No, not climbing boulders, but just came down the Shafer trail, and did a short drive to Gooseneck Overlook on the White Rim Trail.
Have to post this and head to Fiery Furnace...
Temp gauge never went above 3/4 so far, had only 100 degree day, but that included driving up Shafer trail with the air on, then sitting at the rim top for about twenty minutes.
Cylinder head still in one piece.