I changed the heater core on my 97 F150, I'm trying to get rid of the air in the system. I have placed the truck on ramps and ran it for 30 min (with cap off), not working upper hose still luke warm at best to the touch. I know the t-stat and water pump are good the truck does not overheat and I get plenty of heat in the cab. Am I over-thinking this and everything is ok ?? I,ve never had a upper radiator hose NOT get hot to the touch after 30 min.

Any advise would be great