Car Overheating: Main Reasons And How to Prevent

Car overheating! First of all, you don’t want this to happen to your car. It is a seemingly small defect that may result in more significant damage than you can imagine, both to the vehicle and the owner’s safety. So why would a car overheat? The simple answer is due to a malfunction in the vehicle cooling system.

The cooling system works to cool down the heat emanated from the engine of a vehicle. However, the cooling system comprises several parts that work together to affect the cooling effect required for the car’s regular running.

Overheating damages the engine, the vehicle’s nucleus, and the reason a car can function.

Reasons for Car Overheating

  • Using the Wrong Type of Coolant

 This is a common mistake whereby the cooling system is practical and functional, but you use the wrong choice of coolant for the particular vehicle. In other instances, it is the ratio of coolant to water that is the issue, which may lead to overheating.

What is commonly referred to as coolant is simply a 50/50 combination of antifreeze and distilled water, which is mixed together to form the fluid that cools the car.

It is essential to get all this information when acquiring a new motor vehicle to ensure that it is taken care of. Everything including how to mix up coolant is available from the manufacturer.

If you have any doubts about coolant choices, it is best to seek advice about the same well before complications arise. If you use the wrong coolant, the entire cooling system will need flushing.

  • Leakage

The cooling system pathway comprises many passages along which leakage may occur at any point. Mostly, the coolant leaves the engine to the radiator, and during this process, it the air passing through the car grillecools it. In between the engine and radiator is a thermostat. Still within the system are freeze plugs, a water pump, and the head gasket.


If coolant leaks out at any point within these parts, it will seep out slowly, and eventually, the vehicle will overheat. This is because there will be insufficient fluid to cool down the heat from the engine. 

Leaks are hard to detect, but if you suspect a possible leak, add coolant to ensure a sufficient amount then take the vehicle to for appropriate diagnosis to identify the leakage point and have it fixed. 

  • Malfunctioning Parts 

The cooling system is dependent on all its components functioning well. Any shortcoming from any of the parts affects the whole mechanism. 

If the water pump, for instance, breaks down, there will not be enough pressure to channel coolant within the cooling system, and this will lead to overheating.

If the radiator is faulty, it will be impossible to propel air across the radiator, meaning the coolant will pass through. Still, it will not be cooled down, and within a short duration, overheating will occur.

The thermostat functions to determine what happens to the coolant as it flows through the cooling system. All this is dependent on the temperature. If the temperature falls lower than a certain threshold, the coolant is diverted away from the radiator and flows back to the engine as there is no need to cool it further.

If it is not working, there would be no regulation whatsoever whether the temperature is high or low and could lead to overheating. Sometimes, the thermostat might also lock while closed, inhibiting the coolant movement, which would cause the engine to overheat.

Belts from the water pump and/or radiator fan could also break and interrupt movement within the cooling system. The same applies to hoses with wear, tear, or cracks.

 All these will get in the way of the coolant’s normal flow, causing leakage and eventually overheating. All these small malfunctions are redirecting coolant or inhibiting its flow, hence causing the vehicle to overheat.

  • Impaired Heat Conductivity

There might be a problem with heat conduction within the engine, causing it to overheat. This is caused by accumulated deposits, old coolant, and debris in the water pump jacket.

  • Low Motor Oil

 Contrary to its most common use of lubricating movable parts, oil plays a role in cooling the engine. It removes excess heat from the engine, and if oil levels are low, the engine runs too hot, causing overheating. Most people overlook this, but it is a major contributing factor in keeping the engine cool.

Tell-tale Signs That your Car May be Overheating

There is no easy way to tell that there is a problem with a vehicle’s cooling system. However, a few pointers to look out for include:

  • Dashboard indicator

This will be able to show you if your car is overheating as the temperature gauge will move to H. By the time this happens, it is a matter of urgency, and the sooner the issue is resolved, the better for your car.

  • Engine Noise

When a car overheats, the engine oil gets heated and becomes thinner as some components of it evaporate. The new lightweight composition of the oil is ineffective as a lubricant, and the movable parts are meant to be lubricated, run dry, become creaky, and produce an irritating noise. This noise is a symptom that should inform the driver of trouble within the engine.

  • Hot air from Air conditioning

Once this happens, there is no immediate need to worry as it does not necessarily mean that the engine is overheating. Still, it is a warning sign that something is amiss and a heads up to have the vehicle cooling system checked.

  • Smoke

The smoke released from under the hood of the vehicle is never a good sign. It does not necessarily translate to overheating, and it could be a result of other faults. However, if the coolant hoses burst, then it is likely to emit steam from underneath the hood.

  • Leaking Coolant

 This requires a lot of keenness to notice, but sometimes you might notice drops or a puddle of liquid underneath your car. There is much likelihood that this could be coolant, and if it’s leaking, it means its levels have gone down and probably requires topping up.

  • Difficulty in Acceleration

 When a car overheats, the cylinder pistons expand, become rigid and limit the scope of rotation of the crankshaft. This causes a delay in acceleration or total inability of the vehicle to accelerate beyond a certain point.

What to Do if Your Car Overheats

 If you are driving and the temperature gauge shifts to H this is what you need to do:

  • Slow down and engage the lowest gear you can drive while looking for somewhere to pull over. It is important to be off the road.
  • If the air conditioning is on, turn it off immediately.
  • Keep the fan on high to keep the temperature as cool as possible. If you can, roll down all the windows as well as the vehicle will get quite hot.
  • Keep the defroster on and heat on hot to divert the heat away from the engine area.
  • When the vehicle has stopped after finding a suitable place to park, step on the gas and rev the engine to about the 2nd mark. This should help lower the heat a little and the pointer to move slightly away from the H mark.

If it does not move, turn off the car entirely and consider having a mechanic take a look. Alternatively, have it towed away for fixing.

  • If you are well conversant with the internal structure of your car under the hood, check for signs of leakage.  Call for assistance if any. If none, the coolant level could be low, so you can check that and add some more if the level is low..

After a refill with coolant, give the vehicle some time to cool down then start the engine while checking the temperature gauge if it goes lower. If not, then call for assistance.

 Consequences of a Car Overheating

 What does a car overheating translate to? There are a couple of effects that might be resultant of this.

  • Engine trouble

 When the engine overheats, it could lose power or potentially stop working. The damage could extend to other parts of the car and destroy or damage pistons and rod bearings.

Repairing a damaged engine can be a tall order and requires a professional’s attention, and it does not come cheap. What’s worse is if it breaks down completely, and the only solution is to install another engine altogether.

  • Damaged Head Gasket

The gasket head is made from metal, most commonly aluminum, a good conductor of heat. Under immense thermal exposure, the metal expands gradually, and the pressure eventually presses too hard on the gasket causing it to crash. Repairing this is also quite expensive.

  • Cooling System Damage

Coolant can be quite corrosive and is capable of damaging different parts of the cooling system. When a leak goes undetected, the liquid seeps through the channels. If left for long periods, its corrosive properties can destroy the hoses, thermostat housing, water pump, and other parts.

When overheating is detected and resolved, a thorough inspection of all the parts along, it must be done and surrounding parts if there is any corrosion. Of utmost importance is to check the water pump, radiator, coolant system, level of engine oil, and the thermostat.

How to Prevent Overheating

Generally, taking good care of a vehicle will prevent such problems from occurring. Regular service and fixing small issues when they arise is an excellent place to start.

The early diagnosis of the problems comes in handy and, more often than not, is cost-friendly to fix. The longer an issue remains unattended, the more complicated it becomes, the more difficult it is to fix and the more cost implications it will have.

 The following measures will go a long way in preventing overheating:

  • Using the right coolant and checking its level frequently.
  • Being on the lookout for leakages at any point and, if unsure having your mechanic do it for you to be on the safe side.
  • At the point of purchase, have all the details on the same clarified so that you are aware of the frequency with which to have the cooling system flushed and cleaned to avoid the accumulation of substances within the channels.
  • Change up your oil regularly.
  • Replacing the car battery after a few years. Old batteries had reduced power and may not have the capacity to perform as it were when the car was newer. As a result, it may prompt strain and the car to work harder, making it overheat. Thus, with guidance from your mechanic, he/she should advise when it is appropriate to get a new battery.
  • Park your car in the shade always if possible. The sun may not cause the car to overheat directly, but you want to maintain the car as cool as possible as a way of taking care of it and minimizing the likelihood of any damage.


In summary, car overheating is a problem that can is avoidable. It is a simple system that only requires maintenance of certain temperatures and below to keep the engine in a good and functional condition.

Regular service and maintenance checks are the keys to preventing this and other car problems. Important to note is that the opposite is true as well.

Overcooling is a thing and has adverse effects on a car. Not as detrimental as overheating, but it is advisable to be cautious to avoid it as well. When a vehicle is overcooled, the oil may not be able to reach its optimum operating temperature impairing lubrication and causing damage to movable parts.

Condensation of fuel could also lead to the formation of carbon, leading to sludging and reduced life of the oil. So the goal is to maintain a balance, ensure engine temperature is within the recommended range, and to seek professional review often for a long-lasting relationship with your car; value for your money and less headache from frequent malfunction.

Click Here to Leave a Comment Below 0 comments