why does my 2008 jeep grand Cherokee 4.7 keep overheating

Use the coolant bleed port to get the air out, youtube has video's to show this process and bleeding air out if no bleed port too. Does it have an electric fan or fans? If so be sure they operate. May need sensor or fix loose connections or replace. Are any radiator hose's mushy? These may collapse and not allow coolant to pass, replace. Are you loosing coolant and having to top it off a lot? Is your coolant reservoir bubbling or boiling?

Thanks this has helped tremendously!!! Changed out the thermostat because was getting the transmission over heating in my 2009 Jeep Grand Cherokee. Changed the thermostat and refilled coolant still over heated.... frustrated and did not reading finally undid the bleeder screw in the radiator and it took another container of coolant. Heat started working and the air that was released was very noticeable!!! Fixed the whole issues and saved me over 250 bucks the dealer was going to charge me just to diagnose the problem. Awesome post on this thread thanks a ton!!!!