1, its function is to raise the temperature of the engine and make it reach the normal working temperature of the engine. Working at this temperature, the engine wears the least and saves the most fuel.
It is very cold in winter in the north. Without it, warm air would not be hot. If your car is old and diesel, it has no obvious effect on fuel economy, and it is hot in the south, so it doesn't have much effect to remove it.
3. Generally, the thermostats of family cars are in the engine factory, next to the water tank, and the design places of different car factories are different.