92 Explorer Coolant leaking from engine

I have a 92 Ford Explorer. I recently thought I had a leak from the water pump. I changed the pump to find that the leak was not the pump but coming from something else. The hoses seem fine but it is still leaking somewhere. I can see the coolant drip down but can't pinpoint where it is coming from. It also makes a hissing sound when hot. Could this be the engine. Thanks in advance for your reply.