I have a 00 Disco II that is running hot. Out the blue it started running hotter than normal while idleing after bout a 20 mile ride. Saw it got close to the red and turned it off. Let it cool down and checked the coolant and it was some in there started bubbling out after I lightly loosened the top, and yes i know what would have happened if i tried to open it while hot. Started getting hot again maybe 3-5 min after starting to drive again but i was pullin into my driveway. There was no heat at all while sitting idle and started to run hot after letting it idle for about 10 min and revving the rpm up to bout 2400 a few times. Turned off, loosen the Rad Cap and the Release valve on the hose and let the pressure out. Tighten the release valve and left Rad Cap off while i turned the car on and let it run for about 3 min before putting Rad Cap back on. After that it ran in the middle of Hot and Cold, no problems. Until I stopped for a while and started back driving again. Water pump is 2 months old, just changed Thermostat 2 days ago. Still acting up. Is it possible that I have air in the system, or the radiator or one of the hoses is clogged? Need Help.....Anyone????

 

Fill and bleed your system, then go get the coolant system pressure tested with no driving around until it is checked or you'll be looking for a new engine.