So I think I have a small leak at the heater core. I can smell a very odd smell almost like sweet/electrical/antifreeze (ish). It is most prominent when I turn the heater on and the engine is cool. There are no obvious puddles on the carport floor and the floorboard is not wet. The smell mentioned above can also be smelled in the engine compartment and is most noticeable on the drivers side. It makes no sense to me. The heat still works, there is no fogging of the windows, and no spray on the windshield. If i do have a slow leak, is it safe to drive as long as I monitor my temp? What could this be and is there a way to tell for sure whether it's the core or not?