What are the symptoms of a clogged automotive expansion valve?
2 Answers
Automotive expansion valve clogging symptoms include: poor cooling performance, frost formation behind the valve, and abnormal compressor operation noise. The expansion valve is a crucial component in the refrigeration system, typically installed between the liquid receiver and the evaporator. It converts medium-temperature, high-pressure liquid refrigerant into low-temperature, low-pressure wet steam through throttling, enabling the refrigerant to absorb heat in the evaporator for cooling effect. The expansion valve consists of three main parts: valve body, temperature sensing bulb, and balance tube. Its features include: 1. Advanced dual-flow balanced port design; 2. Reduced system components by eliminating the need for separate check valves and solenoid valves; 3. Dynamic static superheat adjustment based on condensing pressure or pressure drop across the valve; 4. Stable superheat characteristics ensuring system operational stability.
When the air conditioning isn't cooling in summer and warm air comes out, I get anxious and suspect the expansion valve is clogged. The symptoms are quite obvious: sudden drop in cooling efficiency, the compressor frequently starts and stops, making strange buzzing noises; the air vent temperature is much higher than normal, blowing out warm air instead of cold; there might also be an unpleasant odor, like a musty smell spreading out. The expansion valve controls the refrigerant flow—once clogged, the pressure becomes abnormal, with the high-pressure side pipes scalding hot while the low-pressure side remains cool. I later realized this issue needs prompt attention, or the compressor might burn out, leading to more expensive repairs. Regular maintenance should include checking the pressure gauge to prevent clogging, avoiding breakdowns under the scorching sun.
