Where is the thermostat located in a Jetta?

[Melissa]

The thermostat in a Jetta is installed in the return hose connector. Below is how the thermostat works: 1. The thermostat is a valve that controls the flow path of the coolant. It is an automatic temperature-regulating device, usually containing a temperature-sensing component that opens or closes the flow of air, gas, or liquid through thermal expansion or contraction. 2. At normal temperatures, the wax remains solid. When the water temperature is below 76°C, the main valve is completely closed, and the bypass valve is fully open. Water from the cylinder head flows directly into the water pump through the bypass pipe, which is called a small circulation. Since the water only circulates between the pump and the water jacket without passing through the radiator and has a low flow rate, the cooling intensity is weak.