Does idling with the AC on harm the engine?
2 Answers
Idling with the AC on for short periods does not harm the engine, but prolonged idling can be detrimental. Below are explanations regarding the impact of idling with the AC on the engine: 1. When idling with the AC on, the engine not only powers the AC but also maintains the normal operation of the power steering and brake booster pumps, which can affect the engine's lifespan to some extent. 2. Prolonged idling with the AC on can lead to increased carbon buildup in the engine and higher fuel consumption. Carbon buildup is highly harmful to the engine. If carbon deposits form in the combustion chamber, they can increase the compression ratio, causing engine knocking. Knocking is an abnormal combustion phenomenon within the engine.
I think running the AC while parked is a common practice in summer, but as someone who's driven for ten years, I have to say it can indeed harm the engine. The main reason is that operating the AC while the engine is idling significantly increases fuel consumption, burning an extra 1-2 liters of gasoline per hour—a pure waste of money. Even worse, if you do this for extended periods in hot weather, the engine is prone to overheating or accumulating more carbon deposits, affecting its performance stability. Once, I lost track of time waiting for a friend outside the car with the AC on for half an hour, and the hood became scalding hot. Later, a check revealed the battery was under heavy load and needed premature replacement. Now, I only do it briefly when absolutely necessary, like waiting for ten minutes or so, while ensuring proper ventilation to avoid the risk of poisoning in an enclosed garage. In the long run, this habit does more harm than good—cultivating the practice of turning off the engine can protect your beloved car.
