98 ford explorer sohc 4.0 getting hot and leaking coolant?

i changed the water pump, thermostat, flushed the radi. , put on a new radi. cap, and put on a new fan cluch and my truck still gets hot. it is leaking around the thermo. houseing when it gets hot and you can hear it sizzling around the two sensors. could the sensors be causing the over heating. please help me.