Is it harmful to leave the car idling for 8 hours without turning it off?

[Keira]

It is harmful to leave the car idling for 8 hours without turning it off. If a car remains idling for more than an hour while parked, fuel consumption will increase even though the car is not moving. Below are the issues that can arise from prolonged idling: 1. Carbon buildup: Some impurities produced during fuel combustion cannot be completely expelled and adhere to corresponding components, forming black carbon deposits. When a vehicle remains idling for an extended period, the engine continuously operates at low RPM, making the pistons and valves more prone to carbon buildup. This can lead to unstable idling and other adverse effects on engine performance, and may even impact the engine's lifespan. 2. Impact on the vehicle's lifespan: Secondly, the three-way catalytic converter does not reach its optimal operating temperature, which affects its lifespan. Most vehicles are equipped with a three-way catalytic converter in the exhaust system. This is the most important external purification device for vehicle emissions, converting harmful gases like CO, HC, and NOx from exhaust into harmless carbon dioxide, water, and nitrogen through oxidation and reduction reactions.

[JamesonAnn]

When I first started driving, I also tried idling the engine for several hours without turning it off, mainly to keep the air conditioning running while waiting for someone. As a result, the engine noise became noticeably louder. During the subsequent maintenance, the mechanic found carbon buildup issues, and the engine oil had turned slightly black. Prolonged idling caused incomplete fuel combustion, leading to carbon particles accumulating on the cylinder walls, which not only damages the engine but also increases fuel consumption. For 8 hours, I imagine a significant amount of fuel was burned, and the engine temperature might have gotten too high, affecting the cooling system. The fan running continuously was also quite taxing. I think short periods occasionally are fine, but anything over half an hour should warrant turning off the engine—it saves fuel and protects the car. Now, I use a portable power supply with a fan instead of the air conditioning.

[Ingrid]

As a car enthusiast, I pay close attention to engine operating data. Idling for eight hours straight can cause oil temperature to rise excessively, leading to degraded lubricant performance and increased wear, especially between the cylinder walls and piston rings. Spark plugs are prone to carbon buildup and clogging, while hydrocarbon emissions in the exhaust surge, accelerating the aging of the catalytic converter. Prolonged idling can eventually result in ignition difficulties and reduced power output. Although idling is necessary for engine protection in extreme cold, it's generally not recommended to exceed two hours under normal conditions. I suggest keeping a Bluetooth OBD scanner in the car to check for trouble codes and perform timely cleaning maintenance.

[McAngelo]

I often think about the environmental impact of driving, and idling for eight hours straight is most harmful due to the pollution it emits. At idle, combustion efficiency is low, releasing large amounts of harmful gases and soot, which both pollutes the air and wastes resources. Cars aren't designed for prolonged idling; running the engine at low load can lead to carbon buildup, potentially triggering warning lights or causing the vehicle to fail emissions tests. While protecting the battery in extreme weather is understandable, modern cars come with start-stop systems, making it more sustainable to turn off the engine while waiting. We should minimize idling time for both environmental and safety reasons.