What can cause low refrigerant in a car?

Low refrigerant in a vehicle air conditioning system is almost always caused by a leak rather than natural consumption, since automotive AC systems are completely sealed loops. Common leak points include deteriorated rubber O-rings and seals at hose connections, corrosion or physical damage to the aluminum condenser coils located at the front of the vehicle from road debris impact, a cracked evaporator core inside the dashboard, or a failing shaft seal on the AC compressor itself. Over time, engine vibrations, temperature fluctuations, and aging metal or rubber components cause microscopic gaps to form, allowing pressurized refrigerant gas and lubricating oil to slowly seep out into the atmosphere. You can troubleshoot by inspecting component connections for oily residue. You can verify that the leak source is identified when professional UV dye testing or electronic sniffer tools pinpoint the exact rupture point.