Hours:

  • Mon: 8:00AM - 6:00PM
  • Tue: 8:00AM - 6:00PM
  • Wed: 8:00AM - 6:00PM
  • Thu: 8:00AM - 6:00PM
  • Fri: 8:00AM - 6:00PM
  • Sat: Closed
  • Sun: Closed

4007 Westfax Dr
Suite D, Chantilly, VA 20151

Your car or truck's AC system is under extreme pressure and the thermal expansion valve or orifice tube monitors the amount of pressure and the temperature of your A/C system. It calculates the precise amount of refrigerant that can safely go into the evaporator. A failing expansion valve or orifice tube often causes a vehicle's air conditioner to blow hot air.

Replace or Repair

  • Expansion Valves: Too much refrigerant causes your evaporator to get too cold whereas too little refrigerant would result in inadequate cooling. The expansion valve is a complex valve that regulates refrigerant flow. This process of metering the refrigerant adjusts the flow according to the temperature of the refrigerant in the evaporator coil. Talk to one of the pro mechanics at High-Tech Auto and Truck Center, as this part can be replaced on its own and does not require the entire replacement of the AC assembly.
  • Orifice Tubes: Unlike the expansion valve, the orifice tube is a simple fixed device with no moving parts. It therefore cannot vary the flow of refrigerant into the evaporator, but rather causes a permanent restriction in the system. However, like the expansion valve the orifice tube regulates refrigerant flow through the system and filters debris which may come through in its screen. Often fixing a "bad orifice tube" requires replacing the entire evaporator assembly.

What Our Customers Say

I had my 2018 Audi Q7 windshield replaced at Yellowstone Auto Glass and they provided excellent service from start to finish. Scheduling was quick and easy. They coordinated with my insurance company to get approval for the best OEM parts for my Audi Q7. The technician (Robert) came to my location to do the work. He was AWESOME! Robert took the time to thoroughly explained the work before starting. My car had generated may error codes from all of the electronic sensors. He explained to me all the possible outcomes in order for me to make an informed decision. He answered my numerous questions very patiently, professionally, and thoroughly. Robert performed the entire work in under 2 hours and that included windshield replacement and complete recalibration of the camera/safety sensor system. He clearly is an expert in this line of work. I couldn't be happier with my experience using Yellowstone. I highly recommend them.

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~ , 01/11/2026

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Serving Areas

High-Tech Auto and Truck Center

4007 Westfax Dr
Suite D
Chantilly, VA 20151

Certifications and Associations

  • ASE (Automotive Service Excellence)
  • ATI
  • TechNet
  • High-Tech
  • BG Products


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