Everytime i put coolant in my radiator its gone in a day?

I just changed my thermostat like to days ago and it stopped the overheating for like 2hrs when i came back home i noticed the new coolant i put in the radiator and reservoir tank was completely empty my radiator is new as well as my head gasket and waterpump the reservoir tank is new 2 i don't know what else it could be the only thing i know what's wrong with the car is that the exhaust manifold is cracked and it needs a tune up its a 1998 honda civic ex 1.6 4 cylinder can someone tell me what might be wrong with it should i just get a new engine i put so much money into it i don't want to sell it cuz i love that car lol it was my first lol

When you overheat an engine to the point where the head gasket blows, you sometimes get cracks in the head and/or block, which let coolant out.

Also, have you checked hoses, freeze plugs, heater core, radiator cap?

You got a leak… Watch your exhaust… If its internal then it could be intake manifold.