The most common problem in internal combustion engines is excessive overheating. There are several causes and factors for this phenomenon, some objective and logical, others sudden and unusual. These are as follows:
Water Pump
The water pump in the engine is responsible for circulating coolant in the engine to cool it, then returning it to the radiator to lower the coolant temperature. After this process is repeated, if the pump is worn and not rotating properly, this will cause the engine to overheat.
You can determine whether the pump is working properly by starting the engine, opening the water tank cap, observing the coolant flow, and comparing it to another car of the same make. If you find a difference, this indicates the beginning of pump failure or a blockage in the hoses or engine.
Most modern car manufacturers recommend replacing the water pump when replacing the timing belt. This is especially important since the materials used to manufacture water pumps have changed significantly.
Thermoplastic is now part of the pump, and this material has a limited and unpredictable lifespan. Even if the pump is in good condition, it’s best to replace it, as it won’t last and will fail at any moment.
Thermostat
When the thermostat fails, it remains closed, preventing coolant from circulating inside the engine. This causes an increase in temperature. You can determine whether the thermostat is the cause by examining the coolant hoses. If they are bulging and there is a significant temperature difference between them, this is strong evidence of a faulty thermostat.
A faulty thermostat is usually accompanied by constant ignition of the cooling fans, even in the morning. There are many types of thermostats, some of which are standard, while others are controlled by the car’s computer.
Radiator
A clogged radiator prevents it from functioning properly. It’s best to clean and clear it of dirt and deposits inside and out, and change the coolant regularly.
A dirty radiator filled with grease and oils can easily collect dust. This reduces cooling efficiency and is a direct cause of engine overheating.
Cylinder Head Gasket
A damaged engine head gasket is one of the most common causes of engine overheating. You can check the engine head gasket by opening the coolant tank or radiator cap and checking for air bubbles in the water.
A damaged engine head gasket is often accompanied by combustion problems and difficulty starting. However, these aren’t always the symptoms of a damaged cylinder head, as engines vary in power, torque, and the number of cylinders they have.
Cooling Fans
The fans operate at a specific temperature set by the vehicle manufacturer to lower engine temperature. Any delay in operation, or a partial or complete shutdown, will slow the coolant cooling process, which in turn will cause the engine temperature to rise.
The fans can be checked by starting the car and letting them run until the engine temperature exceeds the normal temperature. If the fans do not operate, this indicates a defect in the fans or the start sensor.
The temperature sensor should also be checked, as it is another cause of delayed cooling fan ignition.
Radiator Cap and Water Tank Cap
The radiator cap and water tank cap are pressure valves that balance the pressure inside the cooling system with the external pressure. They allow a specific amount of coolant to escape to avoid damage to the engine head gasket.
They also prevent air from leaking into the cooling system, as this would increase engine temperature.
The radiator cap and water tank have a specific pressure limit determined by the vehicle manufacturer. This pressure is printed on the cap. A cap must be installed with the same pressure it can withstand, as replacing it will cause a malfunction in the cooling cycle.
Temperature Sensor
A damaged temperature sensor doesn’t raise engine temperature, but it gives an incorrect reading to the fans and the car’s computer. It’s a long-lasting component and rarely breaks down.
The sensor is usually dirty due to the buildup of limescale and mineral deposits, so it must be removed and cleaned.
There are a number of reasons why an engine can overheat, such as a punctured hose, worn engine side covers, or a broken water pump drive belt. However, these can be noticed when the engine is stopped, allowing you to detect the problem.
