2017 Audi A3 Quattro A/C Expansion Valve

Choosing An A/C Expansion Valve

An A/C expansion valve meters refrigerant into the evaporator. The replacement needs the correct valve design, refrigerant application and line connections for the system being serviced. Block-style valves and other configurations use different housings and sealing arrangements, so a similar shape alone is not enough to choose the part.

On vehicles with separate front and rear evaporators, identify the circuit needing service. The two locations can use different valves and may be reached through different parts of the vehicle.

How A Thermal Expansion Valve Works

The thermal expansion valve regulates the refrigerant supply at the evaporator inlet. The pressure change allows refrigerant to cool and absorb heat from air passing through the evaporator. The valve works within the refrigerant circuit; it is not the dashboard control that selects cabin temperature.

Some A/C systems use a fixed orifice tube instead of a thermal expansion valve. They are different metering arrangements, and the replacement should match the design installed in the vehicle.

Connections And Seals For An AC TXV

A-Premium offers expansion valves with different body and connection styles for selected applications. Compare the line positions, mounting points and seal locations with the existing valve. A valve intended for one circuit cannot be assumed to fit another just because it has the same number of bolt holes.

Plan the required refrigerant-compatible seals before the system is opened. The applicable service procedure specifies how the connections are assembled and the refrigerant circuit is returned to service.

Frequently Asked Questions (FAQ)