99 suburban overheatimg
hey guys im new here been reading a lot of advice as a guest here is my problem my 99 needed new head gasket so i replaced and did also replace heater core,water pump,radiator,t stat fan clutch,now when it runs it will go up to over heat,so i checked t stat and noticed no coolant in upper hose so i ran with out t stat and coolant flows to radiator i tested t stat and it opens,put it back in same thing any ideas thanks in advance
Sounds like air in the system.
Try parking on a steep hill with the nose in the air, remove the cap and water may push the air to the highest point (the top of the radiator). If gravity doesn't do it, you may need to run the engine so the pump can help.