I have a 1996 Suzuki Esteem the guage light is reading Hot.The radiator was empty of water. I filled it up and the water is gone again after a week.I can't see where its leaking out from.I started the car and let it run for 10 mintues and looked at the radiator know water coming out of anywhere.Hoses look fine.Then It sat for two hours and when I went to go start it the window was full of condensation so I am thinking Thermastat or water pump.How do I change it myself?