Engine overheating: causes and solutions

The causes of engine overheating can be different. It should be understood that if the engine overheats, the causes of this should be eliminated as soon as possible, otherwise it can lead to irreparable consequences. In the case of severe overheating of the engine, it will knock or even jam. Important parts of the cylinder-piston group can be affected. Pistons can melt and burn through to complete destruction. Engine oil heats up to a temperature at which its lubricating properties become like water. As a result, the oil will no longer lubricate and protect engine parts. Usually when the engine overheats, the cylinder head plane warps and cracks occur. It is not uncommon for the head gasket to burn through.

How to know that the engine overheated?

It is necessary to periodically monitor the temperature of the power unit. If the indicator is in the “red” zone, then you should check the condition of the motor. If the power unit is in a state of overheating, you can smell the coolant, which is already “boiling”. Also from the hood of the car can go steam. Detonation will be heard in the engine – abnormal combustion of fuel. In this case, it is best to stop the car and deal with the problem. Otherwise, in just a few minutes, the condition may already be critical.

Causes of overheating. Contamination of the surface of the cooling radiator

If the car engine overheats, pay attention to the condition of the main radiator and air conditioner radiator, and more precisely whether they are clogged with insects, road dust, and especially poplar fluff, which in spring and summer is the main cause of this problem. A lot of dirt, dust and fluff collects in the space between radiators. In order to avoid this, it is necessary to do preventive maintenance by cleaning the radiator periodically. The radiator surface can be cleaned either by water jet or by compressed air.

Pollution of radiator channels

Radiator, or rather its honeycomb or channels, can be clogged with dirt and inside. Pay attention to what coolant you put in the radiator. If it is not compatible with the one that is already poured in, you cannot avoid engine overheating. Incompatibility of coolants, as a rule, leads to the formation of sediments that clog the radiator. In this case there is only one solution to the problem – flushing the radiator.

Cooling fan malfunction

A common cause of engine overheating is untimely inclusion of the fan. But before the fan is sentenced to replacement, it is necessary to make sure that its sensor is in good working order. Contamination of the part of the radiator where the sensor itself is located leads to the fact that the heat transfer from the coolant to the sensor itself will be delayed. As a result, the fan will be switched on with delay. Not infrequent cases of banal failure of the fan sensor. In addition, the electric fan motor can simply stop working because of a blown fuse, wear of the motor brushes or burning of its winding.

Malfunction of the pump

Engine overheating: causes and solutions

The water pump (water pump) of the engine cooling system is an important component that provides constant circulation of coolant through the channels of the cooling jacket, pipes, trunk lines, cooling radiator, etc. Even a slight decrease in the performance of the car pump can cause overheating of the engine, especially in the warm season. Usually the pump is changed together with the timing belt, from which its impeller is driven.

Few cars have a plastic impeller on the pump, and over time it can turn. The result: poor circulation of fluid, no longer coping with its function.

Thermostat malfunction

The thermostat is one of the elements that regulate the temperature of the coolant circulating in the cooling system circuits. When a completely cold engine is started, the thermostat valve is fully closed. This allows the fluid to circulate only through the small cooling circuit, which allows the engine to warm up more quickly. However, as soon as the coolant temperature reaches above 80°C, the thermostat valve will automatically open. This allows the fluid to flow to the main radiator, where it can cool down and maintain the normal operating temperature of the engine. In case of thermostat malfunction, its valve opens too early (in this case, the coolant and engine do not warm up to operating temperature) or too late (in this case, the engine overheats).

The thermostat valve may not open at all, as a result of which the coolant will not circulate in a large, but in a small circle (bypassing the radiator) and, accordingly, it will not be cooled. Faulty thermostat can be determined by gently feeling the lower part of the radiator of the car when the engine is hot. If it is cool, it is the thermostat that is to blame for engine overheating. The thermostat is not repairable, but must always be replaced with a new one.

Lack of pressure inside the engine cooling system

To create a higher-than-atmospheric pressure in the cooling system, a special expansion tank cap has been provided, which keeps the right pressure in the system. A special valve that is built into the cap relieves too much pressure, but also prevents the pressure inside the system from matching the atmospheric pressure.

Engine overheating: causes and solutions

Important point: if the valve in the expansion tank lid is not working properly and does not hold the increased pressure, the coolant begins to boil earlier, begins to splash, air plugs are formed, and this leads to low efficiency of the entire cooling system. Such a fluid is very poorly removes heat from the engine.

Also if the valve does not let air into the cooling system, then when the coolant cools down, it decreases in volume. A vacuum is formed, which can be filled with the same air, which, in turn, can penetrate the system through unsealed connections, and this will lead to the formation of the same air plugs. Engine overheating in this case is inevitable. As a rule, this problem is solved by simply replacing the expansion tank plug. But do not forget to expel the air plug from the cooling system.

Combustion chamber seal failure

Usually a consequence of previous overheating, when head gaskets burn out, cracks appear in the cylinder head and liner, deformation of the cylinder head or block. Determine this cause can be determined by the coolant leaking from the barrel, a rapid increase in pressure in the cooling system immediately after startup, as well as the characteristic water-oil emulsion in the crankcase. But it is usually only possible to establish exactly what the leaks are connected with after partial disassembly of the engine.

Coolant leakage

Clear leaks in the cooling system occur most often due to cracks in the hoses, loose tightening of clamps, wear of the pump seal, malfunction of the heater valve, radiator and other reasons. This can occur due to the use of poor-quality coolants, sudden changes in ambient temperatures, forcing water obstacles.

Cooling system suffocation

A cylinder head gasket can also affect the air in the cooling system. Usually, if the gasket is punctured, antifreeze leakage is visible. But the leakage can be noticed not at once. If the cause of engine overheating could not be immediately identified, then pay attention to this point.

Dirty engine

Engine overheating: causes and solutions

A dirty engine gives off heat to the atmosphere worse, which can lead to a slight overheating of the engine. Therefore, do not forget to periodically wash the engine of your car.

Engine overheating: causes and solutions.

Cause Description Solutions
Dirty radiator The radiator may be clogged with dirt, dust, insects or poplar fluff, which impairs its cooling properties. Clean the radiator regularly with a water jet or compressed air.
Dirty radiator channels Incompatible coolants can cause sediment that clogs radiator honeycombs. Radiator flushing and the use of compatible coolants.
Fan malfunction The fan may not turn on in time due to a faulty sensor or electric motor failure. Check and replace the sensor, fuse, fan motor.
Pump malfunction Decreased performance of the water pump (pump) leads to insufficient coolant circulation. Replacement of the pump, often together with the timing belt.
Thermostat malfunction The thermostat may not open in time, which leads to overheating due to insufficient coolant circulation. Replacing the thermostat when it malfunctions.
Lack of pressure in the system A defective expansion tank cap valve does not create the necessary pressure, which leads to boiling of coolant and the formation of air plugs. Replace the expansion tank cap and remove air locks from the cooling system.
Combustion chamber seal failure Gasket deterioration, cracks in the cylinder head, deformation of the block can lead to gas leaks and overheating. Partial engine disassembly, gasket replacement and cylinder head repair.
Coolant Leakage System leaks due to cracked hoses, loose clamps, or a faulty heater valve can cause coolant leaks. Replace damaged hoses, clamps and other cooling system components.
System air plugs Air plugs can occur due to leaks or improperly installed cylinder head gasket. Remove air plugs, check and replace the cylinder head gasket.
Dirty engine Dirt on the engine impairs its heat dissipation, which can lead to minor overheating. Regularly wash the engine to improve heat transfer.

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