Air Entrainment in Diesel Fuel: AirDog Separation System Is The Key

Does your diesel truck ever seem, well a little gassy? Hiccups and burps interupting the power of your rig? Fuel delivery and filtration systems are an important aspect to any diesel and can be easily overlooked when blinded by shiny new turbos, exhaust stacks, ECUs, etc.

If fuel delivery hiccups are causing your diesel truck heartburn, you could be experiencing a phenomenon known as air entrainment. PureFlow AirDog has a solution.

Air Entrainment? What’s That?


Sloshing and agitation trap air in diesel fuel. Entrained Air bubbles are visible being drawn up the pick up.

In layman’s terms when diesel fuel is agitated, sloshed, or pumped, tiny air bubbles are worked into the viscous liquid. These bubbles can be too small to view with the naked eye but become trapped in solution.

Because diesel is a higher viscosity than gasoline, the bubbles do not rise to the surface as easily, the fuel in your tank is drawn up the pickup before the air can rise to the surface. Once in your fuel lines the air entrained in the diesel can form larger bubbles that will interupt the flow of fuel to the engine.

The AirDog Fuel Preporator Has Your Engine Covered


The AirDog Fuel Preporator pump separates the entrained air from the fuel.

The PureFlow AirDog Fuel Preporator acts like a traditional vaccum pump fuel filter until it is turned on. It becomes immediately apparent how the AirDog removes entrained air from the fuel delivered to the engine, and recirculates the air back to the tank along with a minimal amount of fuel.

With the newly filtered flow of diesel making its way to the transfer pump, fuel pressure is restored to a correct level preventing pump cavitation and hiccups. Consistent fuel delivery is quite important for more aspects than your pump, and it can even improve more than you may have thought for your diesel engine, no matter the application.

Why Should I Upgrade My Filter?


The AirDog Fuel Preporator features all the normal features of a vacuum pump filter but also removes entrained air bubbles from diesel fuel.

The benefits to using the AirDog Fuel Preporator are manifold:

  • Removes Air and Vapor from Diesel Fuel
  • Pure Diesel Fuel Reaching Engine
  • High Flow Rates of Fuel to Engine
  • Longer Injector Life
  • Increased Injection Pump Life
  • Increased Fuel Economy
  • Optimized Engine Performance
  • Increased Torque Output
  • Improves Throttle response

The AirDog Fuel Preporator is approved for use by both the EPA, and CARB so no added worries about emissions standards. The kit includes everything necessary for installation and can be applied to frame rails without drilling!

The AirDog is offered in three configurations: the Original AirDog, the AirDog II featuring and adjustable regulator, and the AirDog II-4G with a dual feed gerotor motor. The last AirDog being the highest output model. According to PureFlow AirDog: “AirDog® II-4G is designed to operate at flows and pressures beyond the maximum requirements of the engine.”


The flow of diesel to the transfer pump is free of entrained air bubbles, improving consistency of fuel delivery. Entrained air and excess fuel are returned to the tank.

About the author

Trevor Anderson

Trevor Anderson comes from an eclectic background of technical and creative disciplines. His first racing love can be found in the deserts of Baja California. In 2012 he won the SCORE Baja 1000 driving solo from Ensenada to La Paz in an aircooled VW. Trevor is engaged with hands-on skill sets such as fabrication and engine building, but also the theoretical discussion of design and technology. Trevor has a private pilot's license and is pursuing an MFA in fine art - specifically researching the aesthetics of machines, high performance materials and their social importance to enthusiast culture.
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