The Jetta's thermostat is located in the joint between the water pipe and the engine under the generator. Unlike most models, the Jetta's thermostat is installed in the return pipe joint.
The thermostat can change the circulation range of water to adjust the heat dissipation capacity of the cooling system and ensure that the engine operates within a suitable temperature range. The thermostat must be kept in good technical condition, otherwise it will seriously affect the normal operation of the engine. Extended information
1. Thermostat failure phenomenon:
1. In the first case, the thermostat is always open, which will cause the engine coolant temperature to rise slowly and fuel consumption to be relatively high. Especially in winter, the warm air will not be hot, and it will take a long time for the warm air to return.
2. In the second case, the thermostat is in the normally closed state, which will cause it to be in a small cycle all the time, and the engine temperature will rise rapidly, resulting in high engine temperature, water pipe suffocation, and serious damage to the engine.
2. The working principle of the thermostat:
The main thermostat used is a wax thermostat. When the cooling temperature is lower than the specified value, the thermostat senses the temperature. The delicate paraffin in the body is in a solid state. The thermostat valve closes the channel between the engine and the radiator under the action of the spring. The coolant returns to the engine through the water pump to perform small circulation within the engine. When the coolant temperature reaches the specified value, the paraffin begins to melt and gradually turns into a liquid. The volume increases and presses the rubber tube to cause it to shrink. When the rubber tube shrinks, it exerts an upward thrust on the push rod, and the push rod exerts a downward reverse thrust on the valve to open the valve. At this time, the coolant passes through the radiator and thermostat valve, and then flows back to the engine through the water pump for a large circulation.
Baidu Encyclopedia - Thermostat
Baidu Encyclopedia - Jetta