Ok, so this is a tangent, still a road trip, but not local: The wife and I drove up to Vegas two weeks ago for a 4 day trip. We left on July 10th about 2 in the afternoon. No traffic on the way up, except for a little bit of nonsense on the pass going up to Victorville on the 15. As we got north of Barstow we just kept seeing the outside temperature slowly (not that slowly) climbing from 105 to a blistering 122. That readout was on my sat nav display. Most likely it was a couple degrees high-ish. So I have the AC dial on "2" and set at 74. The car has been reading 4 bars on the engine temperature the entire trip. That is where the car reads it's temp about 2 minutes after I start it up in the morning and stays there all day every day. I have never, in the 37k miles and 7 years owning the car, ever seen 5 bars or higher....you can already tell where this is going. Temp displayed on the "world's largest thermometer" at Baker reads 119. Just north of Baker is a long stretch of an uphill climb for miles. My wife sees a sign and reads it out loud, "Uphill gradient for the next 16 miles, please turn off AC to prevent overheating." She didn't even get the C out in AC before I shouted, "FUCK THAT!" The person who put that sign up did it in February and has never gone outside in the desert since. We're cruising, listening to old school Vegas tunes (i.e. Sinatra, Darin, Martin, etc.) when my wife hears a bong. I didn't hear it. 10 seconds later..."bong". Turned off the radio..."bong". On that bong, I started to loose horsepower. Looked at my dash readouts. Temp light is on and the temp gauge is pinned at a full 8 bars! We still had about 10 miles of uphill to go. I got into the truck lane, slowed to 60 (I was doing 80) and turned the AC off. Within 30 seconds we were drenched in sweat. We killed off the rest of the water we had by the time we got to the top of said hill climb. Temp slowly came down to 5 bars by the time we got to the top. Once it leveled out, I turned on the AC to "2" again and set the temp at 78. Car balanced back out at 4 bars, so I picked up the pace to about 72 mph. I was fine the rest of the way to Vegas and all the way back home.
Although, going back home I usually get 3 mpg better than on the way up. I got 35.1 to Vegas, but only managed 29.3 coming back. Very strange.