I think hes dealing with some coolant issues. If you run your climate control on auto its a good posibility that your aux/heater water pump will circulate enough water and keep the X at a normal operating temp. I drove like this for about 400 miles( easy miles ) if i turned off climate control i could watch temp guage climb. Run the heat up and it would go back to dead center on the gauge. Took water pump out and see that impeller has stripped off he shaft.

__________________
______________________

2003 3.0 108,000 (2/10/12)