coolant consumption on 1993 Honda Civic

when car is parked no coolant in radiator but all of its in the overflow any ideas

Asked by for the 1993 Honda Civic
Failed t-stat , radiator fan , or headgasket. Needs proper diagnosis , first-hand.
yeah t stat working but i have no fan i have yet to wire it up i have a feeling it is the head gasket its got over 240k on it i did a whole rebuild but never did anything with the cooling system thank you for you respondz