[Anti_Rice_Guy]

Ok so my dad's truck, pretty much since new has had this issue. If you have the plow on and don't let it get close to operating temp before you start driving, it will start overheating after about 20 min, regardless of terrain or how high the plow is. It will start going just above 210, then the gauge will start booking it towards 260 in a matter of like 20-30 seconds.

Mind you, if you pull off, shut it down, restart quickly and let it idle with the plow down on the ground, it'll cool down to regular temp (just under 210) in about a minute or so, and as long as you don't shut off the truck again, you could drive through a huge hill in the Sahara and the temp gauge wouldn't budge.

Background:
6.0 motor was replaced under warranty and send back to GM at 33k miles due to a random rattle not found and literally like 3psi of oil pressure at idle, and maybe went up to 10-12 under throttle. Truck now has 188k miles. Is equipped with the tow/haul and plow packages.

Thermostat was replaced 2 years ago in an attempt to solve the issue and hasn't change anything. It seems like the thermostat isn't opening right or something.