Does keeping the air conditioning on for a long time without turning off the engine affect the car?

[Alexa]

Keeping the air conditioning on without turning off the engine while parked does affect the car. Here is an introduction about keeping the air conditioning on without turning off the engine: 1. Impact: When the car is idling, the engine speed is relatively low. Turning on the air conditioning can cause incomplete combustion of fuel in the engine, which can easily lead to carbon deposits in the engine cylinders and on the throttle valve. Additionally, keeping the air conditioning on without turning off the engine will increase the car's fuel consumption. 2. Recommendation: In seasons when the air conditioning is used frequently, it is advisable to clean and disinfect the air conditioning ducts more often to improve the cooling effect. Develop a good habit of turning off the air conditioning before shutting down the engine.

[Leroy]

Having driven a taxi for over a decade, I know all too well the experience of running the AC without shutting off the engine in summer. With the AC compressor constantly running, the engine has to work extra hard, not only guzzling fuel but also accelerating carbon buildup—cleaning the throttle body weekly became routine. The incessant buzzing of the cooling fan wears out the motor bearings faster, necessitating replacements every two to three years. Not to mention, poor heat dissipation at idle has triggered the engine temperature warning light multiple times, forcing me to pull over in a panic. On long trips, I prefer to roll down the windows for ventilation, setting the AC no lower than 25°C, otherwise repair costs would double, eating up all my earnings.

[KimberlyRose]

I don't dare to turn off the engine when taking my kid out, as the child gets fussy when the car gets too hot. But last time, I kept the AC running for half an hour without turning off the engine in the underground garage, and a burnt smell came out of the vents. I immediately had a mechanic check it. He said the compressor kept grinding against the pulley, and the bearing grease might have been baked dry. Continuing like this could burn out the coils. Now I set a timer: after running the AC for twenty minutes, I must turn off the engine and let it rest for ten minutes. Battery voltage is also important; running the AC with the engine off can drain the battery, and a jump-start service costs 200 yuan each time.

[LeCamille]

Once during a camping trip, I left the air conditioning on all night in the wilderness. The next morning, the car shook like a tractor when starting. The auto repair shop said prolonged idling caused incomplete combustion, and carbon deposits in the exhaust pipe clogged the oxygen sensor—it took half a day of soaking with cleaner to clear it. Now you get it: idling with the AC on is like slow suicide for the engine, with piston ring wear three times worse than normal driving. My advice—when resting at highway service areas during long trips, just turn off the engine. Hanging a small fan by the window works way better than anything else.

[DiEllie]

As a mechanic, I've seen too many cases of premature AC system failures. Owners save a bit on startup fuel but pay dearly: prolonged clutch engagement overheats the compressor causing slippage, while refrigerant overpressure can burst cooling lines. Continuous four-hour radiator fan operation can fry the motor - just last month I replaced a GL8's entire assembly. The deadliest consequence is gasoline-diluted crankcase oil losing lubricity, drastically increasing cylinder scoring risks. Want savings? Install remote start for precooling instead!

[Matteo]

The most outrageous thing I've seen was a car with exhaust pipes glowing red, still running the AC while the coolant was nearly boiled dry. The principle is simple: AC cooling relies on the engine-driven compressor. At idle, the cooling fan spins slower, and the radiator temperature accumulates until it reaches 107°C before the major cooling cycle kicks in. Under such high-temperature conditions, engine oil thins out, rubber hoses age and crack, and the lifespan of the electric fan is halved. Now, whenever I take my family on road trips, I deliberately park in the shade, roll down the windows, and let the engine rest for twenty minutes before continuing—it's much safer that way.