Does idling with the air conditioning on damage the car?
2 Answers
Idling with the air conditioning on does not damage the car. The main concern when idling with the air conditioning on is the water temperature, especially in older cars with mechanical fans. Mechanical fans are driven by the engine crankshaft, and at idle speed, the engine crankshaft rotates slower, causing the cooling fan to spin slower as well. Prolonged idling can lead to insufficient engine cooling, resulting in overheating. Below are the effects of idling with the air conditioning on: 1. Increased fuel consumption: The engine already consumes fuel while idling, and running the air conditioning requires the engine to power the compressor, which further increases fuel consumption; 2. Reduced battery life: The air conditioning blower is powered by the battery. At idle speed, the battery's charging efficiency is relatively low, and prolonged operation of the blower may lead to battery discharge, shortening its lifespan over time.
Idling the car with the air conditioning on won't immediately damage the vehicle, but it's best not to make it a habit. The engine bears minimal load at idle, and the AC compressor engagement may slightly drop the RPM. In the short term, this mainly results in higher fuel consumption and increased exhaust emissions. I've seen friends who drive like this year-round – their engines develop carbon deposits slightly faster, but regular maintenance like throttle body cleaning can address this. For short breaks on hot days, running the AC for about 10 minutes is perfectly safe. For durations exceeding half an hour, it's better to turn off the engine or switch to external air circulation to save fuel. Older vehicles require extra caution – monitor to prevent temperature spikes that could trigger overheating warnings. Occasional emergency use is fine, but making it a routine isn't beneficial for the car's longevity, as prolonged idling operates inefficiently and may gradually accumulate minor issues. Just pay regular attention to the coolant temperature gauge and oil condition during normal driving.
