Why is the car air conditioning very cold at night but has poor cooling during the day?
3 Answers
Car air conditioning being very cold at night but having poor cooling during the day is due to poor heat dissipation of the condenser. Below is relevant information about car air conditioning: 1. Air conditioning composition: Modern air conditioning systems consist of a refrigeration system, heating system, ventilation and air purification devices, and a control system. 2. Working principle: The functions of automatic air conditioning include automatic adjustment of in-car temperature and humidity, automatic control of air return and supply modes, as well as operation methods and air exchange volume control. The electronic control unit will operate the air conditioning system automatically based on the settings made by the driver or passengers via the buttons on the air conditioning display control panel. It will also adjust the air supply temperature and speed in a timely manner according to signals input from various sensors to maintain the optimal in-car air environment.
I encountered this issue with my old sedan and spent a long time figuring it out. During the day when the sun is scorching, the car gets extremely hot inside, and the air conditioning has to lower the cabin temperature from over 60 degrees, so the cooling effect naturally seems poor. At night when the temperature drops, it cools down much faster. Another key point is to check the AC condenser. During daytime traffic jams, the engine temperature is high, and the cooling fan is surrounded by hot air, which reduces the condenser's heat dissipation and affects cooling performance. Additionally, parking under trees in summer makes it easy for poplar fluff and insect remains to clog the radiator fins. In this case, just take it to a repair shop and use a high-pressure water gun to clean it. For cars over five years old, it's best to check the refrigerant pressure, as low refrigerant levels are also a common cause.
Last week, my neighbor Sister Wang also asked me about this issue. Her car, only two years old, was experiencing weak air conditioning performance during the day. The reason is simply that the daytime heat load is high, and the air conditioning system struggles to operate at full capacity, especially when idling at traffic lights where the engine RPM is low, and the compressor can't keep up. I advised her to check the cooling fan—some cars have fans that don't spin fast enough or have aging silicone fluid couplings, which can't provide adequate cooling in high temperatures. By the way, more and more car owners are applying sunshade films these days, but overly dark films can obstruct airflow to the condenser. Here's a handy tip: start the car five minutes early in the morning, open the windows to ventilate, and then turn on the AC—this can help reduce the cooling load during the day.
