The first reason - the cooling system antifreeze insufficient.This means that somewhere microcracks were formed, which implies a liquid.If you are already faced with the repair of cars, it is easy to find the leak.After a long downtime of the flowing pipe or radiator may indicate a wet spot under the car.If you are unable to detect the leak from the outside, then you should immediately contact the service center, as there is a strong likelihood that the cooling liquid enters the engine itself, in oil or in cylinders.This can lead, and hammer and other irreversible consequences.
second reason - the problem is the fan.If your car is "forced" the fan, be sure to check the belt tension.Its attenuation giv
es poor cooling effect.If the fan should the temperature sensor, then it can be assumed that the failure in the sensor itself.Look, if the radiator clean, motorists often forget to wash it, and yet the dirt poor conductor of heat and cooling units of the engine plays a negative role.If you washed the radiator and the engine is still boiling, then simply replace the old radiator.

third reason - the failure of the thermostat.Over time, the internal components cease to be elastic, and as a result the thermostat "banishes" antifreeze in a small circle (which leads to overheating of the motor), or large (resulting in problematic heating of the car in the winter).Corks, constant braking at traffic lights can also lead to overheating of the engine due to insufficient obduvaemosti.
Reason Four - engine can boil if the exhaust valve burst.In this case, the motor get hot gases and heated up to the temperature limit.To determine the bursting of the exhaust valve may be on the direction of the sensor, which rise up to the red mark.