When I got my car back it had a heating issue which was found to be related to the fan becoming unplugged but before that it overheated twice causing antifreeze to gush out of the cap. The first time I filled it up with antifreeze, the second time with 2 containers of water because that was all I had. After resolving the overheating issues I noticed that after a couple of hours the coolant level would be low but only once I noticed that some coolant had leaked from the heater core out the drain line on the passenger side fire wall but only once. Now I check under the car all the time and see nothing but the coolant still gets low. What do you think could be happening? I'm starting to think I may need a new heater core or something because I can smell coolant in the car but I just thought it was leftover coolant from when it overheated the second time and shot all over the engine burning off. Any ideas?