I'll take a shot, I'm old and patient.Originally Posted by Shawn Rollick
You won't lose much coolant bleeding air out of the system, but yeah some will run out onto your engine then to the ground, but not a huge puddle.
Start it up, let it get to about the first BIG mark on the temp gauge. Loosen just the top part of that brass bleeder. Its a hollow plug with holes in the side so once you unscrew it a little, it creates a leak. If an air bubble is present or if the engine is not warm enough yet, little or no coolant will come out. If so, close it and wait a little longer. The bleeder is the highest point on the engine so when its filled thats where the bubble goes. But the thermostat is right below that bleeder and its a valve that stays closed until the engine is near operating temperature. So, as the temp gauge climbs to normal, the bleeder can spit out the air once water is flowing past the thermostat.
The spitting of hot coolant is less violent if you just open the bleeder barely enough to vent. I like to first do this AS the engine warms up, and until just coolant comes out with no spitting. Then I like to let it cool off all the way, restart it and go full operating temperature before re-bleeding once more. You'll get it once you try it. Just check coolant level in the reservoir and resist any temptation to remove radiator cap. The cooling system is under pressure when hot, but will suck coolant from that tank IF it needs it, to correct the level, as it cools off.
Hope that helps, its long but and hopefully not totally confusing. Peace.
