal performance to keep you from having downtime.  

      Looking to buy an International truck? 3 helpful tips!  

      1. If you are buying a used International truck it is important to get all of the history of what was replaced if possible. 
      2. Ensure you don’t have active fault codes, if you do it’s recommended to find the root cause before you commit to the purchase. 
      3. Run a forced regen and ensure it completes! You can run a forced dpf regen with a few different tools and ensure the DPF temperatures are within specifications and that it completes one. If regen does not start then this may lead to unnecessary down time.  

        At OTR, we reimaged what diagnostics look like. We empower you with the control to be able to perform a simple reset or give you possibilities to perform advanced functions such as starting a forced DPF regen.  

        Until next time! 👋
        Stay safe, stay healthy & be blessed 

        Looking to learn more? Check out our other blog posts. 

          OTR diagnostics allows you to read and reset fault codes, view live data, and run advanced diagnostic functions, including forced DPF regen with your mobile phone or tablet. Select which engine you have for your diagnostic package. 

          The OTR reset tool is specific to which model and engine you have. Select which engine for more specific details. 


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