I have had that happen in another vehicle but it may be the heater core.....how can I tell? If it is the heater core, does the dash need to come out to replace the heater cote?
My passenger side floorboard is getting soaked...is it a stopped up drain plug? on 1993 Nissan Pickup (D21)
see if fluid tastes sweet if yes its coolant. hr job for a good tech. dash needs to come out to a certain point yes