How to exhaust the air when replacing the thermostat in BMW 525

The exhaust method for replacing the thermostat is as follows:

1. After filling antifreeze for the first time, hold the upper and lower water pipes by hand before closing the water tank cover, and bubbles will appear at the water tank mouth;

2. After several times, cover the water tank cover tightly, start the car and increase the engine speed;

3. When the cooling fan runs at high speed, turn off the fire and add antifreeze;

4. It is recommended to circulate several times until the water level no longer drops and remains at the specified level.