The International® A26 Truck Engine is a Lightweight Knockout.

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.

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.

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.  

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.

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. 

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. 

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. 

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.

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. 

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.