After a DIY drain and fill, I can't seem to get all the excess air evacuated. I've pressurized the system , let it warm, then vented via the screw in the upper hose. (prolly twenty or more times) & I've checked the expansion tank to add coolant as needed after venting. Every time the vent screw is opened I get the sound of air escaping, and no coolant flow (which is what I read to expect).
I've hit a wall on this one, help please.
-chris