one other inexpensive troubleshooting tip. at napa and i am sure at other parts houses they have something called a cylinder block tester kit.its a syphon bulb that uses a blue liquid that turns yellow when carbon monoxide gases are present in your cooling system. check this out http://www.troubleshooters.com/tlitthypothesis.htm

96 SPORTAGE 4 DOOR:1 3/8 body lift:eibach springs & spacers:15x8 rockcrawlers & 31x11.50 super swampers:warn hubs:winch bumper http://www.cardomain.com/ride/2115301