my coolant keeps getting low to the bottom and the gage is going up on high

I AGREE WITH HAVING PRESSURE TEST DONE FIRST BUT IF U ARE NOT SEEING COOLANT ON THE GROUND I WOULD START LOOKING AT THE HEAD GASKET ASSOCIATED WITH THE "ENGINE OVERHAUL".

The best way to find the leak is to have the cooling system pressure tested, Coolant loss can come a variety of places, water pump , heater core, cooling hose, radiator and the list get bigger, the best solution is a cooling system pressure test