What Causes High Temperatures Inside the Car?

[DeNova]

Here are the specific reasons for high temperatures inside the car: 1. Insufficient coolant: Leakage or lack of coolant can cause the engine water temperature to rise excessively, leading to overheating. The engine's heat dissipation primarily relies on the continuous circulation of coolant, which carries away the internal heat of the engine and dissipates it through the radiator. 2. Cooling fan malfunction: Damage or failure of the electric fan can cause the coolant temperature to rise and overheat. 3. Water pump malfunction: If the water pump operates inefficiently, or if the impeller falls off or slips, it can slow down or even stop the circulation of coolant, leading to excessively high engine temperatures. Additionally, aging seals in the water pump can cause leaks. 4. Thermostat malfunction: The thermostat automatically adjusts the amount of coolant entering the radiator based on temperature, altering the circulation range to regulate the cooling system's heat dissipation capacity. If the thermostat fails, the car's cooling system may not perform a full circulation, causing the water temperature to rise.

[McArthur]

I drive an old car, and in the summer, opening the door often feels like stepping into an oven. The main reasons are, first, direct sunlight on the windows absorbs heat, especially on the windshield where temperatures soar. Also, the air conditioning system isn't powerful enough—for example, my car once had a refrigerant leak, blowing out only hot air. A clogged filter can cause the same issue; the fan runs loudly but no cool air comes out. Using a sunshade when parked helps a bit. I've tried covering the roof with a reflective blanket, which lowers the temperature by several degrees. Another issue is aging door seals, allowing hot air to seep in, so regular checks or replacements are necessary. Engine overheating can also affect AC performance, though this is less common. Regular cleaning of the AC system is very helpful to avoid sweating buckets when heading out.