Water leakage

Engine Cooling problem 300000 miles

Pls help me,
Water leaking from the radiator. I could not see any out side leakage. I have cleaned the radiator and checked for any damage. It is Ok. I week before, water was mixing with oil. There was a crack in the Egine head. So the mechanic changed the head and gasket. But still water is reducing from the radiator. I checked the connection hose. There is no water drops out side. So what can be teh problem? What parts I need to replace
Pls help me.
Viju