I have been having difficulty with my cooling system for a while now. My radiator, thermostat and water pump are new (as of 1 year ago). Recently some ******* took the radiator cap off unbeknownst to me. About 5 minutes into my commute the radiator boils over and I am stuck walking to a local auto parts store to get a radiator cap and put coolant/water in the radiator. Ever since then I have been having an issue at idle. The jeep tends to get warmer at idle, if I gas it the temp gauge goes back down. I have checked the top hose and it's warm telling me the thermostat works. I get hot air from the heater to my water pump works and the radiator is new. The fan is always on.