BMW E38 cooling system bleeding
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How do you bleed the E38 cooling system?
1. Bleed with a cold engine, engine switched off. 2. Switch the ignition on so the electric water pump runs. 3. Open the bleed screw next to the expansion tank. 4. Add coolant until no more bubbles come out of the bleed screw. 5. Close the screw and the cap.
How can you speed up bleeding the cooling system?
First fill the system as full as possible through the upper radiator hose, then bleed through the expansion tank. Raising the nose slightly and squeezing the hoses helps. If the expansion tank runs empty, the system sucks in air and bleeding has to start over.
Can you bleed the cooling system on a hot engine?
Not advisable. Hot coolant boils when the pressure drops as the cap opens, and it can spray out. A small air bubble can stay in the system, so check the coolant level cold for a few days before every drive.
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