Is Leaving the Car Running for a Day Harmful?

[Edmund]

Leaving the car running for a day does not have a significant impact on the vehicle, but it does waste some fuel. Below is a detailed introduction to the potential harms of forgetting to turn off the engine: 1. Recommendation: It is advisable to develop the habit of turning off the engine immediately after parking, such as pressing the ignition button instinctively after shifting to P mode. If the engine is left running, the vehicle will remain in an idling state and continue to consume fuel, leading to higher fuel consumption compared to driving at an economical speed. 2. Other Harms: Leaving the engine running overnight will result in prolonged idling, which reduces the oil pump speed. At this point, the oil pressure is relatively low, making it difficult to effectively lubricate components such as the bearing bush. This can exacerbate wear and tear on the piston, connecting rod, and engine.

[AustinRose]

This is no small matter! My neighbor, Old Zhang, did this once and ended up calling a tow truck the very next day. Not only did he run out of gas, but the engine carbon buildup was severe—the mechanic found the spark plugs completely fouled when he opened it up. The most dangerous part was the exhaust backflow; his underground garage almost turned into a gas chamber. Now, Old Zhang keeps a sticky note in his car that says 'Turn off the engine.'

[GavinRose]

Over the years repairing cars, I've seen several vehicles break down like this. Running continuously for 24 hours can cause engine temperatures to soar to dangerous levels, turning the engine oil into an asphalt-like substance. Last week, I worked on a Ford where the piston rings were stuck due to carbon buildup—just cleaning the carbon cost 800. The exhaust pipe was glowing red, and the catalytic converter was basically ruined. Everyone, always check your dashboard when parking!

[Eden]

Let me do the math for you: A regular 2.0L car consumes 1.5 liters of fuel per hour at idle, which amounts to 36 liters in 24 hours. At ¥8.5 per liter for 95-octane gasoline, that's over ¥300 literally evaporating. And we haven't even factored in engine wear yet - the accumulated metal fatigue equals driving 2,000 kilometers, reducing critical component lifespan by at least three months.

[DeJoy]

Xiao Wang almost caused a disaster last time by forgetting to turn off the engine! His old Toyota kept running all night in the enclosed garage, filling the entire space with pungent exhaust fumes by morning. If the property management hadn't discovered it early, the carbon monoxide levels could have been fatal. Now he's put a glow-in-the-dark reminder sticker on the steering wheel and suggests friends who often park in garages install a remote monitoring app.

[VanIvan]

Let me break this down into three aspects: The most urgent is the safety hazard, as exhaust gas backflow can be fatal; the most costly is mechanical wear, as continuous operation can lead to piston ring deformation; and the most troublesome is subsequent repairs, which typically involve addressing both fuel line blockages and oxygen sensor malfunctions. It's advisable to develop the habit of pulling the door handle after locking the car and only leaving after hearing the locking sound.