Over heat's/No heat/And no fluid loss

What is your question?

Van keep's over heating and just before it over heat's it loose's it heat.It keep's getting air somewhere.Flushed it,new water pump,2 new Thermostat's,and also replaced lower intake manifold.The only thing not replaced Head's and gasket's.And not once is it leaking fluid in oil or out exaust. Raditator stay's full.