Does starting the vehicle with the air conditioning on harm the engine?
3 Answers
Starting the vehicle with the air conditioning on can harm the engine and accelerate component wear. Principle of air conditioning cooling: In the refrigeration system, the low-pressure vapor of the refrigerant is sucked in by the compressor and compressed into high-pressure vapor, which is then discharged to the condenser. The indoor air continuously circulates to lower the temperature. Principle of air conditioning heating: According to the type of heat source, the car heating system is mainly divided into two types: one uses engine coolant as the heat source, and the other uses fuel as the heat source. When the engine coolant temperature is high, the coolant flows through the heat exchanger in the heating system, exchanging heat with the air sent by the blower. The heated air is then blown into the car through various air outlets by the blower.
I always believe it's best to turn off the air conditioning when starting the car, especially during hot summer drives. This habit stems from my experience with an old sedan—once I forgot to turn off the AC before ignition, and the engine struggled noticeably during startup, draining the battery faster. Although modern cars are designed intelligently, with starting systems capable of handling extra loads, running the AC does increase the burden, making the starter motor and battery work harder. Over time, this could shorten the lifespan of these components, leading to unnecessary repair costs. That's why I've developed the habit of switching off the AC before ignition—vehicle startups feel much smoother now, avoiding potential issues. While it doesn't directly harm the engine, there's still a slight risk to the electrical system, making it worth paying attention to.
From a mechanical perspective, when starting the vehicle, the engine needs to rotate at full power. If the air conditioning is on, it adds extra load, especially the electrical consumption of the compressor. Modern vehicle systems can automatically adjust voltage, preventing immediate damage to the engine. However, older models may encounter issues such as battery voltage drops or accelerated starter motor wear. I recommend developing the good habit of turning off the air conditioning before starting to protect these auxiliary components. In the long run, this can reduce maintenance frequency and enhance vehicle durability. Neglecting such details during daily driving may lead to minor issues accumulating into major repair bills, which isn't cost-effective. Preventive measures are always a wise choice.
