Coolant bleeding
E36 325i M50B25 1995
I replaced my water pump and thermostat and proceeded to bleed by following the guide I found here :
>!1. Open the cap for the expansion tank and also unscrew the bleed screw until you can see the red seal.!<
>!2. Turn on your ignition, set fan to 1 and heat to max.!<
>!3. Proceed to fill the expansion tank (engine off!) with the bleed screw opened until the level reaches the top of the expansion tank. Keep filling until the system stops sucking down the water. Close the bleed screw.!<
>!4. Proceed to open and close the bleed screw, while filling in coolant, until no more bubbles come out of the bleed screw.!<
>!5. Close everything up, then start the engine and run for no more than 30 Seconds.!<
>!6. Reopen the cap and bleed screw and do one more fill with the screw open.!<
>!7. Using a syringe, remove the amount of coolant you need to reach the “cold” level.!<
>!8. During the test drive, keep the fan on 1 and heat on max. If you’ve done it right, the heat coming out of your vents should be borderline uncomfortable.!<
>!9. Allow the engine to cool off (ideally over night), then do one more bleed.!<
After the last step, I filled the tank fully and proceeded to open the screw. Once no more bubles were leaving I removed some coolant until I reached the KOLD mark.
Then I went for a 30 mins drive, everything was fine, engine was at normal operating temperature, hot hair blowing, both upper and lower hooses where hot. There are no leaks.
But one thing seemed off : my coolant tank was empty. I’m not sure but the tank shouldn’t be empty when the engine is at running temperature. Whats the problem and how to fix it ? I’m still waiting for the car to cool down right now but I believe once it cool down the level will be at KOLD mark again. What did I miss ?