What Are the Reasons Why a Car's Air Conditioning Sometimes Suddenly Stops Cooling?
4 Answers
Car air conditioning sometimes suddenly stops cooling due to the following reasons: 1. Insufficient or too little refrigerant; 2. Excessive refrigerant; 3. Loose drive belt of the car's air conditioning compressor; 4. Excessive impurities in substandard refrigerant and refrigeration oil; 5. Moisture infiltration into the refrigeration system. The usage method of the air conditioning is: 1. Turn on the AC switch; 2. Adjust the air outlet selection knob—direct the air outlet upward when cooling and downward when heating; 3. Adjust the fan speed switch; 4. Adjust the air recirculation conversion knob; 5. Adjust the temperature control knob. The maintenance methods for the air conditioning are: 1. Clean the air conditioning vents promptly; 2. Maintain the air conditioning condenser in a timely manner; 3. Clean or replace the air conditioning filter element promptly.
As a technician who frequently works on cars in repair shops, I've encountered many cases where the air conditioning suddenly stops cooling. The most common issue is refrigerant leakage, as aging pipelines are prone to cracks or poor sealing at joints leading to gas escape. If the compressor's clutch sticks or fails, it may click during startup but won't turn; loose belts also fail to transmit power. A condenser clogged with debris causes poor heat dissipation, or an electric fan not spinning can trigger a protective system shutdown. Electrical problems like blown fuses or stuck relays may cut power without response during overload. A dirty air filter reducing airflow might also falsely trigger abnormalities. In such cases, don't push through—safely pull over to inspect basic components and seek professional help to fix leaks before the system worsens.
Last summer during a road trip, my car's air conditioning suddenly went haywire and stopped cooling. Later, I found out the problem was mostly due to daily neglect. The filter was clogged with dust and debris, preventing cold air from blowing out; the battery terminals were loose, causing voltage instability; the compressor belt was old and slack, squealing and stalling when I stepped hard on the gas. Sometimes it was the expansion valve blocked by condensed water droplets, causing the refrigerant to get stuck; other times, the electronic control board had faulty sensors, misreading overheating or low pressure and shutting down. It's advisable to regularly clean the filter to ensure it's unobstructed and start the car to listen if the compressor sounds normal. Regular maintenance and part replacements can extend its lifespan—don't wait until a breakdown on the road leaves you calling for a tow truck.
The air conditioning system is a sophisticated electronic network, and sudden malfunctions often occur due to intelligent control errors. Pressure sensor failures may falsely report low pressure and halt output; damp temperature probes can short-circuit and mislead the computer into shutting down; ECU chips may overheat, melt, and stop functioning. The purity of refrigerant and the condition of the compressor rely on data calibration, and loose or interfered data lines can cause intermittent faults. Troubleshooting requires using a multimeter to test circuit connectivity and address weak points.
