What Causes Slow Cooling of Car Air Conditioning After Prolonged Sun Exposure?

[MacChristopher]

Car air conditioning cools slowly after prolonged sun exposure due to the compressor protection device tripping. Causes and solutions for excessively high pressure and overheating: 1. Excessive refrigerant: Appropriately reduce the refrigerant amount. 2. Poor heat dissipation: Check for dirt on condenser pipes and clean the condenser. 3. Blocked pipeline system: Refer to pressure gauge readings for diagnosis and resolution, then reprocess the system. 4. Dust accumulation on evaporator or filter: Reduced airflow causes system pressure and temperature imbalance; clean the evaporator or filter. 5. Possible refrigerant deficiency: When refrigerant is insufficient, compressor exhaust temperature becomes excessively hot, causing the overload protection switch to trip.

[LorenzoLynn]

I've experienced the slow cooling of car air conditioning after being exposed to the sun many times. As a daily commuter driving to and from work, I've noticed that when the car is parked under the scorching sun, the interior temperature rises extremely high, and the cooling effect of the air conditioner is significantly reduced once turned on. The main issue lies in the air conditioning system's struggle against the overheated environment—after being exposed to the sun, too much heat accumulates inside the car, the efficiency of the radiator decreases, leading to a slower cooling cycle. Additionally, the refrigerant pressure may be unstable or insufficient, requiring the compressor to take longer to adjust its state. Insufficient fan cooling can also be a hindrance. I usually open the windows for ventilation for two to three minutes to let the hot air out, then turn on the air conditioner in low-speed internal circulation mode, which works much better. Regularly cleaning the air conditioning filter and checking the fan speed can help avoid similar situations.

[ColeDella]

I've been driving my old car for over a decade, and slow air conditioning cooling after sun exposure is extremely common. There are many reasons: the soaring interior temperature makes it difficult for the AC to dissipate heat, the condenser can easily get clogged with dust and fail to cool; if the refrigerant leaks or ages, cooling efficiency drops significantly; the compressor is prone to overheating in high temperatures. My usual practice is to park in the shade whenever possible and use sunshades to reduce direct exposure. After starting the car, don't rush to close the windows—first, turn on the external circulation to ventilate for a few minutes before switching to internal circulation for cooling. If it happens frequently, it's necessary to check if there's an issue with the cooling system—don't wait for a minor problem to become a major one.

[AlessandraLynn]

As an amateur car enthusiast who loves tinkering with vehicles, I've pondered the reasons why car air conditioning cools slowly after being exposed to intense sunlight. The core issue lies in thermal load imbalance—prolonged exposure causes significant heat buildup inside the car, while the AC condenser suffers additional high-temperature effects, slowing refrigerant flow. If the fan lacks sufficient power or has dirty blades, the situation worsens. I recommend simple checks like ensuring the condenser fins are unobstructed and the filter is clean. After sun exposure, running the AC at high fan speed in external circulation mode for a few minutes helps expel hot air and accelerates the cooling process. These minor adjustments can significantly improve cooling speed.