Over heating Cadillac

Is it leaking from the water pump? Where the 6-8 little 10mm bolts are, at the hub end of the pump, they thread into an inlet that is behind the timing(silver) cover. Is it leaking at the front portion of the pump? If so, I would suspect that the problem may be behind the timing cover at that inlet. It is kind of a sandwiched design, where the pump and gasket seal to the timing cover, and the inlet and it's gasket seal to the rear of the cover, using the bolts from the water pump side. The overheating is either due to low coolant, or there is air trapped in the cooling system. If there is no heat from the heater, it could indicate either of these conditions. Air can trap in this engine as the thermostat is situated higher in the cooling system that the radiator fill.