What Causes Car AC to Not Cool at High Speed but Cool at Low Speed?

[SanArianna]

When a car's air conditioning fails to cool at high speeds, there are two main reasons. The details are as follows: 1. Insufficient Refrigerant: A lack or shortage of refrigerant in the car's AC system can cause it to not cool properly. The primary cause of insufficient refrigerant is usually minor leaks in the system. If there is not enough refrigerant in the AC system, the amount of refrigerant sprayed into the evaporator from the expansion valve will also decrease. Consequently, the heat absorbed during the evaporation of the refrigerant in the evaporator will be reduced, leading to a drop in cooling capacity. If the refrigerant is insufficient, it should be replenished. 2. Moisture Intrusion: The presence of moisture in the car's AC refrigeration system can result in insufficient cooling or no cooling at all. If the lack of cooling is due to moisture in the refrigeration system, the desiccant or dryer in the car's AC should be replaced. At the same time, the system should be evacuated and recharged with an appropriate amount of new refrigerant.