My mitsubishi Montero started over heating yesturday. I changed thethermostat and the pressure valve and new symptoms emerged. When i am driving the temperature is fine, but as soon as i stop the car the temperture sky rockets all the way behind "H" as soon as i start the car again the temperture goes back to normal as long as is in drive. Any ideas to what this might be would be highly appreciated as of right now i am clueless about what it might be.