When I start my 98 exporer sport I get a coolant leak into the engine compartment only when the heat is on. when the guage comes up to temperature the leak stops. Any ideas where to look?

When I start my 98 exporer sport I get a coolant leak into the engine compartment only when the heat is on. when the guage comes up to temperature the leak stops. Any ideas where to look?

From what it sounds like the leak would be around the thermostat housing or the hose going to it. I would replace the thermostat and the gasket and that should take care of it.