Replacing the coolant (BMW 5 Series E12)

Remove the hex head cap from the lower radiator tank.

Remove the hex plug from the engine block.

Remove the radiator filler cap.

Note: When draining the coolant, the heater valve control switch handle on the instrument panel should be in the "Warm" position.

Install the heater control switch (left handle) to the "Warm" position.

Fill the radiator expansion tank with fluid.

BMW "525", "528"

Loosen the air bleed nipple (headless screw), located on the thermostat housing and fill the system with liquid through the expansion tank.

After the liquid with air bubbles stops coming out through the air bleed nipple, tighten the nipple.

Fill the expansion tank to the mark. Install the radiator cap.

BMW "518", "520", "520i"

Fill the radiator slowly through the filler neck.

Replace the radiator cap.

Start the engine and warm it up at a crankshaft speed of 2000-2500 rpm.

Stop the engine.

After about 1 minute, start the engine again.

Let it run for 30 seconds at a speed of at least 4000 rpm.

Make sure that when the engine is idling, a stream of warm air comes out of the heater.

Cool the engine (until the pointer arrow is positioned between the two white marks).

Add liquid to the radiator to a level of at least 2 cm below the plug. Excess liquid will be immediately removed through the bypass plug.