Let's Fix Your Diesel Today!

Call Now  715-254-2307

Owner, Gary Nilsen, will answer your diesel parts question when you call.

AIR DOG Fuel Systems


Air Dog Fuel Systems

Air Dog II Fuel System / Fuel Air Separator Preporator by Pure Flow Air Dog Diesel is THE FIX for AIR ENTRAPMENT!  Air Dog Fuel Preporator removes air from fuel lines.  

RESULTS: quieter running engine, improved fuel economy and mileage, optimized engine performance, longer injector life, improved throttle response! This patented fuel system efficiently removes air vapor from your diesel fuel for improved fuel economy and performance. 

AirDogII® Fuel/Air Separation System effectiveness is verified by the EPA and CARB Certified Olsen Ecological Laboratory*.

What Make and Model Truck Do You Have?


AirDog® American made, quality driven products provide some of the following benefits:

  • Remove air, water, particulates and vapor from fuel to maintain optimal fuel flow and fuel delivery.

  • Improve fuel economy

  • Reduce exhaust emissions

  • Improve diesel engine performance

  • Increase Horsepower

  • Improve throttle response

  • Increased top end power

  • Longer injector life

  • Smoother idle

  • Optimal fuel system lubrication

AirDog ® II Fuel Air Separation System featuring Demand Flow Technology AirDog ® II is designed to operate at flows and pressures beyond the maximum requirements of the engine. AirDog works by using the Fuel Preparator.

The system can improve diesel engine performance by separating the entrained air from the fuel, also improving  fuel economy through improved injection timing, increased power and better fuel burn.  


   It receives fuel under vacuum from the fuel tank containing entrained air/vapor, particulate contaminates and unknown quantities of water.

   The fuel passes through the water separator which removes the large particulate contaminates that could damage or jam the gerotor fuel pump.

   The fuel, with only entrained air/vapor and tiny particulate contaminates remaining, then enters the fuel pump.

   The fuel, now under positive pressure flow, enters the fuel filter.

   As the fuel passes through the filter media and the remaining particulate contaminates are caught and contained, the entrained air/vapor is also separated.

   Through the positive fuel air separation features of the patented AirDog ® II the separated air/vapor is discharged from the filter and back to the fuel tank through the Primary Air/Vapor Discharge Port.

   The fuel passing through the filter media is now free of contaminates and power robbing air/vapor.

   At pressures and flows able to meet the needs of the engine, it exits the fuel filter through two passageways. First, the fuel for the engine, passes into the fuel pickup tube and on to the engine. Then, the excess fuel not needed by the engine recycles internally through the pressure regulator back to the water separator.

*The effectiveness has been proved over millions of miles and verified by the EPA and CARB Certified Olsen Ecological Laboratory testing under ISO 8178 8 Mode Test criterion.

An engine equipped with the Fuel Preporator has consistently shown a timely injection and will perform at peak power output and efficiency regardless of the fuel filter condition.  




Air Dog Fuel System Fuel Preporator for diesel fuel filtration is available for Ford Powerstroke diesel pickup trucks, Ram Dodge Cummins diesel pickup trucks and GMC Chevy Duramax diesel pickup trucks.