Warning Signs of an Overheated Car Engine

Warning Signs of an Overheated Car Engine

If you drive a car, you must know that overheating of the engine can lead to serious damage. Therefore, every driver must be aware of the causes of engine overheating and the consequences. It will also be very good if you can avoid overheating or minimize its effects if necessary.

There is also a misconception that the engine overheats only in summer. However, this is not true. It all depends on a specific malfunction in the cooling system. And therefore, the engine can “boil” even in the most severe frost. However, in the summer, the accumulated problems of the power unit most often make themselves felt, many of which cause overheating. You must choose a car rental company that maintains and service their vehicles regularly. In this blog, we intend to discuss what symptoms and signs indicate an engine overheating and what to look out for when driving.

Sensor Reading

The main indicators of engine overheating can be indirect or direct - temperature sensor readings. A coolant temperature sensor is found in almost every vehicle. If the sensor arrow approaches the red area on the dial, it could mean that the car engine is overheating.

Some vehicles lack such a sensor. However, this does not imply that diagnosing engine overheating will be difficult. A blue (or, in some cases, green) light on the dashboard of such vehicles indicates the operating temperature. If the light turns red, it indicates that the engine temperature has reached an emergency level.


You will notice very loud metallic sounds, ringing, coming from under the hood. The engine itself starts to work "hard" and becomes noisy.  Such changes occur as a result of the engine detonation that appears when the combustion of fuel in the cylinders becomes explosive.

Spark Plugs

You can also determine overheating by spark plugs. As a rule, a significant increase in temperature in the combustion chamber is indicated by a white coating on the electrodes. Signs of engine overheating, which can be determined during the inspection, are darkening on the walls of the tank (gray-black spots). Additionally, you should look at the antifreeze itself. If dark-colored flakes in the coolant are noticeable, then this is oil that has entered the cooling system due to overheating.

Performance Drop

The car's power and traction drop immensely due to engine overheating. If the weather is warm outside, you are stuck in a traffic jam, or you are driving very slowly, but at the same time, you feel that the radiator fan does not turn off at all.

Steam Under the Hood

Signs of engine overheating can be seen from the steam that escapes from under the caps of the expansion tank or from the expanded pipes of the cooling system. Inside the cooling system, the temperature of the coolant rises, and in the wake of it, the pressure causes the nozzles to swell.