What Are the Causes of High Pressure in Car Air Conditioning?
3 Answers
Introduction to the causes of high pressure in car air conditioning: Excessive refrigerant: Release part of the refrigerant or completely discharge and refill it; Excessive compressor oil: Discharge all the refrigerant, use a machine to extract the excess compressor oil, and then refill the refrigerant; Poor heat dissipation in the condenser: Clean the surface dirt and pipes of the condenser, and check the cooling fan to see if it operates at high speed; Expansion valve or expansion tube opening too small: Replace the expansion valve or expansion tube, thoroughly clean the air conditioning pipes, and replace the dryer if present. Car air conditioning generally includes refrigeration devices, heating devices, and ventilation devices.
My car also had the issue of high AC pressure, which made the long drive unbearably hot. It turned out the refrigerant was overfilled. The mechanic explained that too much refrigerant in the system causes pressure to skyrocket, just like a balloon bursting if overinflated. If the condenser is clogged with dust and can't dissipate heat properly, or if the fan isn't spinning, it can also lead to high pressure—especially noticeable in hot weather. Another possibility is a stuck expansion valve or air infiltration in the lines. These small issues can snowball into major trouble. Excessively high pressure not only reduces cooling efficiency but also risks damaging the compressor, leading to costly repairs. Now, before summer hits, I always clean the front grille and check the fan’s operation to prevent such problems—saving hassle, money, and ensuring safety.
Last month, the air conditioning in my beloved car suddenly stopped cooling, and the high-pressure warning light on the dashboard lit up, which gave me a scare. I immediately drove to the shop for inspection. The technician said that high pressure is often caused by the condenser being clogged with debris, leading to poor heat dissipation and obstructed refrigerant circulation. He mentioned that an excessive amount of refrigerant beyond the standard can also cause excessive pressure, often due to people haphazardly adding refrigerant themselves. Fan failure or slow rotation becomes more pronounced in high temperatures, especially during city traffic jams. One thing I learned is that if the expansion valve fails and cannot regulate the flow, the system pressure becomes imbalanced. Such faults, if not addressed promptly, may shorten the lifespan of the air conditioning system and even affect the engine compartment temperature. Since then, I’ve made it a habit to pay special attention to cleaning dust off the condenser surface during regular car washes.
