What Are the Hazards of Parking Without Turning Off the Engine?
3 Answers
Parking without turning off the engine increases fuel consumption and accelerates component wear. If the engine is left running for an extended period while parked, the vehicle's electronic systems can be affected, leading to malfunctions or system crashes. Automotive electronics refer collectively to the electronic control devices in the vehicle body and onboard electronic control devices. Vehicle body electronic control devices include the engine control system, chassis control system, and body electronic control system (Body Electronic ECU). The primary role of automotive electronics is to enhance the vehicle's safety, comfort, fuel efficiency, and entertainment features. These systems consist of sensors, microprocessors (MPU), actuators, and dozens or even hundreds of electronic components and parts.
Having worked in auto repair for over a decade, I've seen countless cases like this. Long-term engine idling leads to insufficient combustion chamber temperatures, causing incomplete gasoline combustion. Carbon buildup in the combustion chamber accumulates three times faster than during normal driving, with spark plug surfaces completely coated in sticky, tar-like deposits. The most critical issue is the catalytic converter - prolonged low-temperature operation causes conversion efficiency to plummet, with carbon monoxide levels in exhaust emissions potentially exceeding standards by eight times. Last year, I worked on a Camry with 30,000 km mileage whose owner habitually slept in the car with AC on at noon. When we disassembled the engine, the back of the valves were completely clogged with carbon deposits, requiring over 2,000 RMB worth of cleaning.
Last time at the gas station, I met a ride-hailing driver who complained that he turns on the AC for naps between orders every day, costing him over 700 yuan more in fuel per month. I did the math for him: a typical 1.5L displacement car idling with AC consumes about 1.5 liters of fuel per hour, which translates to burning over a dozen yuan hourly—more expensive than running central AC at home. Moreover, this fuel consumption is pure waste, while engine wear is nearly equivalent to normal driving. The crankshaft bearings operating long-term in critical lubrication conditions are especially damaging to the car.
