Is it harmful to leave the car idling for three hours without turning it off?

[LeAustin]

Leaving the car idling for three hours without turning it off can have negative effects on the vehicle. Here are the specific impacts of prolonged idling: 1. Carbon buildup: When the engine runs at idle for a long time, the throttle opening is small, and the fuel injectors spray high-concentration fuel to keep the engine running. Therefore, idling itself is more likely to cause carbon buildup compared to high-speed driving. Prolonged idling can lead to severe carbon buildup in the engine, directly affecting the car's power and comfort. 2. Increased fuel consumption: The fuel consumption is high when the car is idling. Three minutes of idling is equivalent to the fuel consumption of driving one kilometer. 3. Shortened engine lifespan: When the engine is idling, the temperature and pressure in the cylinders are low, prolonging the fuel ignition time. Additionally, the cylinder sealing performance decreases, making it more prone to knocking sounds, which can shorten the engine's lifespan. 4. Damage to the catalytic converter: Prolonged idling causes the engine's air-fuel mixture to be too rich, reducing the oxygen content in the exhaust. The unburned mixture can ignite at the catalytic converter, potentially damaging it.