Why does the car get hot when the air conditioning is on and the car stops in summer?
3 Answers
Here are several reasons why the air conditioning cools the car while driving but it gets hot when parked: 1. Poor heat dissipation in the air conditioning and engine cooling system: High temperatures when parked cause the air conditioning to perform poorly. When driving, the enhanced heat dissipation capacity allows the air conditioning to function normally. Common issues include a dirty radiator condenser. Over time, the condenser surface accumulates a lot of dirt, which needs to be cleaned regularly to maintain the air conditioning in good condition. Another issue is a malfunctioning cooling fan. If the fan does not turn on when the air conditioning is started at idle, the fan may be broken and needs to be replaced with a new electronic fan. 2. Poor performance of the air conditioning system: For example, Freon leakage or insufficient Freon added during replacement can prevent the air conditioning from achieving good cooling effects during operation.
I totally feel you on this issue! The AC cools fine while driving, but once you stop at a red light, it feels like sweating buckets—mainly due to poor heat dissipation. When moving, natural airflow helps cool the radiator, but when parked, you're relying solely on the small fan. In summer heat, radiator efficiency drops significantly, and the AC compressor starts slacking off too. Plus, at idle, the engine's lower power output reduces cooling effectiveness. My advice: switch to recirculation mode at red lights, turn on the AC five minutes early to precool, and check if the radiator grille is clogged with willow catkins or bugs.
As an experienced driver, I think this issue depends on two factors. First, when the engine is idling at low RPM, it doesn't provide enough power to drive the air conditioning compressor. Second, the radiator relies on airflow while driving for cooling, and the electric fan alone can't handle the heat dissipation when parked. This becomes especially noticeable in cars that are a few years old, where radiator dust buildup or insufficient refrigerant makes it worse. Just last week, my neighbor had to spend 800 yuan to fix a clogged radiator. Remember to clean the front grille and check refrigerant pressure during maintenance - that money is well spent!
