Should the Air Conditioning Be Turned Off Before Shutting Down the Engine?

[DiArya]

It is essential to turn off the air conditioning first. Below is an introduction to car air conditioning: Car Air Conditioning Introduction: Car air conditioning consists of a compressor, condenser, throttle element, evaporator, fan, and necessary control components, forming an air conditioning system that regulates the temperature and humidity inside the vehicle, providing a comfortable environment for the driver. Working Principle: When the compressor operates, it inhales low-temperature and low-pressure gaseous refrigerant from the evaporator. After compression, the temperature and pressure of the refrigerant increase, and it is sent to the condenser. Inside the condenser, the high-temperature and high-pressure gaseous refrigerant transfers heat to the outside air passing through the condenser, causing it to liquefy and turn into a liquid. When the liquid refrigerant flows through the throttle device, its temperature and pressure decrease, and it enters the evaporator. Inside the evaporator, the low-temperature and low-pressure liquid refrigerant absorbs heat from the air inside the vehicle passing through the evaporator, causing it to evaporate and turn into a gas. The gas is then inhaled by the compressor for the next cycle.

[ORonan]

As a veteran driver with over 20 years of experience, I always recommend turning off the air conditioning before shutting down the engine. The AC compressor relies on engine operation. If you don't turn it off before stopping the engine, the starter will have to handle the AC load during the next startup, which puts significant strain on the battery and may lead to difficult starts or premature battery failure. During hot summers when the AC is set to high, the starting pressure is even greater. I've seen many car owners neglect this and end up with drained batteries or damaged starting systems. Developing this simple habit can extend the life of both your starter and battery, making startups smoother. There's an added benefit - with reduced engine load, you might even save a tiny bit of fuel. I always turn off the AC before parking, and my long-running vehicle has fewer issues. Paying attention to these details is always better than spending big on repairs later.

[McViolet]

I've been driving for several years, and I always turn off the air conditioning before shutting down the engine. It's a little trick I learned from a friend. When you turn off the car directly with the air conditioning on, residual pressure remains in the system, which might strain the engine during the next startup. Once, I forgot to turn it off in a parking lot, and the car shook a few times before starting. Since then, I've made it a habit to check. This action only takes a few seconds but can prevent unexpected issues. A smooth engine start also gives me peace of mind. Protecting car components during daily use is crucial—saving a bit on battery or repair costs isn't worth the risk. In short, an extra check before acting never hurts.

[LeDaniela]

For driving safety, I agree with turning off the air conditioning before shutting down the engine. If the air conditioning is left on when the engine is turned off, the engine load will increase during the next startup, potentially causing startup failure, especially in low-temperature or humid environments where the risk is higher. Once the engine fails to start, you might be stranded on the roadside, leading to accidents or emergencies. Developing this habit can prevent unexpected incidents and reduce the likelihood of vehicle malfunctions. I never joke about this—car electrical systems are quite sensitive, so extra caution is always beneficial.