What Causes A Car To Overheat ?

Many car owners have stressed at the inevitable problem that we all encounter: overheating. You have probably experienced it and want answers as to why it happens and how to prevent it. From leaking hoses, failing engine cooling systems and broken fan belts, let us take a look at the possible answers as to what causes a car to overheat.

Your car’s cooling fan has stopped working

One of the most common reasons why a car overheats according to Dummies is the cooling fan ceasing to fulfill its sole purpose. Although pretty easy to spot, this actually is overlooked by many car owners simply because it feels too obvious and most folks try to look for complicated reasons first. You should be able to locate the fan close to the radiator. There, you have to make sure that the fan is not slow or not working at all. If it is either of the two, then that means:

  • 1. The electric fan has become faulty.

In this case, you can always turn on the air conditioning so you can see if the fan will turn on as well. Most of the time, this will force the fan to begin working again.

If this does not work, then you can remove the harness for the wiring of your radiator fan switch. Insert a jumper wire then check the fan’s condition again.

Either way, this means that the motor of your fan has already burned out so you will need to buy a new one.

  • 2. The radiator switch has become faulty.

For your car’s cooling fan to switch on, the radiator must read a certain point of your temperature reached. The problem is if this component is faulty, then it will not be able to properly dictate when to turn on the cooling fan.

To check if this is the case, simply follow the steps above, but make sure to stop right after you attach the jumper wire. If the fan comes on instantly, then that means you need a new switch for your radiator.

Your car’s coolant has become too low

ASC Industries have conducted a study on the common causes of overheating when it comes to cars. They found out that one of the main reasons is the coolant concentration being wrong or low.

If this is the case for your car, then you will get a warning light (maintenance needed) that notifies you on the dashboard. If the coolant is already at an incredibly low level, then you might not even get anything at all. As soon as your car engine overheats, this should be one of the first things that you check.

Take a look at your car’s coolant level and see if you need more. If you need professional advice, then go ahead and seek help from your local mechanic. They will most likely not charge for such a simple check especially if they are a family owned business.

Having an ample coolant is extremely important for your car’s engine. It ensures that everything is cooled down and adapts to different situations. Whether you are driving in the middle of heavy traffic or speeding through the highway, your coolant is the one maintaining the coolness of your entire ride.

Your car’s fan belt broke

The very first time I encountered an overheating engine, I found out how important a fan belt is. When might broke, the car overheated fairly quickly and I found out that some other components of my vehicle need to be replaced. A broken fan belt is a good indicator that the other parts of your engine are not in good condition.

If you own an older car, then you are in luck since fan belts are a lot more common for those. You will not need to shell out too much money to get it fixed and finding out if you even need to is easy since you just need to take a quick look at your engine.

Your car’s thermostat remains closed

Your car’s thermostat should track the car’s temperature as soon as it starts to heat up. When that temperature hits a certain point, your car’s thermostat will open and allow more coolant to flow into it to cool the engine. This is why your thermostat remaining closed is a possibly culprit to the vehicle overheating.

Make sure that your car does not think that it is still idle by having your car’s thermostat checked by a specialist. A video guide by expertvillage shows you the step by step process on finding out whether your car’s thermostat is faulty.

Your radiator needs to be flushed

Though not a common occurrence, a clogged up radiator is the result of having more than 50,000 miles on your vehicle. You will most likely find a lot of gunk that prevents the radiator from functioning as it was intended to. Make sure that you have your car’s radiator flushed every year. It does not take too long and it helps keep you from even more headaches in the long run.

You have a leaking coolant

Having a leaking coolant will definitely be obvious since your car will overheat whether you are driving or you are parked. It is easy to check if this is the case since you only have to step out of your vehicle and look underneath it for any traces of abnormal amounts of fluid flowing out or forming a puddle. If that is the case, then you have just confirmed a coolant leak.

After confirming the coolant leak, you can confirm it by monitoring the coolant levels. If you see that they are low even if you fill it up recently, then that further leads you to the cause of the overheat. Go to your preferred service station and have this patched up as soon as possible. Make sure that you fill it up right after.

What happens when my car overheats?


Depending on the vehicle, there are a lot of things that can happen if your engine has started to overheat. Of course, I do not suggest finding out for yourself, but here are the most common incidents that occur right after an overheated engine went unnoticed:

  • Engine starts to detonate and rattle
  • Engine begins to lose power
  • Detonation causes a great deal of damage to the pistons, rings and rod bearings
  • Exhaust valves gets damaged along with the valves

If your car has already started to overheat, we highly suggest that you follow Safety Serve’s guide. It keeps you from any possible harm while you wait for your vehicle to be serviced.


As you can see, it is not worth risking you and your vehicle’s well being. Get your car serviced as soon as possible and refrain from even turning on the engine when you know it will start to overheat thereafter. I hope that this guide helped you find the cause of your overheating car engine.

Make sure to tell your friends about this, so they will be safe from a potential accident themselves. Do not forget to leave a comment and even share a thing or two that you might know about engines and what causes a car to overheat. As always, stay safe on the road!

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