coolant leak

td4 problem help please.just found engine coolant leak around water pump,lost most of the water in header tank any ideas please.that was yesterday.today.topped up header tank went for a drive temp on dash got up to normal half way,looked round water pump no leaks but bottom rad. hose not getting hot.maybe pressure is building to much.dont know

Heater rail to thermostat housing O-ring failure is a common one. Cracking around the top of the header tank is also common. Check those first