the heater core and a/c evap are housed together so if heater core leaks i can see where coolent could run down tube ment for condensation removal. good luck i have changed heater cores on several cars and have only once had a easy time of it. you dont say the year of car but i can tell you the newer ones have special hoses that snap on to both heater core and eng if you have clamp on type get adpt and run hoses together forming loop back to eng for now. at least you will stop leak, that can overheat car. that can give you time to get the heater core replaced. again good luck