What is the reason why the cooling fan of BMW 525 turns to the sewer pipe at high speed?

The speed of the cooling fan of the automobile is very high, but the reason why the water pipe temperature is not high is generally caused by the air in the cooling system. We need to vent the air from the cooling system. It is recommended to check whether the coolant level is normal, whether the water circulation is normal and whether the thermostat can be turned on normally.

We must exhaust the air in the cooling system with professional tools. First, we must vacuum the cooling system. In the absence of air, we can use the suction of vacuum to suck antifreeze into the water tank and cooling system. After this, we will get on the bus, blow warm air at the highest temperature, then blow cold air at the lowest speed, and step on the accelerator for more than 15 seconds. After the engine is started, it starts running around 1200 rpm, 65438.