Hi i have an 06 gto today it instantly went from normal running temp to the last red mark. I noticed that my overflow tank was leaking a lot of water out too refilled the radiator with water since it was low and wen i turned the car off u could hear the upper hose to the water pump suck a mixture of air and water?? should i replace the thermostat? or is there a way to bleed the cooling system? or is the water pump?