Coolant Blows Out Of Reservoir: Key Factors To Consider

Coolant or liquid inside the car must also be in a dedicated container. And a deficiency of even a tiny amount can have a lot of impact on performance.

In another aspect, the cooling water will unintentionally cause significant harm to the system leak. Coolant blowing out of reservoir is always one of the most severe problems you need to fix soon.

But don’t worry. I will provide vital information in today’s article to make the fix faster and easier.

Coolant Blows Out Of Reservoir

Where Is The Coolant Reservoirs Located In My Car? 

The coolant compartment is always inside the vehicle system, and you must intervene deeply to access it.

Depending on the manufacturer’s design, this part is usually shaped like a square or rectangular box. Most model compartments are made of plastic or plastic to prevent accidental chemical reactions. 

With all these features, you should be able to find reservoirs more easily among dozens of other components.

To be sure, we can search in the upper right area of ​​the engine compartment because most manufacturers put coolant reservoirs in this area. Of course, there will be some notable exceptions. 

Therefore, you should consult the documents that come with the vehicle in advance to determine the most accurate location of this mechanism.

Consequence Of A Bad (Failing) Coolant Reservoir?

The coolant spill from the reservoir will inevitably have serious consequences and significantly affect vehicle performance. 

In the following section, I will introduce you to some of the shared values of this phenomenon. Look closely because this information can be available in assessing severity.

Leaking liquid out

Blows out will cause a large amount of cooling fluid to leak to other parts of the system or the outside of the vehicle. 

Thereby a significant loss of this substantial amount of solution. The system’s heat dissipation performance is also severely reduced for this reason.

If leaked out of the car, the coolant will leave liquid streams scattered everywhere and affect the movement of other vehicles. Even if you park your car in the garage, dealing with this irritating chemical takes a lot of time.

Create smoke

Spilling the coolant out of the tank can cause smoke, even though the vehicle usually moves. This agent may not harm the car, but I am sure no one is uncomfortable encountering it.

The leading cause of the above situation is the reaction between the coolant and the heat.

Evaporation will occur much faster when liquids come into contact with high-temperature surfaces. And the substances that appear after this process are the ingredients that create the unpleasant smoke you are suffering.

Why Is Coolant Coming Out Of The Overflow Tank

Why Is Coolant Coming Out Of The Overflow Tank?

There are many causes of coolant blowing out of the reservoir. Problems can stem from temperature, the tolerance of many components, or failures in a few essential parts.

But in the section below, I will only cover the most common reasons for you to follow easily. From there, it is based on these characteristics to make appropriate judgments during manipulation.

Problems with the water pump

The coolant constantly moves throughout the system and exchanges heat in a closed system. So there will always be one or more pumps acting to create pressure and maintain this process throughout the vehicle’s operation.

If the pump stops working for some reason, such as system damage, broken components, or misoperation, the solution will not move.

The heat exchange process will stop at this time and cause the cooling water to heat uncontrollably. When reaching a specific temperature, the liquid will expand and increase in volume and cause blows out.

Broken Thermostat

The thermostat is the mechanism that plays a vital role in the heat distribution of the cooling water stream. When moving back from the engine, the liquid containing the heat will have to pass through the upper part to return to the original temperature and continue the old cycle.

So it is straightforward for the coolant to overheat if the thermostat is not working correctly, what the manufacturer has set in advance.

Just like the situation you would encounter if the water pump fails, the solution at this time will boil and create air bubbles due to not cooling down in time. Finally, when the expansion is large enough, overflow is inevitable.

Broken Head Gasket:

The broken head gasket is also one of the common causes of coolant overflow. His part plays a significant role in the operation of the cooling system.

But unfortunately, the head gasket is often exposed to external factors such as grease or mud. Over time, these impurities will accumulate and cause plaque or corrosion of the structure of this part.

Once the head gasket can no longer work stably, the fluid flows will also slow down or even stop altogether. The consequence of constantly keeping the temperature high will always be unpleasant blows out.

Bad Mixed Or Insufficient Coolant

You must always carefully consider the coolant’s quality before choosing and using it for your vehicle. Because in addition to problems with the system, this liquid can also be the cause of overflow.

The cooling water will need to maintain enough stability and heat-holding performance during travel. Heat dissipation will also be affected if the solution’s components have problems.

It is also why many poor-quality coolants heat up faster and have a relatively low boiling point. Combining all these disadvantages will cause the solution to reach the threshold of expansion quickly. As a result, the coolant will start to leak even though the system is not too hot.

Amoun of inappropriate Coolant

Usually, adding a large amount of solution will increase the overall volume inside the pipeline. At this point, a slight temperature change will trigger the expansion and push the liquid out of the container.

It is an issue that I’m sure we all know. Many situations like overfill power steering fluid  also produce the same phenomenon.

But only a few people know that adding too little of this solution can also cause blows out. In addition, the lack of cooling water is also a clear sign of problems related to the cooling system. And many of them will easily lead to liquid spills if you don’t find solutions early.

How To Fix Coolant Blowing Out Of The Reservoir

How To Fix Coolant Blowing Out Of The Reservoir? 

It is tough to access the coolant reservoir, and it is not easy to deal with errors from the related parts. Therefore, we will need to contact the experts to get the right help.

This action will help you quickly fix problems related to this error while ensuring the integrity of the surrounding details. While arbitrary manipulation will lead to many negative effects even for unrelated parts.

Price To Fix Coolant Blows Out Of Reservoir 

There is no fixed cost for coolant blows out of reservoir repair. Because each different department will require us to pay additional amounts to handle problems. In addition, centers will also apply relatively various labor surcharges.

But of course, there will still be a standard price range and you can refer to it before deciding to take the car for repair

  • Fan or bridge failure: about 20$
  • A thermal sensor: from 150$ or more, depending on the car model
  • Damaged pump: From 500$ or more
  • Handling problems related to leaks: Depending on the situation, the cost can range from $50 to $500

What Is The Boiling Point Of Coolant 

Typically, heat-controlled waters will boil at temperatures between 125 degrees Celsius and 130 degrees Celsius. In other words, this particular liquid will have a more challenging time reaching the boiling point than water or most solutions.

However, the difference is not higher than the average temperature of the components in the vehicle. Therefore, in many cases, coolant tends to boil quickly when the car operates at high capacity.

The above milestones are not fixed because many factors can affect the coolant’s boiling point. The structure, additives, and the external environment are the most typical example. These factors cause disparities, and you need to take special care not to make the wrong decisions.


What does it mean when coolant spits out?

Coolant spits out is a condition in which the heat transfer fluid spills out of the reservoir and leaks into the vehicle’s system. 

There are many causes for this condition, but mainly heat-related problems. Because the temperature change will cause the liquid to quickly boil and increase in volume abnormally.

How long will a car run with a blown head gasket?

A blown head gasket is one of the worst problems a car model can face. If you don’t handle it quickly and keep moving, you can only drive for another month.

Do head gaskets fail suddenly?

The difference in temperature can cause head gaskets to expand or contract continuously for a very short time. This sudden change will cause the said part to be subjected to a huge impact force and lead to immediate damage.

How does a mechanic diagnose a blown head gasket?

The most common method of mechanically determining a blown head gasket is to test for the presence of gas in the coolant. Of course, there are other ways, but this is the easiest option.

What is the best way to check a head gasket?

You can check simply by looking at the oil cap. The head gasket is still in good working order if this part is arid. On the contrary, in case the machine is wet or has a thick yellow fluid, there is a high probability that a leak has occurred.


Coolant blows out of reservoir is a dangerous condition that needs to be addressed as soon as possible if you want to move more safely. So please carefully consider the information I have given in the article and apply it generously to viewing and using the car.

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