What Happens If You Overfill Coolant

What Happens If You Overfill Coolant – Is This A Bad Thing?

Have you ever wondered what happens if you overfill coolant? Well, if this is the situation and this is the question that bothers you, then you are at the right place because there will be a lot to cover on this topic.

Engine coolant is one of the most essential fluids in our vehicles that allow us to run our cars as it should. And the level of coolant is one of the things that we need to be most aware of. Meaning that if you run your engine with low coolant, the car could overheat. But what happens if you overfill coolant? Well, more on that we are going to cover a bit later in the article.

Nevertheless, coolant is very important and you should always keep an eye on it and make sure that is always above the minimum and above the maximum level. This is your obligation as an owner if you don’t want something really bad that can happen to your engine if you don’t make sure that this is always the case. And later in the article, we will learn the consequences of both situations.

First, we will learn what is coolant and what are the different types of coolant out there. Then we will see how the cooling system works on a car. Later, we will see what will happen if you underfill the coolant and also what will happen if you overfill coolant. Then we will cover what you could do about this problem. So, if you want to learn more, follow along.

What Is Coolant, And What Happens If You Overfill Coolant?

Before we jump into more complex topics, let’s cover some of the basics when it comes to the coolant. Let’s learn something about the coolant and its properties. This will be quite handy for beginners who are new to cars and want to learn more. If you know more about this stuff, feel free to move to more complex stuff like what happens if you overfill coolant. If not keep up with us for a bit.

So, what is coolant in general? A coolant is a special liquid that is used by your cooling system and this coolant helps your car to cool off the engine.

The engine coolant has heat dissipating properties that make it a better alternative than water. If you use water, you might even overheat your engine. But why is this the case?

Well, this is the case because the coolant has a much higher boiling point than your regular water. It doesn’t matter if you put tap water or distilled water, they will both perform in the same way. Which is quite poor, to be honest.

Your engine will overheat sooner or later. But this isn’t everything you need to know about coolant. Because coolant also helps your engine not to freeze in the winter. That’s right engine coolant has an extremely low freezing point and can withstand a lot during those long winter days when temperatures are below freezing point.

Considering these two aspects, you can understand why coolant is so essential for its use in internal combustion engines. Without this solution, engines will not last for a long time and you will have to replace them much sooner like back in the day. But what happens if you overfill coolant? More on that in a bit.

Is Coolant And Antifreeze The Same?

Now before we dive into learning more complex topics like the question of what happens if you overfill coolant? Let’s answer one very interesting question that bothers a lot of people. And that is whether or not coolant and antifreeze are the same thing.

Many people are scratching their heads when it comes to this situation when they see some different stickers. One says coolant and the other says antifreeze. So, is there any difference?

Well, in reality, there is none. Both of these solutions are pretty much the same thing. So, you should not get alerted and confused if you notice this when purchasing coolant for your car. A jug of antifreeze will do the trick just fine.

Just beware of what you purchase because some coolants out there are coolant concentrate. While other coolants are already diluted.

So, you need to understand the difference between a concentrate and a coolant mix. The concentrate is 100% pure coolant. While the coolant mix is already diluted and doesn’t require further dilution. But what happens if you overfill coolant? We will get to that in a bit after we cover the different types of coolants out there.

Different Types Of Coolant; What Happens If You Overfill Coolant

Now before we cover what happens if you overfill coolant, let’s learn more about the different types of coolants that are out there. As you know, there are a ton of coolants that come in a ton of colors. It is really difficult to track them all and know all of them. Fortunately, they are separated into three groups IAT (inorganic acid technology), OAT (organic acid technology), and HOAT which is a hybrid of both of these different technologies.

IAT or inorganic coolants are produced from ethylene glycol. This is an inorganic solution and a rather toxic solution. Especially for animals who are attracted by the sweet smell of this coolant. This is usually the green coolant used on cars up until the 90s.

OAT or organic coolants are a separate family of coolants that are based on organic compounds. The OAT coolant is manufactured from propylene glycol which is an organic compound and also less toxic than the ethylene glycol-based solutions.

HOAT coolants are the most common coolants nowadays. These are a mix of the two solutions and perform the best when it comes to cooling off your engine. They have a lot of protective abilities. Namely, these coolants stop corrosion and improve the work of the cooling system in general. But what happens if you overfill coolant? That’s what we are going to cover in a bit. Now let’s learn how the cooling system works in general.

How The Cooling System Works In A Car?

Now before we cover what happens if you overfill coolant, let’s learn how the cooling system works in a car? What are the main components of the cooling system and how to understand it better? So, if you want to learn more, follow along.

The cooling system is a really simple circulating system that each car with an internal combustion engine has.

The core of this system is the water pump. This powerful pump makes sure that there is a proper flow of the coolant inside and outside of the engine block. This pump is powered by the accessory belt.

When you start your car and the coolant gets warmed up, another component which is the thermostat opens. When the thermostat opens, this means that the engine has reached the operating temperature and releases the hot coolant out of the engine and cold coolant gets inside of the engine.

At the bottom and at the top of the engine there are two coolant hoses. An upper radiator hose and lower radiator hose. And as you are guessing, they go directly into the front radiator.

The front radiator is a device that is mounted at the front of the car which helps cool down the coolant with the help of air drag. If there is not enough air drag, the fans that are installed on the radiator will kick in in order for the cooling to be possible.

Overall, these are the most important components that you need to know when it comes to the cooling system. But not to forget the expansion tank which is also another really important device that allows the pressure to be released. But what happens if you overfill coolant? We will get to that in a bit.

Proper Coolant Mixture

Now before we learn what happens if you overfill coolant, let’s cover another topic and that is the proper coolant mixture. This is a question that bothers a lot of people and it is quite useful for you to learn what is the proper coolant mixture.

The engine coolant or antifreeze comes in two different types. Pre-diluted coolant, which means that this coolant is already mixed and you can just pour it into the cooling system.

The second type is coolant concentrate. This coolant concentrate has to be diluted with distilled water. So, you might watch out before purchasing the right coolant because if you pour 100% coolant concentrate it will corrode your cooling system and your car will perform badly. The concentrate has to be diluted at least with 30% water. This is recommended if you live in colder environments where temperatures are getting really low during the winter.

The proper coolant mixture in normal conditions where climates are relatively warmer is a 50/50 mix. Meaning that you pour 50% coolant concentrate and 50% distilled water.

Distilled water is essential. You don’t want to use tap water because tap water has minerals and other components that will make the coolant perform poorly and will corrode your system quicker. So, beware of this thing before you flush your coolant. But what happens if you overfill coolant? We will get to that in a bit. But now let’s see what is the proper coolant level.

Proper Coolant Level

Before we dive into what happens if you overfill coolant. Let’s see what is the proper coolant level. What coolant level is ideal for your car to run properly? Let’s elaborate.

In order to determine this, you need to locate the coolant expansion tank. It is important to note that this is not the radiator that you have on your car where you top off the coolant.

This expansion tank is a separate plastic tank that is located usually at the side of the engine. Some manufacturers include it on the left side, some on the right, some near to the firewall. It really depends from application to application.

But what is the important thing is that this expansion tank is usually while with a yellow cap on top of it. Next to the cap, there is a valve that releases the pressure from your system in order to prevent some hoses from popping out.

On the coolant expansion tank, there are two marks. One of them says “min” and the other says “max”. You should always track this level and make sure that the coolant level is somewhere in between. That is the right coolant level in your car.

If you overfill the coolant, you will start asking yourself what happens if you overfill coolant? Or if you underfill the coolant you will ask the opposite thing. And what happens in both situations we are going to elaborate on in the following chapters.

What Happens If You Underfill Coolant?

Now before we cover what happens if you overfill coolant, let’s first see what happens if you underfill coolant? What will happen if you mistakenly leave your car with a low coolant level that is below the minimum level in the expansion tank? Or if the expansion tank is completely empty, let’s elaborate on that next.

1. Air Will Get Into The System

The first thing that will happen if you underfill coolant is the air inside of the system. This can also be caused by a bad radiator cap.

But if the coolant level gets too low because the coolant somewhere is lost, it is obvious that you will have air in the system.

So, this air will cause the cooling system to become depressurized. Resulting in the coolant coming to a boiling point and sometimes if there is too much pressure. The overflow tank can explode.

This will create a huge mess inside the engine bay. It doesn’t happen a lot. But when it does it will create a big mess. So, if the coolant level is low, it means that you lose coolant and this problem needs to be sorted out as soon as possible. Now before we cover what happens if you overfill coolant, let’s learn the second problem that you might come across if you leave your engine without coolant.

2. Engine Will Overheat

Now let’s cover the second thing that happens if you underfill coolant and that is the engine overheating. The engine will like to get hot if there is a low coolant level inside of the block.

This low coolant is not a good situation and could cause a chain reaction that will make other components fail. Namely, the head gasket material will burn and cause even more damage inside of the engine.

The gasket is the one that separates the engine block from the engine head. And without this component, the engine will not work as it should. So, if you run your car with low coolant for long, the first thing that will fail will be the head gasket and the engine will overheat.

As soon as the engine gets overheated, the engine head will get bent and you will start to lose performance. Eventually, the engine will stop working because it overheated too much. In worst cases, you will even have to replace the whole engine. That’s why beware of this. But what happens if you overfill coolant? Well, that’s what we are going to cover next.

What Happens If You Overfill Coolant?

So, we came to the important bit and that is what happens if you overfill coolant? What are the possible consequences and repercussions of this action?

We all make mistakes in our lives, some of us more while some of us less. This fortunately is not such a big deal as the situation when you run the engine with low coolant. But it could cause some damage and you need to be aware of it. That’s why we are going to cover all of the different scenarios when it comes to this question of what happens if you overfill coolant. So, if you want to learn them, keep up with us.

1. Mess In The Engine Bay

The first thing that will happen if you overfill coolant will be the mess in the engine bay. As you know, the coolant level should be below the max and above the minimum.

If you fill the coolant right to the top and the expansion tank doesn’t have any free space. You risk an explosion of the expansion tank.

What Happens If You Overfill Coolant

As you know, the cooling system is pressurized and this pressure buildup will do nothing good to your system. The expansion tank will explode or a lot of steam will be constantly released by the expansion valve and this will cause a big mess inside of the engine bay.

Your engine will be covered with coolant. And this is not good. So, that’s what happens if you overfill coolant. Now let’s cover the other things that could possibly happen when you overfill the coolant.

2. Damage To The Electronics

The second thing that happens if you overfill coolant will be the damage to the electronics. This often happens if you have a fusebox next right next to the expansion tank.

The expansion tank could fail or explode in some cases and all this coolant will go somewhere. And that is on these electronic components.

When the coolant gets in touch with electronics it will make it too short out and eventually not work. So, more work will be needed to be done to return the car in proper working condition And this work is really expensive, you don’t want to replace complex electronics on your car. Now, let’s move to the last thing what happens if you overfill coolant.

3. Leaks Of The Cooling System

The last thing that happens if you overfill coolant is the leaks from the cooling system. If the expansion tank doesn’t fail, there will be another failure point.

These failure points are usually the clamps that are holding the upper and lower radiator hoses. The hoses can also crack from too much pressure, and the radiator can fail as well.

All these components are possible failure points and that’s why you need to stop questioning what happens if you overfill coolant and move to action. And that is how to remove the excess coolant from the system? And that we are going to answer next.

How You Can Remove Excess Coolant?

Now after we learned what happens if you overfill coolant, let’s move to real action and sort out this problem. Because you probably don’t want your hoses or expansion tank to explode. What you can do in this situation? It is very simple.

You just go to the pharmacy and get the biggest plastic syringe that you can. Needles are not necessary since we will use this syringe to extract the excess coolant. You can also use a cooking syringe if you have one around. Or even a plastic hose. Everything works.

Just be sure that you get the coolant out from the expansion tank and assure that the level is at the right mark.

Can You Keep Driving With Overfilled Cooling System?

We learned what happens if you overfill coolant, now let’s see what happens if you do so. And the answer is really short. You get failure of the cooling system.

What Happens If You Overfill Coolant

Especially if you press the car hard and it really warms up. Then who knows what is going to happen. As we said, the expansion tank can fail, hoses and clamps can fail, and even the head gasket that we haven’t mentioned can fail if there is too much pressure in the system. So, beware of this and make sure that the coolant level is at the recommended factory mark. If else, you will face the consequences that we covered.

Conclusion To What Happens If You Overfill Coolant

In this article, we have covered quite a bit when it comes to the question of what happens if you overfill coolant. We learned first the basics of what coolant is and what is its function. Then we covered the different types of coolants and how the cooling system works.

Then we learned what will happen if you underfill the coolant and we also learned what could happen if you overfill the coolant. And the results are not good. There will be an increase of pressurization in the system, resulting in failures of the expansion tank or some other components on the cooling system.

Lastly, we learned how you can remove the excess coolant and that could be done simply with a syringe.

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