Temp guage started up with the air conditioning on going up the grade from the 5/14 split northbound. It didn't get anywhere near the redline but was moving up and the minute I shut down the air it went down a little. The rest I did for protection of the engine and nothing more. Guage moved just a little upward coming home as I struggled up the southbound grade. I'm a little paranoid (no, not as bad as E9999) as I cracked the upper housing of the radiator w/o the trailer two years ago along the grapevine (12 year old radiator). I'm very careful now wanting to keep the engine as cool as possible. Turning on the heat helps disapate the heat a little. Besides, with the windows down this past weekend, I think the hot air coming from the vents was cooler than the outside temp!
Engineers are more anal and paranoid than bean counters! 