Why is my car engine hot but not overheating?

This blog post will answer the question, ‘Why is my car engine hot but not overheating?’, and cover topics like reasons behind a car engine being hot but not overheating, different temperature gauge conditions, and what to do in case of a car engine being hot but not overheating.

Why is my car engine hot but not overheating?

These are the following reasons why the car engine is hot but not overheating:

  • A clogged radiator
  • Damaged water pump
  • Excessive load on the engine 
  • Faulty thermostat
  • Insufficient coolant level 

Reasons behind a car engine being hot but not overheating

These are the following reasons behind a car engine being hot but not overheated.

Faulty ECT

An ECT, also known as the engine coolant temperature sensor, helps to monitor the temperature of the coolant and thus regulate the temperature of the engine.

In case of a faulty ECT, the signal sent to the electronic control unit(ECU) is erroneous and can lead to the ECU not turning on the cooling systems as the ECT does not say if the engine is hot/cold. This can cause severe overheating of the engine.

Failing head gasket

A failing head gasket results in the leakage of the coolant and water mixture onto the other parts of the engine like the radiator. This results in the formation of fumes from under the radiator as the gases have no escape route from the cylinders.

Insufficient coolant level

It is common for the temperature gauge of a car to signal an overheating engine, due to an insufficient coolant supply. It is necessary to keep tabs on the coolant levels in a car engine.

The coolant levels must be changed when necessary and in some cases, flushing the radiator can also be done to drain out the old coolant.

Defective water pump

A defective or failing water pump results in decreased car efficiency and overheating. A failing water pump is usually caused due to clogged pathways that prevent the flow of water.

Faulty temperature gauge

In case the temperature gauge is broken or faulty, it will never display the correct temperature of the engine, and cause it to overheat as we will never realize when the engine needs cooling.

Faults in the thermostat

The thermostat is a very important component in a car engine as it helps regulate the coolant flow to the car engine as per requirements. If there is a fault in the thermostat, the coolant might be sent too early or too late, resulting in overheating of the engine.

Defective cooling fan

A broken cooling fan or a fan whose blades are stuck, offers more resistance and lesser airflow, thus preventing the optimum cooling necessary for an engine.

Defective radiator cap

The radiator cap is responsible for regulating the pressure of the coolant. A defective radiator cap will result in coolant overflow and in extreme cases, even an explosion.

Different temperature gauge conditions

These are some different temperature gauge conditions.

A fluctuating temperature gauge

These are the following factors affecting a fluctuating temperature gauge:

  •  A damaged or broken thermostat needs to be replaced immediately
  • A defective radiator is another factor and is indicated by unusual noises
  • A damaged head gasket is indicated by cracks on its surface and results in the leakage of the coolant into the engine

The temperature gauge reads high

The factors affecting a high-temperature reading are:

  • An overheating engine
  • Leakage of coolant
  • Faulty thermostat
  • Defective water pump

The temperature gauge reads low

A temperature gauge under normal working conditions can only read low when the engine is turned off. If it reads low even while the engine is running or the car is in motion, and fumes appear from the engine, the temperature gauge itself needs a replacement.

What to do in case of a car engine is hot but not overheated?

These are the following steps to follow in case of a car engine being hot but not overheating.

  • In such a situation, the car must be parked at the side and allowed to cool off. This helps in bringing the car down to a normal operating temperature. It is important to keep tabs on the car temperature gauge all the time
  • If the previous step is farfetched, all electrical components can be turned off and the heater can be switched on. Turning the heater on will help suck out all the hot air from the engine into the vehicle and help the engine achieve normal temperatures.
  • Another important thing to do is to check the engine coolant level. It is necessary to refill the coolant if needed or to drain out the radiator in case of the coolant gets too old. Insufficient coolant levels can cause severe engine overheating.
  • There are cost-effective radiator cooling blends available that can be used as a strong alternative to the above-mentioned steps.
  • After the engine has cooled off or has reached a normal operating temperature, the engine should be started and the temperature gauge should be checked for further heating.

Research has shown the different types of coolants and the various factors that need to be taken into consideration when selecting the best engine coolant for your car.

Other articles about Mercedes Benz you may be interested in

What causes a car engine to misfire?

How to avoid a blown car engine?

What are the reasons behind my car engine sputtering when starting?


This blog post addressed the question, ‘Why is my car engine hot but not overheating?’

We understood the different reasons behind a car engine turning hot without overheating, and also came across the different temperature gauge conditions. Furthermore, the various steps to be taken in case of a car engine running hot but not overheating have also been discussed. Please feel free to comment on the content or ask any questions in the comments section below.

Frequently Asked Questions (FAQs): Why is my car engine hot but not overheating?

Why does my engine feel so hot?

The primary reasons behind a car engine feeling hot are a defective water pump, damaged head gasket, a faulty thermostat, or, insufficient coolant levels.

What are the signs of a clogged radiator?

Telltale signs of a clogged radiator are:

  • The texture of the coolant appears thicker than usual
  • Leakage of coolant
  • The temperature gauge reads abnormally high readings
  • Damaged radiator cooling fins

How do I know if my water pump is bad?

These are the following signs behind a water pump being bad:

  • Formation of steam from the radiator
  • Weird noises
  • Deposition of rust
  • Excessive overheating