Does idling with the air conditioning on affect the engine?

[CeciliaMarie]

Idling with the air conditioning on does affect the car. When the engine operates at low speeds for extended periods, it is more prone to carbon buildup. Over time, this can lead to unstable idling and other issues that impact the engine's performance, as well as shorten its lifespan. Below is a detailed explanation of the effects of frequently idling with the air conditioning on: Effects: When the car is idling with the air conditioning on, the electrical reserves are limited, so the engine must work to maintain the air conditioning system. However, during idling, the combustion of gasoline is incomplete, releasing various pollutants, especially carbon monoxide, which can be more than ten times higher than during normal driving. Dangers: If the car is idling with the air conditioning on and the doors and windows are tightly closed for a long time, exhaust fumes can enter the enclosed cabin. If these fumes accumulate to a certain level, they can cause carbon monoxide poisoning.

[LaAlyssa]

Having driven for nearly two decades, I've seen many engines suffer from idling with the AC on. At idle, the engine runs at low RPM, but the AC compressor keeps working hard, significantly increasing engine load and causing fuel consumption to spike. Doing this for extended periods leads to incomplete combustion, which easily generates carbon deposits. When carbon clogs the pistons and valves, the car may start shaking and lose acceleration power. In severe cases, you’ll need to dismantle and clean the engine—costing both time and money. The battery also suffers—the AC fan consumes a lot of power, and at idle, the alternator can’t keep up, potentially draining the battery. If the car won’t start, you’re in trouble. Sleeping in the car with the AC on in summer is even more dangerous, as exhaust carbon monoxide could leak into the cabin. My advice: turn off the engine and open windows for ventilation when parked, or use a sunshade to cool the interior. During regular maintenance, check for carbon buildup and battery health—this extends engine life and saves you headaches and money.

[VonRafael]

As an average car owner, I'm particularly concerned about fuel costs. Idling with the AC on significantly impacts the engine - the engine runs idle while powering the AC, consuming much more fuel than normal driving. Idling for one hour can burn 1-2 liters of fuel, costing an extra 10-20 yuan at current fuel prices. If done daily, this adds hundreds to monthly fuel expenses. Carbon buildup is an even bigger headache - incomplete combustion leads to carbon deposits, reducing engine efficiency and potentially causing thousands in future repairs. Once when my car had unstable idling, inspection revealed severe carbon buildup, costing over 600 yuan to clean. The heavy electrical load also shortens battery life, with replacements costing hundreds. I recommend turning off the engine when parked, or just using the fan. Proper vehicle use protects the engine and saves considerable money.

[VanEmilio]

Having worked in an auto repair shop, I understand the hazards of running the AC at idle. When the engine idles, the RPM is low, and the AC compressor bears a heavy load, leading to incomplete combustion and easy carbon buildup. Excessive carbon deposits can cause the car to shake at idle, accelerate slowly, and in severe cases, require professional cleaning. The alternator's insufficient output may lead to excessive battery discharge, potentially causing failure. It's advisable to avoid prolonged idling with the AC on; instead, turn off the engine and ventilate when parked. Regularly check carbon buildup levels and perform simple maintenance, such as replacing the air filter, to prevent major issues.