overflow puke prob

i have a 1987 302 in my galaxie and it seem to not want to keep coolant in it, it pukes out about half the radiators coolant into the over flow tank and does not suck it back in, it has a new pump t-stat and cap? any ideas?

 

Hey Dr post this on the main board you will get a bit more response This is usually the spot for asking about problems on posting.

 

thanks!