A little supplemental info on my ordeal here. I'm an automotive repair tech, with a specific GM background. I know the MFG's build these things so that anyone can get in and drive one with no mechanical experience needed. That means anyone should be able to load up a the vehicle to its max GCWR, put it in drive and go thru Death Valley in 125 degree heat with the A/C on and climb the steepest grade and not run hot or overheat. Mfg's spend millions of dollars in R&D and testing to make sure the vehicle operates this way when they make and sell them. So assuming my gauge is accurate and I really am getting up to that temp on long hard grades, something isn't working at 100% efficiency and I need to figure out what that is. I've also verified that the engine ISN'T using any coolant. Just after I took that pic, I stopped at the top of the grade and measured the temp at the upper radiator hose when my dash gauge and scan gauge read 225 degrees. With my IR gun pointed at the upper hose (at the radiator connection) was reading 215 degrees. Just a little bit of misc info to digest. If I can't get the selling dealer to help me solve this problem, I will pull the radiator and have it checked to see if its plugged. after that I will add a severe duty fan clutch and see about testing and/or installing a manual temp gauge to see the real engine temp. Wish me luck.
