You are currently viewing Car overheating

Car overheating

Car overheating can cause because of many reasons. Most of the time engine over heating problem can cause when engine heat did not able to escape from engine compartment. To cool down engine heat a cooling system is installed in vehicle. Which consist of radiator, water pump, cooling fan, coolant, hose pipe, coolant temperature sensor and thermostat valve. Car overheating problem can be cause due to multiple reasons like low coolant level, failure of cooling fan, damage water pump, leak hose pipe and faulty temperature sensor.

Engine cooling system function:

Engine cooling system have a coolant tank in which coolant fluid is store. Some amount of coolant fluid get enter into engine block. A radiator is installed at front of engine from where engine coolant recirculate to cool down its temperature. An electric fan is also located behind the radiator which help in cooling the temperature of coolant.

Coolant temperature sensor is located the elbow of thermostat valve and monitor the temperature of coolant. When coolant present in the block of engine reach the temperature above 90-90 degree celcius thermostat valve open and coolant start circulation. Coolant temperature sensor sens the heat of coolant and send this signal to engine control module. According to which engine control module send signal to electric fan. So that electric fan turn ON and cool down the circulating coolant through radiator. A coolant pump is present in the engine which helps the coolant to recirculate in engine with require force.

Causes of car overheating:

  • Failure of engine coolant temperature sensor.
  • Faulty electric fan control module.
  • Low level of coolant in the coolant tank.
  • Damage fins of coolant water pump.
  • Leak hose pipe.
  • Leak or damage radiator.
  • Faulty thermostat valve.

Car overheating can cause due to following reasons:

Low level of coolant: Coolant is antifreeze known as glycol diluted with water. It provide better engine cooling system in cold weather also. The main role of coolant is to maintain the temperature of combustion engine and save it from overheating. When coolant does not recirculate from radiator to combustion engine. Due to failure of water pump, leak or blockage or radiator it can cause engine overheating problem.

Faulty thermostat: Thermostat valve of engine is located in the water elbow. It allow coolant to flow through it when coolant heat reach the required level. The thermostat valve did not open and let the coolant flow through it when engine runs at idle or engine is cool.

When thermostat did not let the coolant flow through it. Even coolant temperature reach the required level. It can cause engine over heating problem. As when coolant will not flow through it and reach to the radiator. Heat coolant temperature will not change until it will not circulate through radiator.

 Failure of coolant temperature sensor:  Coolant temperature sensor is located at the body of thermostat valve. It monitors the temperature of coolant and send this signal to engine control module. Engine control module receive this signal and send signal to electric fan controller so that electric can turn ON. When engine coolant start recirculating through radiator.

Faulty coolant temperature sensor will not sent proper signal to engine control module. In result which engine control module will not send signal to electric fan to turn ON. When electric fan will not turn ON than temperature changing process of coolant will be to slow. Because of which engine overheating problem can be seen.

Faulty electric fan: Electric fan is located at behind radiator, which get turn ON when engine coolant start circulating through radiator. It helps the radiator to cool down the coolant temperature very fast.

When electric fan does not start due any reason like damage wiring harness, faulty temperature sensor, no signal to control module, failure of electric fan. The process of cooling the temperature of coolant will become too slow. In result which engine overheating problem will cause?

Leak or block radiator:  Engine coolant start flowing through radiator so that its temperature can be change. When radiator is leak or block it does not pass the coolant temperature through it as per the requirement. Due to which engine coolant will not reach to the combustion chamber at the require time. It can cause engine overheating problem and can cause the serious injury to engine.

Symptoms of car overheating:

  • Engine may not start.
  • Coolant temperature warning light will start flashing on cluster.
  • Engine may stall while driving due to overheating.
  • Air conditioning system may stop working.

How to trouble shoot:

When engine over heating problem cause in vehicle and running engine stall due to overheating. Than you should stop vehicle do not drive in engine over heating condition. Wait for a while until engine heat get escape from engine. Do not open coolant tank cap or touch any part of engine until engine temperature reach its normal temperature.

Now open hood of engine and check the coolant level in the coolant tank. If coolant is empty in coolant tank and there is no coolant present at the required level. Then slowly slowly open engine coolant tank cap so that if there is any gas left in the tank can come out easily. Fill the proper amount of coolant in the coolant tank.

Also check leakage of coolant from the hose pipe, radiator. If found any leakage over there than replace the leaky part of cooling system. After replacing faulty parts of the cooling system check if leakage is close or not. If leakage is close than take test drive so that it can confirm if leakage is close or not.

When there is no leakage of coolant at the cooling system and still engine get overheat. It means that there is some other problem at cooling system. Like water pump which is use to make pressure to circulate coolant fluid did not make enough pressure to circulate coolant fluid. In this situation you need to remove water pump out side to check the condition of water pump. If its fins look damage, than it need to be replace.

Also check electrical system of cooling system (coolant temperature sensor, electric fan, thermostat valve). When coolant present in the engine block get heat, thermostat valve open and coolant start circulating through radiator to water pump. Coolant temperature sensor located on the water elbow sense the temperature of coolant and send this signal to engine control module. Engine control module receive this signal and send signal to electric fan to turn ON. Cooling fan turn ON and cool down the coolant fluid which is circulating through radiator.

If fault code is store in control module indicate problem toward coolant temperature sensor. Than you need to check wiring harness of the sensor, if found damage wiring harness than repair that. If coolant temperature sensor is fail than change coolant temperature sensor.

If coolant temperature sensor is working and sending signal of about coolant temperature to engine control module. When engine control module send signal to electric fan. But electric fan does not turn ON, it means that there is some problem occurs at electric engine. Check problem at electrical fan if found damage wiring harness, blown fuse, faulty relay than replace or replace them. Check electrical fan, if electrical fan have any problem than replace electrical fan.


Replace faulty engine coolant temperature sensor.

Repair or replace electric fan control module.

Fill proper level of coolant in the coolant tank.

Replace faulty water pump.

Close leak hose pipe.

Repair or replace leak or damage radiator.

Replace faulty thermostat valve.

How risky it is to drive with car overheating:

Driving with the problem of engine overheating can cause major problem with engine. it can cause engine internal problem like blown gasket, piston ring damage. That’s why do not drive vehicle with the problem of engine overheating. First fix the issue of engine over heating than derive vehicle. So that it can save engine major mechanical problem.

Common mistake while solving car overheating:

Solving engine overheating problem is not an easy job. Most the time engine overheating problem occurs when engine coolant did not circulate properly. In this situation you need to check the reason behind no circulation of engine coolant. Mechanic need to check thermostat valve and radiator because this is the only two reason due to which engine coolant did not circulate properly. But instant of checking these two things mechanic did change thermostat valve. Which might be good sometime but not all time.

Precausion need to care while solving:

While driving vehicle for long time keep watching engine temperature measuring gauge. That temperature gauge show the temperature of engine compartment.  This temperature gauge should not go above 90-95 degree Celsius. If it go above 90-95 degree Celsius than it means that car engine is overheating. In this situation switch off the engine and do not drive for a short time of period. Wait for some time until engine heat escape from engine compartment. Open hood of engine compartment and first of all check the coolant level in coolant storage tank visually. Do not open coolant tank cap as there may be gas inside the coolant tank due to which water will flow out in pressure when cap will open.

When car engine heat completely escape from engine compartment than start inspecting the reason behind car overheating. In case of opening any part which is related with engine cooling system first check temperature of engine than open any part.

Always use proper coolant as per the manufacturer advice as there are many types of coolants are present in the market like red, green, blue etc. If manufacturer advice to use of red color coolant than use only red color coolant. Because if you will use any other brand of coolant it can damage the entire system of engine cooling.

Leave a Reply