Truck: 2019 (old body style), 5.3L, 4x4, 17,000 miles, towing and driving elevation:4000’-8500’ Trailer with Jeep: 5600lbs Recently bought a tandem axle flat trailer and a wrangler to off-road. While towing a few months ago, I would notice the coolant temp would go from just under 210 to the green arrow line under moderate to heavy acceleration. The temp would stop there and then reduce a bit and hold between the green arrow line and 210. Once I crest the hill or let up on the acceleration, temp would be back to normal. I chalked it up to towing and truck being under load and didn’t dig into it deeper. Now that’s its summer I’ve noticed the same thing happen when I’m not towing or hauling anything but am at freeway speeds under heavy acceleration or steep inclines. The coolant temp will do the same as the above. Coolant is full. Trans temp stays between 190-200 while towing and around 190 while not towing. Only thing I can think of is if the grill dampeners don’t open till I hit the green line and then once they do open and let a lot of air to the radiator, the temps reduces a bit and then all the way once the load on the truck is reduced. Then the grill dampeners close again and the cycle starts again on the next hill. I’ve tried serval times to get the temp gauge to go higher than the green line when the outside air was 85 degrees and I really laid into the accelerator while towing but temp wouldn’t get past the green line (steep incline for 1-2miles, 3500rmps-4000rmps, 5600lb trailer, AC on) Is this normal? Sent from my iPhone using Tapatalk