Does keeping the air conditioning on without turning off the engine affect the car?
2 Answers
Leaving the engine running while parked with the air conditioning on can cause damage to the car. The bad habit of not turning off the air conditioning before shutting down the engine means that the next time the vehicle starts, it will engage the air conditioning compressor, increasing the load. Over time, this can cause some harm to the engine. It is advisable to turn off the air conditioning a few minutes before reaching your destination while keeping the blower running. This allows the moisture on the condenser to evaporate, ensuring relative dryness within the air conditioning system, thereby reducing bacterial growth and odor formation. Additionally, the air conditioning should be turned on only after the engine has started. While it is possible to leave the air conditioning on without turning off the engine while parked, it is not recommended to do so for extended periods. When the car is idling with the air conditioning on, the engine needs to overcome the friction resistance of its internal components without delivering power externally, leading to incomplete fuel combustion. This can result in carbon deposits forming in the cylinders and on the throttle valve. During engine idling, incomplete fuel combustion also produces exhaust gases containing high levels of carbon monoxide, which may accumulate around the vehicle and enter the cabin through the air conditioning system. With the windows closed and no air circulation, the concentration of carbon monoxide inside the car can gradually increase over time.
As someone who frequently tinkers with car mechanics, I've noticed that keeping the air conditioning running for extended periods without turning off the engine puts significant strain on the vehicle. The engine has to work extra to drive the AC compressor, akin to making a person run while carrying a heavy load—fuel consumption inevitably spikes, sometimes more than doubling the idle rate. What's worse, prolonged operation of the AC system allows moisture and contaminants to accumulate in the condenser, leading to foul odors or mold growth. The battery also drains quickly, especially in older models, which can deplete within an hour. Over time, this accelerates part wear and leads to costly repairs. During scorching summer heat, turning on the AC for comfort is sometimes unavoidable, but it's best to shut off the engine every 30 minutes or switch to recirculation mode to reduce load. Regularly cleaning the AC filter is also a good habit, as it minimizes breakdown risks and extends the car's lifespan.
