engine overheating symptoms
The first cars had an air cooling system - their motors were cooled by outboard air flows - today this can be seen in mopeds, chainsaws and other similar mechanisms. But the vast majority of modern equipment (not only cars, but also locomotives, tractors, combines) is equipped with a liquid engine cooling system. It is present even in electric vehicles and parts of motorcycles.
The advantages of liquid cooling (sometimes, in the old fashioned way, called water) are obvious:
uniform cooling of all engine components and, if necessary, other units;
low noise level (water jacket acts as sound insulation);
the possibility of selecting a coolant for heating the passenger compartment / cabin;
more correct engine heating control system.
The latter quality is especially important - both for the correct operation of automotive electronics, and for the engine resource in general. But, despite the obvious advantages, the liquid cooling system also has disadvantages, the main of which are the complexity and the presence of many components and parts that require care and control.
COOLING SYSTEM FAULTS LEADING TO OVERHEATING
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Speaking of malfunctions leading to excessive heating of the engine, two groups of malfunctions must be distinguished:
contributing to a decrease in the level of coolant;
preventing the normal circulation of coolant through the system.
Antifreezes are predominantly used in liquid cooling systems of automobiles today. These liquids, although they are about half water, have a lower freezing point and a higher boiling point. Antifreeze is less susceptible to evaporation, so leaks are the main reason for a decrease in its level in the system. Coolant leaks can be caused by:
damage to pipes / hoses through which coolant flows;
loose clamps;
loose fit of the system elements;
violation of the elasticity of seals (oil seals, gaskets;
mechanical damage to the elements of the cooling system: radiator tubes (including the heater), expansion tank, cylinder head gasket, jackets in the cylinder block.
In violation of the patency of the fluid through the system, the following are most often to blame:
Pump (water pump). The cessation of circulation due to the fault of the pump (or the breakage of the belt or chain that drives it) is very dangerous and quickly leads to overheating of the engine.
Thermostat. The cooling system of a car has two circuits. In a small circle (engine jacket, heater radiator, some attachments and inlet pipes), antifreeze circulates immediately after starting the engine until it warms up sufficiently. When the operating temperature is reached, the thermostat allows the coolant to enter the main cooling radiator, usually located at the front of the car. Untimely opening of the thermostat valve, as well as its malfunction, leads to incorrect temperature conditions. If the valve freezes in the open state - this is insufficient heating of the engine, in the closed state - overheating due to the impossibility of high-quality cooling of the liquid.
Clogging of the elements of the system - most often, the tubes of the main radiator or the interior heater radiator. Occurs due to the accumulation of deposits in narrow places: rust, dirt, antifreeze decomposition products.
In addition, insufficient cooling of the liquid caused by external clogging of the main radiator (when dirt, dust, insects get into the honeycombs), the air conditioner radiator, since it is usually located in front of the main one, and also the space between them.
Malfunctioning radiator fans also impair cooling, therefore, contribute to engine overheating.
HOW TO DETECT OVERHEATING
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The main sign indicating an engine overheating is the readings of the coolant sensors. Their data is sent both to the temperature gauge on the instrument panel and to the engine control unit. The driver needs to constantly monitor the thermometer: when the temperature rises, the arrow rises. Its average position is normal, approaching the red zone should alert, moving into the red zone should be a signal to take action. Some vehicles have an engine overheat warning light or even an audible buzzer.
You can control the engine temperature both through the on-board computer display and through an application in smartphones or multimedia connected via an OBD scanner.
However, there are situations when it is not possible to control the temperature by hardware:
in case of failure of temperature sensors;
a break in their chain;
if the coolant level has dropped below the point where the sensor is screwed in (on older cars with one sensor in the radiator).
In addition to the temperature gauge, overheating is indicated by:
steam from under the hood;
too hot or, conversely, too cold air from the heater;
white smoke from the exhaust pipe;
power drop;
metallic sounds from engine
atel.
HOW TO DO WHEN OVERHEATING
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Since the consequences of overheating can seriously affect the condition of the engine - lead to the destruction of the cylinder head and the block itself, lead to jamming and costly overhaul, it is strictly forbidden to ignore the symptoms of overheating without finding out its cause.
It should be noted that overheating is most often of an average nature - without the antifreeze boiling away, when the arrow rose only to the beginning of the red zone, it does not bring fatal consequences for the motor. In this case, you can, after letting the engine cool down, continue driving to the place of repair, observing safety precautions.
Stop in a safe place. If no extraneous sounds are heard from the engine, do not turn it off immediately, let it run for a minute or two at idle.
In the warm season, open the hood immediately, in the cold - wait a few minutes so as not to cause cracks by the temperature difference.
Inspect the engine, pipes, the area under the car and the passenger compartment for coolant leaks.
Do not open the radiator or expansion tank immediately - this is fraught with steam burns or at least - the loss of an impressive amount of coolant. Wait for the engine to cool down (hands can tolerate the temperature of the nozzles).
Remember, antifreeze, especially based on ethylene glycol, is a strong poison. If it enters the body, even in the form of vapors, it causes poisoning.
Check the fluid level in both the reservoir and the radiator.
Do not add plain tap water to the system, especially from puddles or reservoirs. If there is no suitable antifreeze, it is better to fill in distilled water, or another class of antifreeze, but then it will need to be replaced as soon as possible.
If it was possible to restore the coolant level, no leaks or obvious malfunctions were found, move at an average speed, avoiding high speeds, bypassing traffic jams and constantly monitoring the temperature. Otherwise, do not attempt to start the engine, have the vehicle towed to a place of repair.