Automotive

How Long to Let Engine Cool Before Adding Oil? EXPLAINED!

Engine oil is a very important thing that you need to consider for your can engine. And it is your responsibility to hold the engine oil at a healthy level. Here we will explain how to add engine oil to your car engine. And we give the exact answer to the question “How long to let engine cool before adding oil?” people are asking. 

How Long to Let Engine Cool Before Adding Oil? 

How Long to Let Engine Cool Before Adding Oil? 
Engine oil cap and stick.

Different sources are explaining this for 20-30 mins. But there are certain things that you need to know about it. 

If you worked your engine for hours from a long drive, you need to wait at least 30 minutes before adding oil to your engine. Because the temperature of the engine and oil raise because of the constant motion of the oil inside the engine. 

Also if you run the engine for a short time the engine could not find enough time to increase the temperature of the engine and engine oil to the highest point. In this case, you can wait 156 min and add oil to your engine. 

The temperature of the environment is also very important. If you run your engine on very hot days on summer days when temperatures reach 40 degrees Celsius, you need to wait up to 40 min after a long drive. Because the heat transfer between the environment and engine components and engine oil is not at the highest point at that stage. So you need extra time for the required cooling process to take place. 

Furthermore, on cold days, you do not need o wait too long to wait the cooling o the engine oil. The oil will cool down rapidly in freezing colds. So in general 10-15 minutes will be sufficient to obtain the cooling of the engine oil effectively. 

So you need to assess the situation for your car. And you can decide to choose the best duration to wait to add oil to your engine. This is the general answer of how long to let engine cool before adding oil question.

Why We Wait to Add Oil to the Engine? 

There are several reasons that we are waiting for it. While you are re-changing the engine oil, you need to check the level of the oil since the oil sump of your engine. You are doişng it by checkhşng the oil stick of your car. 

For those who do not know how to check the oil level, you need to take the engine oil checking stick by holding it from its handle. 

Once you took the handle, you need to clean the oil at the end of the handle with a viper. 

And you need to attach the stick to its place again and took again. And check the oil level between the two lines. If the oil level is below the bottom line, you need to add additional engine oil to the engine to take the oil level to a sufficient level. 

And also if the engine oil level is above the upper line, you do not need to do anything.ç The engine will adjust the oil level to a sufficient position. 

This is how we decide to add engine oil to the engine.

So, we can easily understand the logic here. Because of the heat of the engine, the temperature of the engine oil increases. Because of this, the engine oil expands. And because of this expansion, the reading of the oil level will not be correct. So we need to wait for sufficient time to read the correct time for the engine oil.

Also if you deal with hot oil, there can be bad accidents happens. If you run the engine for long times, the engine oil temperature can increase up to 90 degrees Celsius. And if you touch it with your hand, you can have very bad accidents. To prevent it to happen, you need to wait until the engine oil cools down to sufficient levels. 

Are There Any Dangers to Add Oil on Hot Oil? 

There are different kinds of rumors about it. For example, some people say that the engine block will crack if you add it directly. But there are no kinds of this situation. 

The crack of the engine block can take place because of the exposure to heat instantly when it is cold. But in this case, the engine is hot. And there will not be any kişnds of chance that the engine block will crack. 

And another thing that we need to state is that you are adding the engine oil to the oil sump. The oil sump is made from a malleable aluminum that will not crack because of the temperature changes. So you do not need to worry about cracking the engine components in addition to cold oil. 

Another thing that we can state is that the feature of heat absorption of oil is not fast like water or other liquids. So, when you add cold oil to the engine, the heat transfer between the hot oil and cold oil will not be abrupt. And there will be no danger for it. 

Take Care About Your Engine Oil Level! 

Check engine oil level.
Check engine oil level.

There are different duties of engine oil that you are adding to your engine. The first and most important duty is the lubrication o the engine components. You know that engine comprises lots of moving parts. And these moving parts are contacting with each other to work properly inside the engine. Without a sufficient level of oil inside the engine, the engine components will hurt and the friction between the components will deteriorate the engine. 

Open the engine oil cap to add oil.
Open the engine oil cap to add oil.

So, engine oil is a very vital thing that you need to check every day that you are using your car. Make sure that you have the proper engine oil and add the engine oil to have a sufficient amount of it. 

Another important duty of the engine oil is maintaining the engine temperature at a specific level. Because like the cooling fluid, engine oil act as a cooling fluid inside ethe engine components. It absorbs the excess heat from the engine components and withdraws the heat in the sump. 

As you can understand that it is very important to check the engine oil. And you need to be sure that the oil level is at the sufficient level that maintains the car. 

How to Add an Engine Oil? 

Take the stick.
Take the stick.

If you see that the engine oil is low for your car from the oıil stick, you can easily add oil by following these steps; 

  • First of all, you need to open the engine oil cap as you see in the picture. 
  • After that attach a funnel to the cap to prevent spillage of the engine oil into the environment. 
  • And spill the engine oil into the engine. Do it by checking the engine oil level from the stick to obtain the correct level regularly. 
  • Once you completed the engine oil spillage, close the cap of the engine oil bottle to prevent contamişnation. And take the funnel from the oil cap. 
  • Tightly close the engine oil cap. 

As you see above, it is very easy to close the engine oil cap like above. 

Attaching the engine oil stick.
Attaching the engine oil stick.

Also if you are driving modern cars, you will have a notification on the dashboard if you running without engine oil. The engine oil sign will be like below. And if you notice this sign you need to add oil to your engine. 

Last Words on How Long to Let Engine Cool Before Adding Oil 

We explained all the important details about the how long to let engine cool before adding oil. You need to assess the situation according to yourself. And check the temperature of the engine, and the temperature of the weather and decide how long you need to wait. 

Be sure that you have enough amount of engine oil inside your engine. 

These are the general things that we can state about engine oil. If you have additional comments and questions about it, leave them below. 

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FAQ 

Can you add oil while the engine is hot? 

Yes, you can add oil while the engine is hot. But the oil level reading from the oil stick will not correct when the engine is hot. Because the engine oil will expand because of the heat and you will not read the correct oil level from the stick. So, it will be better to wait to the engine will cool. 

How long does it take a car to cool down to add oil? 

In general, it will take around 20-30 minutes in most cases. But if the weather is hot and you run your engine for a long period, it will be better to wait for 40 minutes. 

Is it better to add oil to the hot or cold engine? 

The cold will be better. Because you can correctly assess the engine oil level when the engine is cold from the oil stick. 

What happens if you put oil in a cold engine? 

It is completely safe to add oil to a cold engine. 

References 

Car Burning Oil: How Much Consumption Is ‘Normal’? – Cars.com

Understanding How Engines Consume Oil – Machinery Lubrication

How to Change Your Oil – Car and Driver

Uğur Uygun

Hello everyone, I am Uğur. I am a mechanical engineer who has experience in different R&D departments of HVAC companies. With my best friend, I decided to build this website to share out knowledge and experience. And also, I am interested in automotive. So, I am writing about automotive and automotive-related articles here. Sharing my knowledge and experiences on these topics is a very big pleasure for me. I am willing to answer all of the questions people have about these topics.

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