Generally speaking, the cooling system can be divided into two situations: with water pipes and without water pipes:
1, automatic exhaust return pipe.
As long as the return pipe does not block the smooth flow of water, there is no need to manually exhaust; There are two water pipes on the kettle of this car, one is to feed the engine, and the other is to the return pipe at the water tank or cylinder head. It should be noted that after adding enough water, don't screw on the lid immediately, start the engine, and then screw it on after the running water in return pipe continues. If the lid is tightened in advance, the air in return pipe will not be discharged, and the water in the system will not circulate, which is prone to high temperature.
2. Don't bring back the water pipe.
There is only one water pipe on the kettle, so this car must be manually vented, otherwise how much antifreeze can be transferred out; What I want to say here is that the exhaust position must be selected correctly, otherwise the air exhaust will not be complete.
3. Exhaust method of BMW car equipped with electronic water pump
A, after filling antifreeze, open the water tank cover, then insert the key and turn on the ignition switch (don't start the engine, but turn on the power supply).
B, air conditioning warm air mode, maximum temperature modulation, minimum air volume modulation.
C, driving lights, namely the headlight switch to the right.
D, step on the accelerator to the end, about 10 seconds, you will hear the sound of the electronic water pump working.
I hope it will help you, and I hope it will be adopted. Thank you!