won't hold full water/antifreeze
 

Hi, I have an 88 ford club wagon, 300 cid, six banger. It likes to puke out water when I shut it off. It will go down just so far, then stop. The problem is that when the water is down, my heater does not work, it just blows neutral temp air. I changed the radiator cap, but no help. Any help on this? Thanks

My '87 F-150 does this to and it is one of my freeze plugs leaking and it doesn't leak when it is under pressure but pours it when not under pressure and only leaks out about 1/4 or 1/2 gallon.