When the car engine warms up too quickly, almost immediately turned on the electric fan, and the arrow sensor coolant temperature inexorably rising towards the red zone, threatening to overheat the engine, there is every reason to talk about abnormal operation of the cooling system. Very often the cause of such a failure is the thermostat.
We blame the drivers and thermostat if the engine slowly warms up to operating temperature and the needle temperature sensor is rooted to the spot at the beginning of the scale.
the Principle of operation of the thermostat
The purpose of the thermostat is to block the access of coolant to the radiator until until its temperature reaches a certain value (from 85 to 950). This task in most thermostats are implemented using the valve leading to the lower pipe of the radiator.
This valve is connected by the pin with the cylinder filled with technical wax, which has a melting point equal to 850 C. While heating the coolant to a specified temperature before the same temperature is heated and the wax. Prehoda from the solid to the liquid state, it expands significantly, pushing out from the cylinder the pin that opens the valve.
As a result, the coolant begins to circulate in a large circle cooling system, giving the most heat through the radiator and being cooled. At least reduce the engine temperature the wax in the cylinder thermostat reduced in volume, closing the valve and starting circulation of the coolant in a small circle of the cooling system.
test the thermostat by car
To check thermostat car engine to run and warm up to regular temperature. After 1-2 minutes after start when the arrow sensor coolant temperature has just started to deviate from the edge of the scale, you should check the heating pipes leading to the radiator. The lower pipe should stay cold, and the upper little warm. Moderately warm should be and the pipe leading to the oven interior.
As the heating of the engine, the upper nozzle of a radiator should become hot, while the bottom stay cold. When the temperature reaches the thermostat operation (it is applied on the casing or stated in the passport), the bottom outlet of the radiator will become warm and then hot. It is a witness to the valve of the thermostat. In warm or hot weather followed by should be included and the electrofan. This arrangement of the thermostat is normally.
If in the process of warming the engine becomes warm, both the pipe of the radiator, this indicates that the thermostatic valve is due to a number of reasons is always in the open position, starting circulation of the coolant by the cooling system.
Another possible variant is that the engine is warmed up, turn on the electric fan and the lower radiator pipe stays cold. In this case, the thermostatic valve remains closed and does not open even when heated coolant starting to circulate on a small circle of the cooling system.
Both last options clearly suggests that the thermostat is defective and must be replaced.
health Check removed the thermostat
Check the operation of thermostat at home is very easy. All you need is a saucepan of boiling water. Lowering the hot water thermostat, wait a few seconds while it warms up. In case his health will be perfectly clear how moved the rod and open the valve of the thermometer.
Exactly the same will happen clearly and closing the valve in case of cooling of the thermostat under running water or in a saucepan of cold water.
If as a result of home testing proves that the valve does not open and/or close, therefore, the thermostat is faulty.
Engine overheating can occur not only due to the malfunction of the thermostat. In some cases, insufficient circulation of cooling liquid can be caused caused by failure of water pump (pump) or "usage" of the cooling system due to improper replacement of the coolant.
Good luck to you! No nail, no wand!