The engine gets very hot
Draw the line where you just have to two options: a valid motor overheating due to mechanical failure or breakdown of the temperature sensor. The latter, as you might guess, is the fault of instrument alarms, and although the immediate threat to the machine, in this case there is, the driver gets nervous.
False alarm overheating engine
Take the simplest option. The car is behaving normally, the readings, which you occasionally looked too normal. And suddenly, once again looking at the temperature gauge, you can see that his hand reached the limit of the scale, even though the machine's behavior has not changed, and the pair is not pulled out from under the hood of the car. This is a typical sign of failure of the device. Stop and open the hood. It is likely that the wire coming to yaky located on the engine block temperature sensor, loose and hung so that its tip concerns some metal parts, that is, the "masses", attach it to the motor temperature sensor.
Perhaps something else: a wire laid carelessly somewhere rubbing against metal parts and Daughtery to the fact that short-circuited to the "masses." Not excluding, of course, and damage to the device itself, but it happens very rarely.
Check how the sensor is out of order, you can; two motor temperature sensors, one stands on the engine, and the other in the instrument unit, pull off to the engine temperature sensor wire and take a look at the sensor in the instrument section of the cabin, if the sensor does not change, then spoiled the sensor unit of the device.
If you pull off holds a temperature sensor on the engine arrow on the instrument readings changed, or vice versa, or any high level has fallen to zero (it depends on the particular connection type ratiometric or pulse) means the sensor unit of the device is OK, change the sensor which is on the engine.
Spoiled sensor unit of the device when removing the wire from a temperature sensor on the engine without changing their shows, then touch the leadership directly on the engine (ground) if the sensor is again not changed their shows, so spoiled by the sensor block devices or wire break or a short to ground it is checked to be sure the ignition switched on (engine start does not necessarily). If you turned off the ignition and remove a wire from the sensor temperature sensor on the engine block devices reset their testimony to zero, look in the wire to ground.
Now everything is clear that lies some of the sensors, it is possible to go further but at the earliest opportunity, of course, be sure to adjust the sensor is deformed.
The causes of engine overheating
In the hot season, when driving on the road is very heavy in low gears or "jerking" in urban traffic a zapolzaniya arrow thermometer into the red zone of the scale, may not indicate a malfunction. In such circumstances, if there is no second exit, and the readings continue to grow, you have to just stop and turn off the ignition, the engine to cool down.
During the forced stop is useful to make sure that the coolant level in the radiator is normal but if you pulled out the steam from the radiator is not any way without opening the radiator, firstly you can greatly scalding, secondly much coolant will pour out on the ground, just wait a few minutes until the engine has cooled itself and then Check the amount of liquid in the radiator. If the fluid in the radiator is small, it is the cause of overheating, the fate of the liquid.
If the engine is in full swing, be sure to shut off the right, and then there are instructions that let the engine running at idle and it cools down, it is 10% and 90% of the engine will boil more. For example, you drive a mechanical fan drive (belt) is idling in a very small torque and airflow of the radiator is not great. Also, there may be mechanical failures in the cooling system and the coolant stops circulating.
Engine overheating due to faulty thermostat