Purging the water ?

1. In wrong section
2. Make and model would help.
2.5 Have a water can of hottish water and one to top up initially of cold water.

3. Is the way I used to purge air out of mine old cars.
Filled to level allowing it to drop lower if it does top it up. Start engine with FILLER CAP OFF. it will bubble pushing air out, and the level will go down just top it up. As you run the engine longer use the warm water to top up if the level drops. [never put cold water in hot engine.] Now check level if stable at correct mark replace the cap and keep engine going for a bit see whether it drops further. If it does turn off engine wait for it to cooll or you'll get scolded. Then remove cap placing a thick towel over the cap to protect from hot steam. Top up with HOT water if necessary.
That's how I purged air out of my engines.

Bob
June 2009