Reasons for Car AC Not Cooling at Low Speeds
1 Answers
Car AC not cooling at low speeds is caused by insufficient pressure. Reason 1: Insufficient Freon: When the car is idling, especially when stopping at traffic lights or in traffic jams (lacking the cooling effect from driving wind speed), the low engine speed causes the compressor speed to also decrease. With insufficient Freon, its instant pressurization cannot reach the standard state, resulting in excessively low high pressure and suboptimal cooling performance. This can be resolved by adding some Freon, but it is important to use high-purity, environmentally friendly Freon. Reason 2: Compressor Pressure Leakage: This directly leads to severely low pressure at idle speed. In this case, the compressor needs to be replaced, which can be a significant expense. Reason 3: AC Cooling Fan Not Working: When the car is stationary, poor heat dissipation (lacking the cooling wind speed from driving) causes the pressure to become excessively high. The high-pressure sensor then forces the compressor to stop working, resulting in no cold air. In this situation, check the fuse, relay, and the fan itself to identify the faulty component and replace it. Reason 4: Expansion Valve Orifice Too Large: At idle speed, the low pressure becomes too high, significantly reducing the AC's cooling effect. This requires replacing the expansion valve and completely refilling the system with Freon.
