Coolant leak 1992 Explorer

Hi, I have a 1992 Ford Explorer 4dr 4x4 Eddie B. With about 240,000 miles on it. Recently, its been leaking coolant at an alarming rate. There's a constant stream flowing from what looks like the engine heads on the right side behind the thermostat housing. As far as I know the car has never overheated. I have already replaced the thermostat, water pump, and have checked every hose in the area. My question is, is it at all possible that this is simply a popped freeze plug, or are my heads cracked? Thanks for the help.