hot engine

How Long Does It Take for a Car to Cool Down

There are two specific heat-related problems to consider when driving cars. One is related to the efficiency of your engine and its components and the other is common physics.

First, you may wonder how long your car’s engine may take to cool down, and second, you may actually be wondering how long the interior of your car will take to cool down, especially critical on hot days and especially if you don’t have air conditioning.

These two problems are serious because an overheating engine can cause damage to the car and will almost certainly affect performance or cause the car to break down. An overheated interior is not merely uncomfortable but can be very dangerous, so understanding how your car cools down is very important.

So let’s take a deeper look at both of these cases.

Table of Contents

Why Is It Important To Know How Long Your Engine Takes to Cool Down?

Have you ever noticed that your engine is getting too hot? This might cause you to worry, and so it should as overheating engines can cause damage to your car and this might also be a sign of other problems in your car such as the cooling system.

If you do notice that your dashboard engine temperature gauge is showing a high reading then you might be tempted to stop your car and wait for it to cool down before driving off again. How long will this take?

Yet another reason why you need to know how long it will take for your car to cool down is that it is necessary to check the level of water in your car’s cooling system from time to time and this must be done when the car has cooled down.

If you open the cooling system filling cap when the engine is hot air and water can shoot out and this is obviously dangerous! You must only open up the cap to top up the cooling system with water when it has reached a safe temperature. How long does this take to reach for a car that you have been driving?

On the other hand you might just be curious to know the answer, so let’s get down to it.

How Long Does It Take for a Car to Cool Down
Source: Gandgautorepair

How Long Does It Take for a Car to Cool Down

Car engines are not designed to operate continuously for more than 10 minutes or so without cooling down. This is why engines have cooling systems which constantly try to remove as much heat as possible from a running engine so that it keeps a constant temperature. If it overheats performance will suffer.

There are many factors that can affect how long it takes for an engine to cool down. Outside air temperature is the most important factor in determining how quickly an engine will cool, but if the vehicle is stopped in traffic or on a hill, it will take longer because the air cannot move around the engine. This might cause a temporary increase in the temperature of your car’s engine.

For different types of engines, there is no one answer that can be applied across all models. For example, a turbocharged engine will have different cooling properties than a hybrid electric model or a standard gas-powered drivetrain system.

The length of time it takes for an engine to cool down is largely dependent on how hard it has been worked – if an engine has been idle or only doing light work it will take longer to cool.

The higher the temperature of an engine, the more quickly it will need to be allowed to cool before being restarted.

According to, the average running temperature for a car’s engine is 195 to 220 degrees Fahrenheit. So let’s assume you think you need to fill up the cooling system with more water, how long should you wait until the engine has cooled enough? One thing you can’t do is determine if the engine has cooled by just touching the coolant filling cap, it may feel OK but the engine may still be too warm.

I have seen many recommend waiting for 30 minutes to let the car cool down, but is this figure reliable?

In fact, according to Science Net Links, a car that has been driven and reached normal operating temperature may take as long as 8 to 12 hours to completely cool down to a cold engine. This is because there are so many internal components that may stay warm for hours as they are hidden inside the engine.

In other words, the answer to the question of how long does a car take to cool down is not easy to answer because it depends on what you mean. Completely cold or safe temperature to open and refill the cooling system. two completely different things.

There are varying answers to be found by car owners discussing this question on Quora. David Brown, a former Trailer Mechanic says that in the summer it can take an hour for a car to cool to such a point that it can be safely worked on.

He adds that in cold winter temperatures such cooling can take place in ten minutes or so. The reason for this huge difference is the difference in temperature between the outside temperature and that of the engine. The greater the difference, the quicker the engine will cool.

In the same discussion, another person confirms that it takes about an hour after stopping a car until the engine is cool enough to touch it safely.

A Car Parts Sales Rep in the discussion on Quora goes on to mention that some mechanics need to diagnose the performance of a car at cold starting temperatures, which means that the entire engine and all its parts need to cool down to ambient temperature. This, he states, requires an overnight cool down, which seems to agree with the figure we gave above (8 to 12 hours).

Other factors that will affect how slowly or quickly a car’s engine will take to cool down besides ambient temperature include:

  • whether the car is left outside or inside
  • how big the engine is. The bigger the engine is, the longer it takes to cool down
  • the efficiency and type of the cooling system
  • the material of the engine ie. aluminium built engines are quicker to cool than cast iron ones.
  • weather conditions if outside – rain, sunshine, shade, wind etc.

Now let’s move on to discuss the cooling and warming of the interior of the car.

How Long Does It Take for a Car’s Interior to Cool Down?

In the summertime, the interior of your car can get quite hot. Unbearably so. we hear stories of pets being left in cars and suffering seriously as a result.

The reason is that there are still hot parts inside your car, which are not cooled by the AC, and they are warming up all of your stuff really quickly.

How long does it take for a car’s interior to cool down? It depends on many factors, but generally speaking, it takes about 30 minutes for an average-sized sedan to cool down completely.

Is this correct? Well, I’ve looked at the test results published on this page at Thrillist and this is what I found…

Cooling in the First 10 Minutes – effect of Air Conditioning and Open Windows

  • Air conditioning full on. Stationary car. Closed windows. Start temperature was 128F Ten minutes latertemperature was 110F. Cooling rate: 1.8 degrees/ minute
  • Opening windows completely and turning AC to maximum. Moving car. Start temperature 126F. Windows closed after two minutes. After 10 minutes the car temperature was 101F. Cooling rate: 2.5 degrees/ minute
  • Air conditioning full on. Moving car. Closed windows. Start temperature was 138F. Ten minutes latertemperature was 107F. Cooling rate: 3.1 degrees/ minute

This shows that driving the car helps to cool it down and this is because movement helps the air conditioning work better as wind or airflow is needed over the condenser. The results were obtained in Texas in the extreme heat of summer.

How Long Cars Take To Cool Down

Hot days, hot cars. If you’ve ever stepped into a car that just came off of the lot and felt like you were stepping into an oven, then you know what we mean. A car that has just come off the lot can reach upwards of 130 degrees Fahrenheit.

We know it’s hard to believe, but this is true, and it only gets worse from there. When a car sits in the sun for a few hours in 110-degree weather, its interior can reach up to 160 degrees, which is hot enough to cook a casserole in minutes! Maybe even a Pizza??

So how long does it take for your car to cool down? The answer varies from vehicle to vehicle and depends on the outside temperature as well as other factors such as whether or not your windows are open or shut and as we have seen above if you use air conditioning.

So for different climates, the ideal cooldown time varies.

The Best Ways To Decrease The Temperature Of A Hot Car

Heat in cars is not just uncomfortable, it can be deadly. There is an interesting chart on this page that shows how quickly and how high the temperature in your parked car can rise depending on the outside temperature. It shows that even at relatively cool temperatures your car can heat up to 100 degrees F easily. So cooling time is important.

There are plenty of ways to lower the temperature of your car fast.

Many recommend first fanning the front door of a car 8-9 times to suck out hot air before you get into your car. The car needs to be driven for the AC to be most efficient and so get moving as soon as possible. Don’t turn the AC on immediately because it will first blow hot air into the car. Give your car a chance to use air movement for its first cooling then blast the AC.

Final Words

So there you have it! How long your car needs to cool down, both the engine and the interior. You can’t beat the heat, but there are many tips you can use to minimize the inconvenience and avoid any damage that heat may cause your car or the passenger. Happy motoring!

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