What does a AC expansion valve do?

The expansion valve removes pressure from the liquid refrigerant to allow expansion or change of state from a liquid to a vapor in the evaporator.

How to tell if an expansion valve is bad?

Symptoms of a Bad or Failing Expansion Valve (Orifice Tube) 1 AC system performing worse than usual and blowing warm air. 2 Frost on AC evaporator or coming from the vents. 3 AC compressor constantly running.

How does an expansion valve in an AC system work?

Many car makers now use automotive AC expansion valve in their AC systems. An expansion valve is simply a refrigerant metering device to control the rate of flow of refrigerant into the evaporator located in your dash. In the illustration below, you’ll see that low pressure gas flows out of the evaporator coil and through the expansion valve.

Can a bad expansion valve cause an AC system to overheat?

Too much refrigerant flow and the evaporator core will freeze over; too little and the evaporator core will overheat and compromise the efficiency of the AC system. The expansion valve meters refrigerant flow according to evaporator temperature and the load and cooling demand of the AC system.

Can a bad or failing expansion valve cause unmetered refrigerant?

Frost on AC evaporator or coming from the vents. Another symptom of a potential problem with the vehicle’s AC expansion valve or orifice tube is frost coming from the vehicle’s vents. If the AC evaporator or orifice tube malfunctions, it can cause refrigerant to flow unmetered through the vehicle’s AC system.

Where is the expansion valve on an AC unit?

The AC expansion valve is found within the air conditioning system of a vehicle. The purpose of the valve is to manage how much refrigerant liquid can flow throughout this system. Whenever there is an abundance of refrigerant, the core of the evaporator will get too cold and eventually freeze.