Attention! The mark on the expansion tank shows the liquid level at a temperature of about 20°C.
Bleeding the cooling system must be carried out in the following order. Check the cooling system for leaks and top up with coolant recommended by BMW.
To ensure complete removal of air from the cooling system, the following sequence must be strictly followed:
- open the cap (pic. 4.105) on the expansion tank of the cooling system radiator;
- unscrew the screw to remove air;
- turn on the ignition;
- set the heater controller to the maximum temperature;
- set the fan control to minimum speed (low air supply). At the same time, the valves of the heater block will open and the additional pump will start to work;
- slowly fill the coolant;
- screw in the bleed screw when clean (without air bubbles) coolant;
- Pour coolant into the expansion tank up to the maximum mark. mark (dot-dash line) is then flush with the top edge of the expansion tank;
- install the cover of the expansion tank;
- start the engine and let it idle until the thermostat opens;
- turn off the engine, let it cool down, slowly open the cap of the expansion tank to relieve pressure in the cooling system, while the fluid temperature should not exceed 20°C;
- add coolant to the nominal mark in a cold state, when the upper head is at the same level with the edge of the expansion tank plug;
- Install the expansion tank cap.