Does Prolonged Idling Affect the Engine?
4 Answers
Prolonged idling does affect the engine. Here is a related introduction about car idling: 1. The function of car idling: Idling is an operating condition of a car, referring to the engine running in neutral gear. The engine speed during idling is called the idle speed. The idle speed can be adjusted by modifying the throttle opening size, among other methods. Idling means the engine is "exerting force without doing work." When the engine is running, if the accelerator pedal is completely released, the engine enters the idling state. 2. Causes of unstable idling: Direct causes refer to mechanical parts being dirty, worn, or incorrectly installed, leading to changes in cylinder power and resulting in an imbalance of power among cylinders, causing unstable engine idling. Indirect causes refer to abnormalities in the engine's electronic control system, leading to poor combustion of the air-fuel mixture, making it difficult to balance the power among cylinders and causing unstable engine idling.
I've encountered this issue before. A friend's car had severe engine carbon buildup from long periods of idling with the AC on. At idle, gasoline doesn't burn completely, leading to carbon deposits that can clog fuel injectors and cause fuel consumption to skyrocket. Moreover, engine oil can emulsify and deteriorate when left at low temperatures for too long. The mechanic said it's like soaking the engine in spoiled milk. The biggest problem is heat dissipation - I've seen cars where idling caused electric fan failure, with smoke coming from the engine bay. The solution was to turn off the engine every half hour for a break, or simply install a parking air conditioning system.
Long periods of idling can cause significant harm to a car. Firstly, fuel consumption is even higher than when driving, with data monitoring showing that idling for one hour can burn 1-3 liters of fuel. Low engine speed operation leads to insufficient combustion chamber temperature, resulting in incomplete gasoline combustion and the formation of gum deposits on the cylinder walls. There have also been many cases of ride-hailing drivers burning out their oxygen sensors due to this. Even more concerning is the exhaust emissions—tests on idling vehicles have shown carbon monoxide concentrations five times higher than during normal driving. Most newer cars now come equipped with automatic start-stop systems, which shut off the engine at red lights to avoid this issue.
Personal experience tells you: My old LaCrosse was ruined by long-term idling. In summer, waiting with the AC on for two hours caused the engine warning light to come on. Inspection revealed a clogged catalytic converter, and the repair cost was painfully expensive. The mechanic explained that low-temperature combustion causes carbon buildup in the catalyst, essentially a slow suicide for the exhaust treatment system. Now I've learned my lesson—I always turn off the engine if idling exceeds 15 minutes. Especially for turbocharged cars, be extra cautious: the turbo doesn't engage during idling, making it prone to carbon buildup and blade jamming. A smart tip is to use your phone for remote AC startup—far better than idling the engine.
