Ok, so I realise it's a 9 year old truck with 90,000 miles on it, but it's also been well maintained. Even the coolant was changed last year, well before the interval.
Tonight when I got home from driving to and from Branson to SPFD, 1 hour each way, and towing my boat a total of 6 miles, and running the ac, the truck was literally on it's last leg. It's like it had run a marathon after smoking a pack of cigs. I opened the hood, and although there was no steam, every surface under the hood was hot. Obvoulsly hot engine = less power.
You would think with the heat extractor hood, fairly new coolant, and running at highway speeds that the truck wouldn't be running so hot.
Should I add a 180 degree thermostat to the truck, would that be of any benefit?
Could the coolant have "failed" should I have that checked?
Can I trust the factory temp gauge? It didn't read over straight up.
( There's no way this could be connected to recently installed 4.10 gears? My RPm's aren't that much higher...)