Is It Good for the Car to Idle with the Air Conditioning On?

[DiStephanie]

Idling with the air conditioning on has a slight impact on the car's engine and can lead to carbon buildup. Other effects and the working principle of the air conditioning system are as follows: Effects: It can cause carbon buildup at the exhaust pipe outlet and increase fuel consumption. Working Principle: The car's air conditioning system uses residual heat from the coolant for heating and relies on the phase change of refrigerant for cooling. The car's air conditioning refrigeration system consists of a compressor, condenser, receiver-drier, expansion valve, evaporator, and blower. These components are connected by copper pipes and high-pressure rubber hoses to form a sealed system. When the refrigeration system operates, the refrigerant circulates through this sealed system in different states.

[Cupid]

I've been driving a taxi for fifteen years and often see passengers idling their cars with the AC on while waiting. To be honest, this is quite damaging to the car. When the engine idles, incomplete combustion can easily lead to carbon buildup, and over time, you'll notice unexplained increases in fuel consumption. The AC compressor running continuously accelerates wear and tear, and if the battery is old, it can easily drain. The most dangerous part is that doing this in an enclosed garage can lead to carbon monoxide poisoning due to exhaust buildup. My advice is to shift to neutral, crack the window slightly, and don’t exceed 20 minutes if you need to run the AC while waiting.

[MacEzra]

Once I was queuing at a seaside scenic spot, and the guy in front of me kept the air conditioning on while sleeping for two hours. Eventually, his car started smoking and broke down! Running the engine at low load for extended periods while idling with the AC on prevents the oil temperature from rising properly, which actually accelerates internal wear. My mechanic friend told me that this practice can also deplete the lubricating oil in the AC lines, and repairing a damaged compressor can cost several thousand yuan. Now when it's hot, I'd rather roll down the windows or find some shade to rest in.

[VanJourney]

Last time when I picked up my child from school, I noticed parents idling their cars with the AC on in the parking lot. After researching at home, I found that idling with the AC consumes up to 2 liters of fuel per hour, and the power consumption is equivalent to 30 smartphone fast chargers. This practice is not only costly and harmful to the vehicle but also results in severely excessive exhaust emissions. I've since developed the habit of turning off the engine if the wait exceeds ten minutes—it's both eco-friendly and protects the engine and turbocharger components.

[JaydenMarie]

As a woman driver, my top concerns are safety and economy. I used to think it was normal to idle the car with the AC on while waiting in summer, but later learned that idling with the AC can cause fuel dilution, where gasoline mixes into the engine oil, reducing lubrication. Moreover, prolonged lack of ventilation can lead to inhaling harmful substances released from the car's plastics. Now, I always carry a small fan or an ice seat cushion, and if it gets too hot, I just start the engine for ten minutes before turning it off. Isn't it great to save on battery maintenance costs and treat myself to milk tea instead?

[DeCaden]

When I first got my new car, I also loved to idle with the AC on and take naps. During a maintenance check, the technician showed me the cylinder condition with an endoscope: the black carbon deposits were shocking! They explained that low-speed idling causes insufficient cylinder temperature, leading to incomplete fuel combustion. Even worse, the AC evaporator box stays damp for long periods, breeding mold, which causes unpleasant odors when the AC is turned on. Now, I use my phone to remotely start the AC, let the car ventilate for five minutes before turning it off and getting in—keeping it cool while protecting my beloved car.