how hot is a car engine?

In this brief article, we understand how hot a car engine is.We also analyse how to identify whether the car engine is running at optimal temperature and also analyse the probelm of cold staring and overheating.

How hot is a car engine?

Car engines are mechanical devices that convert the chemical energy present in the fuel to useful mechanical work.They do so by burning the fuel in a combustion chamber.This process produces heat.Car engines operate at an optimum range of temperature  which is generally between 170-200 degree celsius. Overheating of the car engine can be undesirable and thus a cooling system is provided.

What causes a car engine to heat up?

Car engines are technically Internal Combustion(I.C) engines and run on a certain thermodynamic cycle.They intake fuel and burn it in order to produce useful work.THe process of burning the fuel(also known as combustion) during the power-stroke of the piston releases immense amount of energy in the form of heat.This heat needs to be released so as to maintain an optimal engine performance.This is the reason why car engines are provided with elaborate system to dissipate the excess heat into the environment.

How is the engine temperature maintained at the optimal level?

Most modern cars are equipped with a thermostat.The role of the thermostat is to maintain the temperature of the engine.It allows the flow of the coolant to the engine only after the car engine has reached a particular temperature. In other words, the engine is allowed to get hot enough before the coolant is supplied. Alas,cooling the engine when it is not hot enough to perform optimally is a wasteful prospect.

The thermostat thus has the job of the balancing regulator.When the engine is at a higher temperature, it activates the  flow of the coolant.

How to identify the engine temperature?

Most modern vehicles are equipped with a gauge on the dashboard.It indicates the temperature of the coolant that circulates within the engine.The gauge has two extremes Hot(H) and Cold(C). Generally the needle would position itself somewhere between these two extremes indicating the temperature of the coolant.This acts as proxy for the engine temperature and as an early warning mechanism of an overheating problem.

Cold starting a car engine?

Cold starting refers to the process of starting the vehicle when the engine temperature is too low.This is normally due to the prevailing weather conditions.Cold starting requires greater effort than regular starting as ignition is difficult, air density is high which affects the air-fuel mixture. Thus cold starting creates a greater pressure on the engine and results in increased wear and tear.

How hot is too hot for the car engine?

Engine heat also fluctuates depending on some conditions. Running the Air Conditioning system in full blast, Towing another car and even stop-start driving in high traffic on a hot day can cause the engine to temporarily overheat.In such cases, normalcy can be restored by pulling over the car and allowing it to cool.However, when the overheating is persistent and recurring, it is a cause for concern.

What causes car engines to overheat?

The car engine releases tremendous amounts of heat that needs to be released into the air.However, overheating can result in suboptimal performance of the engine,thus reducing efficiency and output. Some of the major reasons for overheating of the car engine are:

1.Inadequate coolant
2.Broken or faulty radiator
3.Damaged thermostat
4.Inadequate lubrication
5.Broken hoses
6.Damaged water pump

How to maintain the correct temperature of the car engine?

The optimal temperature of most car engines range between 170-200 degree celsius.Overheating occurs when this range is breached to high temperatures that become intolerable for the parts to function in the intended manner
There are a few things that you can do to ensure that your cat engine is hot enough to operate optimally and does not overheat.They are
1. Regular vehicle service and maintenance
2. Timely top up of the coolant 

3. Check for cracks and leaks in hoses, water pump etc

4. Not overloading the engine with heavy towing, full blast A/c etc

5. Avoiding Stop-Start driving. 

What to do when the car engine becomes too hot?

Temporary changes in the engine temperature due to towing or full blast A/C is not a serious cause of concern.The normalcy is restored as soon the load is removed.

However, if the overheating is persistent, then necessary steps have to be taken to get it resolved.Identifying the problem at an early stage is crucial to repair it.The problem of overheating can lead to a high repair cost if it is neglected.Thus it is imperative to nip the problem in the bud. Any abnormality in the temperature gauge should be reported and a thorough diagnostics of the engine and the cooling system needs to be performed.This  serves to limit the damage of the engine.However if the situation is out of hand and there are visible indications of overheating, such as steam/smoke coming out of the hood, then getting the engine and the cooling system checked by an authorised mechanic is the way to go.

Frequently Asked Question:How hot is a car engine?

1.What is the temperature of a car engine?

The optimal temperature of a car engine varies from around 170-210 degree celsius.

2.Why does an engine heat up when it is running?

There are many reasons for engine to warm up.This includes the heat released from the combustion of fuel, friction between moving parts etc

3.How is the car engine cooled?

A cooling system is present in order to ensure that the engine does not overheat.It consists of a coolant flowing which removes the heat from the engine and releases it through a radiator.

4.Is overheating of the car engine bad?

Yes. An engine is designed to perform under an optimal range of temperature.Thus overheating can affect the performance of the engine.It can further lead to high repair costs.

5. What to do if my car engine is overheating?

Take your car to an authorised mechanic at the earliest.Overheating of the car engine should not be neglected.


Winkler, H., “Engine-Temperature Control Factors,” SAE Technical Paper 370136, 1937,

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