How Long Can a Car Idle and What Happens During Idling?

Do you ever think about how long can a car idle when waiting at a traffic sign or warming it up on a chilly morning? Idling is the state in which the engine runs but the vehicle is not in motion. 

You sometimes need to idle the car, especially when you have not used it for a long time. The engine gets jammed when left idle for weeks or months.

Idling for a minute every week will keep the engine components and mechanism in shape. Diesel-run vehicles also need a few minutes of idling for clearing the exhaust of their fumes.

So how long can a car run idle in this condition? Does doing so burn too much fuel?

What Does Idling Mean And Why Is It Sometimes Necessary?

Idling is what happens when you let your car keep running without moving. For most vehicles that run on the street, there is nothing you can do other than idle your car when you are stuck in traffic. 

Especially for someone who uses diesel engines, not letting the car idle can be considered a borderline criminal offense. Idling a diesel engine allows the exhaust fumes to clear.

How Long Can A Car Idle?

A vehicle actually consumes only a small amount of fuel when idling. So, how long can a car idle? The answer is – indefinitely. However, it depends on a few conditions. The idling will last forever until:

  • Something breaks. Keeping the car standstill with the engine on for a very long time can put stress on some components and break the fan belt or thermostat.
  • The car runs out of gas. After that, the engine will stop and the vehicle will cool down to the ambient temperature.
idle car
A vehicle actually consumes only a small amount of fuel when idling. (Photo: VEHQ)

It is the same when you park your car in the parking lot. Many people ask “how long can I leave my car running while parked”. 

The time of cars idling your vehicle depends on how much gas you have in the gas tank and whether there is any part of your car broken.

If you are going to leave your car in an idling state for months, don’t forget to disconnect the battery before leaving. Otherwise, the battery will be drained out and need to be recharged.

When you need to start the engine, just connect the battery and the vehicle will run without any issue.

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How Long Can a Car Idle: The Precautions You Should Take

You already know how long can a car idle, but there are some precautions that you have to keep in mind. They are: 

  • Keep the car maintained and serviced on a regular basis.
  • Disconnect the battery. Keep it in a dry place with its terminals oiled.
  • Spray oil on the spark plug sockets after removing them. Then, put them back into their slots. It will prevent the forming of rust on the cylinder head.
  • To prevent rolling, put the car in first gear and use wood or similar material on four wheels. Don’t make the mistake of engaging the parking brake.

How Long Should A Car Idle?

There is a clear answer for how long can a car idle, but how long should a car idle? It is believed that you should keep cars idling for 30 seconds to a minute. So when you are stuck in traffic or waiting for the traffic light. 

Let’s check if you have to wait more than 1 minute, and turn off the engine. Leaving it running for longer than 1 minute would bring additional pollution to the air. 

Or if you turn off the engine even if you just need to wait for 10 – 20 seconds, it consumes more fuel than letting your car idle. 

When you park a car, after packing, usually most of us will take some minutes to relax, and get prepared before going out of the car. It may take a few minutes, but it will take time for us. No one wants to come out without being well prepared. 

But you should not idle the car for too long, it will be dangerous for you and your passenger. If your car is idle and the air conditioner is on, you risk carbon monoxide poisoning. 

What Happens When a Vehicle Idles for a Long Time?

You can leave your car idling for a few minutes although modern vehicles don’t need idling to be warmed up. 

The models running with an automatic transmission also don’t need it. You can just rev up the engine and drive even if it’s a cold morning.

how long can you idle a car
You can leave your car idling for a few minutes. (Photo: Rewire Security)

So is it bad to let your car idle? However, you should not leave the vehicle in that state for a long time (more than 30 minutes) because it will burn fuel and cause damage to the environment by releasing exhaust fumes.

FAQs on Idling A Car

  1. Is idling bad for your car?

Idling too much can damage your engine’s cylinders, spark plugs, and exhaust systems, among other parts. Fuel does not completely burn when an engine is idle since the engine is not working at peak temperature.

  1. How long can you keep your car running while parked?

Is it bad to keep car running while parked? The answer is yes, it may harm. Never let the engine idle while parked for longer than 30 seconds, according to the EPA. 

Realistically, 30 seconds isn’t long enough to harm something, but several extended idles can. Overheating might result from running the engine for a few hours to a day.

  1. Can a car idle on a full tank for how long?

The limit can be 3 hours of idle time on a full tank. Write down your calculation for the number of hours your particular car can idle on a full tank. The next step is to modify that number in accordance with the petrol remaining in your tank.

Pic / alt: engine idle

  1. Is it better to idle or turn car off?

Turning the car off can help you save gas and cut down on carbon dioxide emissions, unless you drive a classic automobile with a carburetor. Idling is believed by many drivers to burn less gasoline than resuming. 

However, some studies have shown that drivers may save gasoline and cut pollutants by shutting down at pauses that last no more than 10 seconds.

  1. How long can I idle my car with AC on?

You may leave your car’s AC on for as long as you’d like as long as the engine is running and you have enough gasoline. Since the compressor needs engine power to operate, running the AC with the engine off won’t result in cold air either.

Check out this video from Engineering Explained to get more information on how much fuel does engine idling use!

Sum Up

We hope that this information will help you have broadened knowledge about how long can a car idle and what happens during idling. If you have any questions about car idling, don’t hesitate to leave us a comment below!

At the same time, do not forget to follow our maintenance tips for better understanding of your car and repair when it is needed.