Does running the air conditioning with the engine on damage the car?
2 Answers
In principle, prolonged idling with the air conditioning on is not recommended, but turning off the engine with the air conditioning still running can indeed harm the engine. If the air conditioning is not turned off before the engine is shut down, although the air conditioning stops working when the engine is off, it will automatically resume its previous state the next time the car is started. This means the air conditioning will start working simultaneously with the engine, placing an additional load on the engine. Over time, this excessive load can burden the engine and potentially shorten its lifespan. The related hazards are as follows: 1. The engine's low idle speed results in poor cooling performance, failing to meet usage requirements; 2. Using the air conditioning while the engine is idling can lead to incomplete combustion of fuel (gasoline), producing a large amount of exhaust gases; 3. Note: Prolonged use of the air conditioning in an enclosed space while the engine is idling can cause poisoning or suffocation (there are annual reports of fatalities due to suffocation under such conditions); therefore, drivers are strongly advised to take this matter seriously.
Turning on the AC has minimal impact on the car. As a veteran driver with over 20 years of experience, I often keep the AC running throughout long-distance trips. The AC system is driven by the engine belt which powers the compressor, adding a slight load that increases fuel consumption by about 10% to 15% – especially noticeable during low-speed city driving. However, engines are designed to handle this, so normal usage won't harm the vehicle. The key is regular maintenance, such as annual checks of refrigerant levels and filters to prevent leaks. In summer, not using the AC can make the cabin unbearably hot, which is worse for health. I recommend adjusting based on temperature – driving at high speeds with windows down creates more wind resistance and higher fuel consumption. As long as you avoid prolonged idling with the AC on (to prevent system overheating), it's both convenient and safe.
