Why Does My Car Overheat

Why Does My Car Overheat? 7 of the Most Common Causes

Welcome back car enthusiasts, today we are going to talk about some common causes of an overheated engine so that you can practice prevention and avoid the side of the road.Why Does My Car Overheat

Here we are tackling the question:  “Why Does My Car Overheat?”

The scenario usually goes something like this…

There you are, cruising down the street, watching fumes evaporate from the sweltering streets as acrid air from the heater you had to turn on to help keep the engine cool, pours from the vents and out of the wide open windows.

You nervously check the heating gauge and feel your chest tense just a little more as the dial bounces on the border of making it home and having to call a tow truck.

Then you see it, the dreaded stop light, and the long line of cars waiting behind it. It’s almost inevitable now, your car is probably going to overheat.

Related10 Essential Summer Car Maintenance Tips

7 of the Most Common Car Overheating Causes

1. Someone Forgot to Check the Coolant or Somethings Leaking

Coolant, which is also known as Antifreeze, is a half and half mixture of water and ethylene that is used in engines to make the freezing points of water-based liquids colder and their boiling points higher.

Low levels of coolant can be due to leaks in the cooling system hoses that allows the antifreeze to flow into the engine. Check out this video “How to Find Cooling System Leaks” which will show you how to find and repair the damage.

Another cause of leaks is the lack of maintenance or improper maintenance.

To help you make sure your antifreeze levels are at an appropriate level watch, “Checking Coolant or Antifreeze for Beginners” and be sure to routinely check your coolant levels with every oil change and before any long road trips.

2. The Engine Needs More Air from the Radiator Fan:

The Cooling or Radiator fan is located in front of, or sometimes in back of the radiator so that it can blow cool air onto the radiator.

The air keeps the temperature of the engine low which keeps the engine happy. To learn more about radiator fans “How Does a Radiator Fan Work” is a good post.

Radiator fan replacements tend to be complex, so you may choose to take it to a professional.


If you fancy yourself as engine savvy, or a natural DIY’er, check out “5 common Radiator Fan Problems” from doityourself.com.

3. The Thermostat Won’t Let the Antifreeze Through:

A thermostat has two main functions, first to keep coolant from getting to the system when it’s cold and second, the thermostat opens a chamber which lets the coolant get to the system to make sure the engine doesn’t get to hot.

It does this by monitoring the temperature of the engine and then opening once the engine gets to around 200 degrees, 95 degrees fahrenheit.

Here’s a video with a detailed explanation of how thermostats work . Typically when the thermostat in your engine has gone bad, the car will run fine for a few minutes and then have a dramatic spike in temperature.

Related: Why Do Cars Depreciate So Quickly?

How To Know if a Thermostat is faulty?

4. There’s a Belt(s) or Chain That Needs to Be Checked or Replaced:

There are two types of belts that need to be checked.Why Does My Car Overheat

Timing Belt and Chains:

The purpose of the timing belt, chain, or gears is to turn the camshaft in your engine in time with the crankshaft.

This allows the camshaft to open and close valves in perfect time so that the engine performs at it’s highest level. Here’s a great video from AutoZone called, “What is a Timing Belt”.

Water Pump Accessory Belt or Serpentine Belt:

A serpentine belt is a long single belt used to drive the water pump among many other components. The water pump is imperative to keeping the engine cool and running properly.

Typically you can tell if you have a belt problem before you even lift the hood because there will be an annoying squeak every time your engine runs.

These belts are usually checked and replaced with routine tune-ups and when done consistently rarely cause problems unless they were installed too loose or too tight.

How to Check if your Drive/Serpentine Belt Needs Replacing.

5. The Radiator isn’t Working Properly:

The main purpose of a radiator is to act as a heat exchanger and transfer heat through thin fins that are brazed to flattened tubes.

Most radiator are made from aluminum and through normal wear and tear can form cracks which allows coolant and water to seep through causing a leak.

When you see steam pouring from the engine, it’s coming from the fluids inside the radiator.

Remember, an engine is overheating because it is HOT so wait until the engine cools before touching anything.

Related: How To Clean Your Car Engine

6. The Water Pump Isn’t Pumping:

As we learned earlier, the water pumps keep the coolant circulating between the radiator and the engine.

It is arguably the heart of the cooling system because it keeps all the proper liquids flowing. When the water pump fails coolant stays pooled in it’s tank and the engine temperature climbs up until it overheats.

To diagnose your water pump and find out if it’s causing the overheating in your vehicle check out “Symptoms of a Bad or Failing Water Pump”

7. Ignoring the Low Oil Light:

This last one may seem like a no brainer, but overheating due to lack of oil happens more times then you think.

Oil lubricates all the rumbling, mashing and smashing parts of your engine that allows combustion to power the engine to run.

Without oil these same parts begin to cause friction that heats the engine to dangerous levels. There is no amount of coolant that will stop the destruction that a lack of oil can cause.

How to Check Your Oil Levels


Overheating always seems to happen at the worst time in the worst possible place. The good news is that armed with a little knowledge, an overheating car can become a rare occurrence. The biggest tip would be to make sure to keep your car running well.

Whether you do it yourself or have someone else do it, make sure to take just a little extra time to be thorough and you’ll be sure to save yourself a lot of heartache and sweat.

Thanks for reading and be sure to leave your questions and comments below and tell me if this knowledge has helped. Until next time.

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