Idling in Dallas traffic this afternoon (ambient 106; heat index was probably around 115 on the freeway), my 2017 started overheating. Yes, the coolant is full and the radiator and charge air fans were working hard (could hear them loudly from the cabin). I checked the radiator when I got home (after it cooled down), and the fins don't appear to be dirty.
Coolant temp got all the way up to 256 (yikes), but I was stuck in traffic so just kept crawling until I could get it to a side street to get up some speed -- once I got the speed up it cooled down, but every time I stopped at a light it crept back up.
Truck only has 42k miles and the 5 year powertrain warranty just expired two months ago.
Perhaps it's the thermostat. I don't think any of the existing CSPs that I haven't had done (PCM Reprogram for Engine Shudder, and the other one for Cam Phaser Rattle) would relate to this issue.
I'm wondering if there's any damage from it getting that hot.