What Causes A Car To Overheat?

The normal operating temperature of most vehicles ranges from 195 to 225 degrees Fahrenheit. This particular range is very essential for proper performance in terms of the car’s fuel usage and the emissions control.

When problems arise and cause the engine to run hotter than normal, this is called overheating. These problems are mostly categorized by something preventing the coolant from absorbing, transporting or releasing of the heat to the atmosphere.

The major implication is that the coolant that regulates the vehicle’s temperature, which is a 1:1 mixture of ethylene glycol antifreeze and water, boils at 225 degrees. However, the radiator cap plays an important role in preventing the coolant from boiling and invariably, the engine from overheating by manipulating the coolant blend to a 70/30 ratio.

This process, using a 15 psi radiator cap, increases the boiling temperature of the coolant to 276 degrees. By so doing, the car gets back to its normal operating temperature.

Therefore, when neither the coolant nor the efforts of the radiator cap can keep the car’s temperature from going up, the engine simply overheats.



What Causes My Car To Overheat?

Given the condition that causes a car’s engine to overheat, you should know that there are quite a lot of reasons that could cause the engine’s temperature to increase without being regulated by the coolant.


Cooling System problems

Technically, this is the first check point in case your car overheats since the cooling system is majorly responsible for regulating the car’s temperature. However, there are a lot of other check points in this category and you might need to take your time with each of them.

  • Leakage : If there is a leakage in any part of the cooling system, (starting from the radiator, the water pump, head gasket, hoses or the thermostat housing), it won’t be effective. Therefore, if you can find the leak and plug it, or best, send it to the auto repair shop, then you’ll be just fine.


  • Blocked Hoses : Sometimes, the hoses may be blocked by sediments and other impurities from the road and prevent efficient transmission of the coolants to the engine. This can reduce the impact of the cooling system and cause the engine to overheat. The solution to this problem is to flush the entire system and refill the coolant tank.


  • Inauthentic coolant : If you use the wrong coolant for your engine, or even worse, if the coolant ratio is off (i.e., the ratio of water to ethylene glycol antifreeze, which should at most be 30:70), then your engine might not remain cool for long.


  • Faulty Radiator : As explained earlier, the radiator plays an important role in allowing heat to escape from the vehicle’s engine. When this occurs, it’s best to inform your auto mechanic about it.


  • Broken Water Pump : The water pump helps pump and propel the coolant from the reserve to your engine’s cooling system. If there’s an issue with the pump, the coolant can’t get to the cooling system. The major issues that cause the water pump to fail include leaks, eroded impeller vanes, as well as shifting in the pump shafts.

Other problems that could cause your car to overheat include;

  • Low coolant
  • Bad Electric Cooling Fan
  • Bad Fan Belt
  • Excessive back pressure in the exhaust
  • Bad Thermostat
  • Leaky Head Gasket
  • Plugged or dirty radiator
  • Engine overuse
  • Overheated incoming air
  • Slipping belt
  • Lack of Proper Maintenance


Every vehicle is susceptible to overheating especially after long hours of running. However, if you notice that your engine is overheating, the first aid is to turn on the heat in your car. This would help move the hot air out of the engine compartment while you make your way to your mechanic’s auto shop for proper diagnostics and fixing.

Leave a Comment