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 fill it with coolant as recommended by BMW.
To ensure complete removal of air from the cooling system, the following sequence must be strictly followed:
- open the cap (fig. 4.105) on the expansion tank of the radiator of the cooling system;
- unscrew the air bleed screw;
- turn on the ignition;
- set the heater control to maximum temperature;
- set the fan controller to minimum speed (low air supply). This will open the heater block valves and the additional pump will start working;
- slowly pour in the coolant;
- screw in the air bleed screw when clean water starts to flow (without air bubbles) coolant;
- fill the expansion tank with coolant up to the maximum mark. Mark (dash-dotted line) is then at the same level as the upper edge of the expansion tank;
- install the expansion tank cap;
- start the engine and let it idle until the thermostat opens;
- turn off the engine, let it cool down, slowly open the expansion tank cap to relieve pressure in the cooling system, the liquid temperature should not exceed 20°C;
- top up the coolant to the nominal mark in a cold state, when the upper head is level with the edge of the expansion tank plug;
- install the expansion tank cap.
(The original is located on the internet portal: «BMWMAN.RU»)