Why does the car air conditioner not cool at idle but cools when running?

[Isaac]

Specific reasons why the air conditioner does not cool at idle but cools after driving: 1. Air conditioner compressor failure: The pressure between the air conditioner compressor and the expansion valve cannot reach 150Kpa to 200Kpa, causing the refrigerant inside the system to not circulate normally, resulting in the air conditioner not cooling at idle. 2. Expansion valve damage: The expansion valve cannot form high pressure, less than 150Kpa, causing the subsequent evaporator to not cool down, leading to no cooling at idle. 3. Loose or broken air conditioner belt: If the drive belt is too loose, it will slip, accelerating wear and preventing power transmission, resulting in insufficient power at idle, so it does not cool as much. 4. Dirty condenser: The condenser is used for heat exchange. If the surface is too dirty or has too much dust and dirt, it will not cool, naturally causing the air conditioner to not cool. 5. Radiator blockage: The external cooling system will not dissipate heat well, leading to poor heat dissipation at idle, resulting in no cooling at idle.