What are the symptoms of a clogged car AC expansion valve?

[StAlessandra]

When the car AC expansion valve is clogged, it can cause the air conditioning to produce cool air but with no airflow. The expansion valve is a crucial component of the car's cooling system, typically installed between the liquid receiver and the evaporator. The expansion valve allows medium-temperature, high-pressure liquid refrigerant to pass through and become low-temperature, low-pressure wet vapor for cooling purposes. It controls the valve flow based on temperature changes at the end of the evaporator, preventing insufficient utilization of the evaporator's surface area and knocking phenomena. The expansion valve has two main functions: throttling and controlling the refrigerant flow rate. Based on the balance method, expansion valves can be categorized into internal balance and external balance types. In a car's refrigeration system, the expansion valve is one of the four major components, alongside the compressor, condenser, and evaporator.