A quick heater core swap is in order here.. Before swapping do several coolant flushes. Get that damn barrsleak out of the system. Stopping up the heater core with it should tell you what it has done to the radiator itself.
The coolant smell was just what you thought it was... a leak in the heater core. Then the barrsleak stopped up the leaky area and prolly much more.
Big JIm

professional bovine relocation specialist