Request for ideas. I have been chasing a slight overtemp issue with my 2017 5.0. Today I got a chance to play with it and it is running warmer than it should and I have now pinpointed what is happening but need some help coming up with a cure. The reason I have never noticed is the gauge always stayed centered and I always ran with the A/C on. It is a habit you acquire in the SE. Now for the scenarios.
A/C on: shutters open completely runs up to about 203 and low fan comes on. If temp continues to climb the high speed will come on.
A/C off: The shutters remain closed and the low fan will come on at around 205-206 and run for a few minutes and then the temp drops to 203. Shutters may open 5% but remain closed most of the time. Hit the A/C and shutters open up.
I have only had one power derate and that was after a quick fill up just East of Nashville. Other than that it just runs on the North side of 200 all the time with an occasional drop to 195-197 when moving. it just troubles me that the shutters stay closed on extended idle at above 200. I may be chasing a ghost but the shutter operation seems a little odd.

Input please.

 

I'm back and I have hard data. I spent the later part of the afternoon checking relay locations and fuses just to make sure I had not removed one and put it back in the wrong slot. All was OK. After supper I decided to take a nice long test drive with A/C off and see what happens. Take off and up until about 10 miles in the engine stayed around 206 and the trans about 200. Got on an open stretch of road and nailed the throttle to build up some engine heat. I pulled over at 213-214 and hopped out. The shutters were open about 10-15% with no fans. Went to glance at trans temp and the fans kicked in. Walked to the front of the truck and the shutters were wide open and my phone was showing 221. Took off and the temp dropped to 210 with the trans staying around 200. Kicked on the A/C and checked. Fans on low, shutters wide open. Turned off the A/C and hit the road again. Stopped about 6 miles later with the engine temp about 212. Hopped out and watched the shutters start to open at 218 and the fans kicked in at 220. Fans cycled off and temp dropped to 210. Ran an A/C cycle on the run home and the engine stayed at 200 and the trans dropped to 195. Turned off the A/C and returned to the house. Let the engine idle and it repeated the 218 - 220 dance. I knew they ran these late models hot but I did not think they ran them that hot. When I retired 12 years ago BMW was running everything in the 202-206 range before fans cycled. I thought that was hot but nothing like today's cars.
I can honestly say that I chased the ghost and caught it this time.

 

I almost always run with the A/C on unless the windows are open and even then I forget to turn off the A/C. I dont have anything to watch actual engine temp but I will turn off the A/C and see how hot the trans gets. 220F trans temp isnt a problem on these trucks. They designed the fluid to take hotter temps and designed the trans to run hotter to try and squeeze more effeciency out of them, better MPG's. That said, I dont think I have ever seen over 196F trans temp with the truck unloaded.

The old school in us cant help but think there is a problem, but there isnt.

Edit; we are however talking 10 speed vs 6 speed here. And your friends 2018 truck has a 10 speed too. So characteristics may vary.