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What Causes A Car To Overheat – 12 Possible Reasons

What Causes A Car To Overheat

Every vehicle has an engine system that works within a specific temperature range. As part of the engine’s function, it generates heat, increasing its temperature beyond the allowed level.  

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Luckily, the cooling system takes care of any access heat generated by the engine and cools it down.  It is completely normal for your cooling system to malfunction at some point over time of use. 

There is a long list of reasons causing your vehicle to overheat, whether it's related directly to the cooling system or other components in your vehicle. Whatever the cause was, vehicle overheating is something you must not ignore; otherwise, you might be dealing with a complete engine or vehicle failure. 

In this article, we will highlight the main role of your cooling system in your vehicle and how it works. Then, we provide a detailed explanation to answer your question of “what causes a car to overheat?” We list the top 12 causes for car overheating, as reported by automotive experts and customer reviews. Once you identify the possible causes of car overheating, you can easily pinpoint the best solution to take care of the problem.

How does the engine cool down? 


The cooling system is a very important part of your car. It is best to understand what it is and how it works before we get into the details of what causes a car to overheat. 

The cooling system consists of several components, including a water pump, Radiator, CTS (cooling Temperature sensor), a coolant, and a Thermostat. 

Following a specific cycle, the water pump pumps the coolant around the engine to cool it down. 

The coolant fluid travels around the engine, picking up the heat on its way.  When the fluid starts to get warmer, it returns to the radiator to transfer the gained temperature and cool down. 

The thermostat works as a valve allowing the coolant to pass around the engine only when the engine’s temperature rises above the required level. This is because the vehicle doesn't need the coolant to flow continuously around the engine and cooling it down all the time; the engine must get to a certain temperature level to perform efficiently. To do so, the thermostat relies on the cooling temperature sensor to determine the right timing for allowing the coolant to pass through. 

Over time of use, any component of the cooling system can malfunction, resulting in engine overheating. Unfortunately, engine overheating is not something you can ignore; otherwise, you might deal with engine destruction. 

Causes for an Overheated Car


There are numerous causes for your vehicle to overheat. It could be from your coolant system, or even because of the engine itself. In general, the majority of car overheating issues are usually related to the cooling system. In this section, we provide a list of 12 common causes of car overheating.


  • Problems with Cooling System



As we mentioned earlier, your cooling system is the primary part responsible for keeping your engine’s temperature within the specified range.


Thus, when your vehicle overheats, the first thing you would need to check is your cooling system cycle. Check for any disturbance or any issues with the connection. 

If you are not able to pinpoint the issue within your cooling system, the best option for you is to take your vehicle to a professional mechanic and have it inspected.



  • Damaged Hose



The coolant fluid must cycle around the engine and within the cooling system smoothly using a set of pipes and hoses.   


Over time of use, the pipes and hoses can get partially or completely clogged, resulting in small to sever cooling engine damage. 

In most cases, the pipes clogging is partial, and thus, you might not detect the problem immediately. 

To avoid getting into such a situation, you might need to consider performing regular maintenance or at least inspection of your pipes and hoses in your vehicle’s cooling system. Professional mechanics are educated enough to detect any clogs in your vehicle’s pipes and hoses. 



  • Fluid Leaks 


For your vehicle to function properly without overheating, a specific amount of coolant must be maintained within the cooling system. If this amount drops, the coolant will not be able to accommodate the increase in the engine’s temperature, and therefore, not cool it down. 

If you notice green liquid underneath your vehicle, it is most certainly a coolant leak. If you notice it to be any bigger than a small puddle, it is pretty serious. 

In sever leaks scenarios, you might not even drive your vehicle and must get it towed to the nearest mechanic. Otherwise, you might scarify your vehicle’s engine. 



  • Low Coolant Fluid



Your vehicle’s coolant might drop, not only due to clear coolant leaks but also due to overuse. For example, if the vehicle has a very small leak, the coolant might evaporate right after it leaks out of the cooling system. As a result, you might not see any drops of fluid or fluid puddles under your vehicle. 


Therefore, it is important to maintain a regular coolant level check instead of relying on visual inspection for coolant leaks.

If the problem is detected early, there is a high potential of saving your vehicle’s engine. Otherwise, delaying such a problem could result in significant problems requiring high repair costs, as we mentioned earlier.



  • Little Oil



As we stated before, sometimes the problem causing car overheat doesn’t necessarily relate to the cooling system; it could be the engine itself. 

For instance, if there is a drop in your engine’s oil, it is not surprising to deal with vehicle overheating. 


Your engine’s oil is responsible for ensuring good lubrication and prevent friction between moving engine parts. 


If the engine did not have the required amount of oil, its internal components would generate excess heat due to friction. As a result, your vehicle can overheat. 


Therefore, you must maintain a regular inspection of your vehicle’s engine’s oil. You might also need to keep an eye on any oil leaks under the vehicle after parking. Oil’s leak will look very different than coolant leak. You can confirm that by checking either the color or the smell of the fluid puddle under the vehicle. 



  • Uneasy Thermostat 



As you know, the cooling temperature sensor gives the coolant system a signal that the engine is overheating. Some issues with the thermostat can result in significant engine overheating. 


For instance, the thermostat can get stuck closed overtime of use. Imagine when the thermostat is closed, the coolant will not pass at all, even if your engine’s temperature gets very high. 


Thus, you can perform a visual inspection of your engine’s thermostat and see if it is stuck closed. You must follow the safety procedure before performing any inspection around the cooling system as all components can be extremely hot.



  • Wrong Coolant 



Every vehicle is manufactured in a certain way requiring a specific type of coolant to handle the engine’s temperature.


The best place to get information about your vehicle’s coolant type is the Vehicle's Owner’s Manual; it should specify what kind of coolant your car needs. 


Many people accidentally end up replacing the wrong coolant. As a result, the engine can overheat or get damaged in difficult situations. 


Thus, you must ensure using the right coolant type. If you don’t have a copy of your vehicle's owner’s manual, you can request a copy from your mechanic or download a soft copy from the internet. 



  • Faulty Radiator Fan  



The Radiator Fan brings air across to the radiator, cooling down the coolant fluid. If your radiator fan is broken or worn out, your coolant fluid won’t cool down, causing the car to overheat. 


Thus, you must maintain a regular inspection of your radiator fan to avoid getting into such a situation. Once you ensure its the radiator’s fan, do not delay fixing the problem and have it replaced immediately. This way, you don’t need to deal with more complicated problems like engine destruction. 



  • An Airlock



Coolant leaks may cause an airlock or air bubbles due to air piles up in a tight zone. Too many air bubbles in the coolant can disturb its effectiveness in cooling down the engine.


Detecting an air bubble in the coolant is not something you can do. Unfortunately, only a professional mechanic with specific tools can confirm its airlock causing the vehicle to overheat. 



  • Loose Radiator Cap 



The radiator cap is what keeps the cooling system in place. You must understand that if the radiator cap is not closed tightly, the cooling system will not function properly. Even if it is a little loose, it can still result in engine overheating. 


Therefore, when you open the radiator cap for any reason, you must ensure it's closed and secured properly. Sometimes the radiator cap becomes loose over time of use; in this case, you must get it replaced by a professional mechanic as soon as possible to avoid other significant problems.  



  • Radiator Clogged



Over time of use and as the coolant gets older, the radiator can get clogged due to dirt or debris from inside or outside the vehicle. While this might not be a significant problem, it is always recommended that you clean your vehicle’s radiator frequently. 


The more you wait, the more significant the problem can get, and the higher the repair costs you have to deal with. In some situations, major clogs can result in damaging the entire radiator.



  • Too Much Weight



The last problem we would like to highlight here doesn’t have to do with the cooling system. It is just a general common sense.


Several automotive experts indicated that overloading your vehicle beyond its capacity can result in engine overheating as the engine tries to resist the weight. 


For instance, if you are traveling with a trailer that is 7,000 pounds, but your vehicle can only pull 4,000, the engine will be challenged to handle this weight and thus generate more heat resulting in vehicle overheating. 

Is it worth fixing engine overheating?


The short answer to this question is yes, and no. Depending on the type of problem and your vehicle’s condition, you might need to consider fixing or getting rid of your vehicle. 

For example, if you know that the overheating problem is due to significant issues with your engine that requires very high repair costs, it might not be worth fixing it.

On the other hand, if your vehicle's problem is due to a simple issue like the radiator’s fan, fixing it will not require a lot of time, money, or effort. Thus, it makes sense for you to get it repaired. 

Bottom line, when deciding on any mechanical repair, whether it’s vehicle overheating or anything else, you must evaluate the overall situation of your vehicle before spending any money.



It is very common for your vehicle to overheat due to several reasons. In most cases, car overheating happens because of issues with the cooling system. 

The cooling system controls the temperature of your vehicle at all times. The system consists of many parts such as the thermostat, CTS (cooling temperature sensor), coolant, and a water pump. 

The coolant fluid travels around the engine, cooling it all down. The thermostat sends a signal to the system, telling them to bring out the coolant fluid when the engine overheats. When the engine cools down, and the fluid warms up, it travels back to its original spot to regain its right temperature. 

If the coolant cycle around the engine got disturbed, the first thing you will see is car overheating. Car overheating is a significant problem that must not be ignored to avoid dealing with complicated issues with your engine that can get as severe as a complete engine failure. 

Therefore, if you noticed any engine overheating, you must get your vehicle inspected by a professional mechanic as soon as possible. 

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