The International® A26 Truck Engine is a Lightweight Knockout.

At Rush Truck Centers, our mission is to provide you with quality trucks and premier support programs that keep you up and running. That is why we’re excited to offer trucks powered by the International® Trucks A26 engine. Every component has been engineered to deliver uncompromising uptime and fuel efficiency, reduced weight and quieter operation.

International A26 Engine Specs


The International® A26 engine is classified by Navistar as big-bore engine and is available in International LT® Series, RH™ Series, HX™ Series and HV™ Series trucks.   The lightest engine in its class at 2,314 pounds, the 12.4 -liter A26 engine offers better fuel economy and weighs 600—700 pounds less than other big-bore engines on the market.  The A26 produces up to 515 horsepower and 1850 lb.-ft. of torque and delivers up to 4% greater fuel economy than previous generations of the A26 engine.

In October 2021, Navistar announced significant updates to the International® A26 engine, allowing 10% improved fuel economy since the engine’s initial launch in 2016.  The latest enhancements to the new generation of the A26 (2021 GHG) provide additional fuel economy thanks to engine design and system updates such as an increased compression ratio and higher combustion efficiency, optimized engine temperature control, updates to the air management systems, and reduced engine speeds that optimize fuel efficiency without compromising power.

RTC-International-Truck with employee and customer


Our expert sales representatives are available to help answer any questions or to schedule a test drive.  If you’re interested in purchasing an International® truck, search our truck inventory to see our available International® models powered by the A26 engine or contact us to reserve a built slot by clicking the “Inquire About a Truck” button below.

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International A26 Engine


Engine Size: 12.4 liters

Power: 515 horsepower and 1850 lb.-ft. of torque

Engine Weight: 2,314 pounds (600-700 pounds less than 15-liter big-bore engines)

Warranty: Standard two-year unlimited hours or mile warranty plus an optional warranty up to 7 years and 700,000 miles

Maintenance: Oil change service intervals up to 70,000 miles with oil sampling and International Truck approval

Noise Reduction: High Pressure Common Rail fuel system delivers multiple injection events for smooth, quiet operation

Fuel Efficiency: Maximized fuel injection pressure from the 2500 bar (36,300 psi) High Pressure Common Rail (HPCR) fuel system reduces both fuel consumption and emissions

Additional Features:

• Remote updates and parameter setting without bringing a truck in for service

• Cartridge-stye fuel and oil filters for easy service

• Hand primer fuel pump that is 2.5 time larger for easy access and use

• Mass air flow sensor located in fresh air inlet that does not require cleaning

• High temperature fasteners on the exhaust manifolds, turbocharger and heat shields to prevent seizing

International-RH Truck with A26


The A26 has shown its more than up to the task since it was introduced in 2016.  Allowing for increased payload capacity, better fuel economy, and a quiet ride results in higher driver satisfaction and retention.

Here is what others are saying about their A26-powered truck:

“The A26 has plenty of power to pull a bulk trailer of cement powder 650 miles every day, five days a week. Everywhere we go, we run 80,000 pounds. There’s a lot of hills and stop-and-start driving, and it pulls great even when I’m fully loaded.”

- David “Fuzzy” Stafford

“We’ve had zero downtime with these trucks.”

- Steve Sperbeck, General Manger, ERL Intermodal 

ERL Intermodal Testimonial

Leslie Haddenham, Driver Testimonial

Greg Weaver, Driver Testimonial

W.L.A. Testimonial

Bulk Carriers Testimonial


What enhancements were made to the latest generation of the A26 engine?

The latest generation of the A26 engine was announced by Navistar in October 2021.  The A26 (2021 GHG) was built from the MAN D26 engine crankcase and was designed to provide greater fuel efficiency without sacrificing power.  Enhancements provided an additional 4% fuel economy over previous generation achieved through engine design and system updates.

• Compression ratio was improved from 18.5:1 to 20.5:1 to deliver higher combustion efficiency.

• Fuel injection pressure from the 2500 bar high pressure common rail fuel system was maximized.

• Efficiently designed cylinder head coolant passages helped to reduce parasitic loss at the water pump.

• The addition of a variable water pump provided more optimized run time versus constant "on."

• The exhaust gas recirculation (EGR) cooler and intake throttle valve were optimized to create more efficient charge air flow.  A Variable Geometry Turbocharger delivered the desired boost air pressure across a wide range of engine speeds, loads and elevation.

• Horsepower was increased to 515 to provide maximum power when needed and rotations per minute (rpm) were decreased to optimize the amount of fuel consumed during operation.

Is Rush Truck Centers certified to service the A26 engine?

Rush Truck Centers are staffed by factory-trained, ASE-certified technicians, qualified to work on heavy- and medium-duty vehicles of all makes and models.  We also offer Contract Maintenance plans for all makes and models of new and used trucks.  All packages include RushCare Complete, our all-inclusive service management solution to help keep you up and running.

How does the A26 maximize fuel efficiency?

The latest generation of the A26 delivers up to 4% greater fuel economy than its predecessors thanks to maximized fuel injection pressure from the 2500 bar (36,300 psi) High Pressure Common Rail (HPCR) fuel system that reduces both fuel consumption and emissions.

Efficiently designed cylinder head coolant passages, a simplified air management system combined with the Variable Geometry Turbocharger and an oil cooler thermostat bypass also reduce parasitic loss to the water pump and improve fuel economy and performance.  

Is the A26 engine reliable?

The A26 engine has been relentlessly tested with hundreds of thousands of hours of dyno testing and millions of real-world test miles.  It was the first engine in the industry to meet B10 design life standards for 1,200,000 miles.  This means that at least 90% of all A26 engine meet a mileage standard of 1,200,000 miles before the cylinder head or oil pan is removed for a major repair.  The high-pressure common rail fuel pump has undergone six years of testing and has been in production on the MAN® D38 15 liter since 2015, with proven reliability.  Every component is engineered to maximize uptime.

How did International Trucks create the lightest big-bore engine on the market?

The A26 only weighs 2,314 pounds, a full 600-700 pounds less than 15-liter big-bore engines on the market.  This is due to the A26’s Compacted Graphite Iron (CGI) crankcase that provides greater strength and fatigue resistance than traditional gray iron for thinner walls, reduced weight and maximized payload.

Valve covers built from a durable, lightweight composite, aluminum flywheel housing and the simple, single-state design of the turbocharger also contribute to reduced weight and complexity, all without sacrificing power and performance. 

How does the A26 maximize uptime?

Uptime (reliability) was a huge consideration during the A26 engine’s design process.  The A26 features laser-welded, stainless steel, single-stage exhaust gas recirculation cooling system and connecting rods, beefier piston pins, and bushings.  The Variable Geometry Turbocharger (VGT) also comes with a titanium compressor wheel to ensure superior fatigue life.

To improve lubrication and durability even further, the A26 utilizes cooling jets to increase oil pressure and exposes less oil to hot pistons to reduce oil oxidation and improve oil drain intervals.  Aluminum castings, stainless steel tubes, composite valve covers and optional stainless steel oil pans provide long-lasting corrosion protection while all high temperature fasteners feature a permanent coating to prevent seizing. 

What warranty is available on the A26?

The A26 is backed by International® Trucks’ best-in-class standard two-year unlimited hours or miles warranty to keep you on the road for as long as you need to be.  An additional warranty up to 7 years and 700,000 miles is also available. 


How much maintenance does the A26 require?

The recommended engine oil and oil filter replacement interval can extend up to every 70,000 miles with oil sampling and International® Trucks approval.  Additional recommended service intervals for fleets achieving:

• 6.5 or greater mpg: every 50,000 miles

• 5.5 to 6.5 mpg: ever 30,000 miles

• Less than 5.5 mpg: ever 20,000 miles

The fuel filter should be replaced at every oil change or 1,300 miles and the diesel exhaust fluid (DEF) filter should be replaced every 300,000 miles.  It is recommended that the diesel particulate filter (DPF) be cleaned every 600,000 miles/11,000 hours for fleets that achieve more than 6.5 mpg, every 500,000 miles/9,000 hours for fleets that achieve 5.5 to 6.5 mpg, and every 350,000 miles/9,000 hours for fleets that achieve 5.5 or less mpg.

International® Trucks also recommends that Extended Life Coolant be added every 300,000 miles, three years or 6,000 hours of driving and the coolant should be replaced every 600,000 miles, six years or 12,000 hours of driving.  Additionally, the valve lash should be adjusted at 120,000 miles, 300,000 miles and then every 400,000 miles.

Which features of the A26 provide noise-reduction?

The latest generation of the A26 prioritized quieter operation to reduce ambient engine noise and overall improve the in-cab experience for the drive.  The uniquely sculpted crankcase was designed to significantly dampen vibration while the High Pressure Common Rail fuel system delivers multiple injection events for smooth, quiet operation.  By isolating the oil pan and crankcase using a specifically designed rubber gasket, International was able to absorb vibration before it can be applied through the oil pan to further reduce engine noise.

For the LT Series and RH Series, the A26 features a 6-blade fan for even quieter operation. 

Where does the name A26 come from?

The letter “A” in A26 comes from Project Alpha, an internal engineering project at International® Trucks that fundamentally changed the way diesel engines are designed.  The number 26 is shorthand for the engine’s 126-mm diameter piston on the European MAN D26 engine, the base for the A26 engine.