How Long Can a Car Idle?
2 Answers
Normally, the idle speed ranges between 700-800 RPM. If it's too low, the engine may vibrate easily, while a higher idle speed leads to increased fuel consumption. Below is more relevant information about car idling: 1. Normal Idle: When the vehicle is in a parked state and the engine is started, the minimum stable operating speed of the engine is referred to as parking idle. 2. Driving Idle: During gear shifting, if the accelerator pedal is not pressed or is released while driving, maintaining the minimum throttle opening, the engine speed at this state, which is consistent with the parking idle, is called driving idle. 3. Precautions: Unstable car idling is mainly manifested by fluctuations in the tachometer needle during idling, with unstable pointing, moving up and down. Unstable idling is often accompanied by idling vibrations. Under normal circumstances, the engine idle speed can be determined, with the specific level depending on the tuning of the particular vehicle model. Generally, a higher idle speed results in relatively higher fuel consumption, but an idle speed that's too low may cause the engine to vibrate or even stall.
As a veteran driver who frequently takes long trips, I've encountered several instances of prolonged idling. Car idling—when the engine keeps running while in Park or Neutral—can theoretically last for hours, but you should never do this. Once, I foolishly idled for half an hour waiting for a friend, and the engine bay became unbearably hot, fuel consumption soared to over one liter per hour, and my wallet took a serious hit. More importantly, it accelerates carbon buildup, clogging spark plugs and cylinders, leading to ignition issues. My rule now: never idle for more than five minutes when parked; if waiting longer, just turn off the engine. In winter, warming up the car doesn’t take long—just a few dozen seconds for the oil to circulate. By the way, prolonged idling also harms the exhaust system, and repairs can be costly. In short, protecting the engine is key—keeping idle times short saves both hassle and money.
