Frist thing to do is put the thermastat back in. Drill a 1/16 hole in the flange of the thermastat and this will allow the air to get past the thermastat. The STAT will help to regulate the flow of your cooling system.
When you fill the Radiator. When do you stop filling? Where is the coolant level when you stop filling it?
Next when you run/ drive your truck what temp is the gauge reading?
Are you using straight water or a mix of water and antifreeze?
