After I finished the install of lower intake and thermostat. My thermostat was leaking my friend installed it housing/gasket/thermostat/silicone/intake. Now Im going to do this again and please correct me if im wrong housing/thermostat/gasket(self adhesive from napa)/intake. Or should I put a little sealent between the gasket and intake? How long should I wait before I start it up to see if it leaks and to flush the radiator? Thanks