i have read many times alto users facing leaking heater core. the whole dashboard has be removed for its replacement. AC technician will do that....
Zic, total are best coolant though expensive ensure no leakage before using..........
drain plug in alto is at bottom see carefully a white plastic type screw.
for flushing drain the water, remove thermostat. install back the hose pipe, put water, drain again, put radiator flush with water, drive around for 15 mins, drain the water,put fresh water circulate it and drain it until no foam is present, check for leakages, then install thermostat, and put coolant 50: 50 ratio with water...regards