Hey all, just wanted to pass along some info I found on YouTube. I have a 2018 F150 3.5 and I had ford flush the coolant at 30K miles. Ever since the flush the truck has been running hot. Any time I was in boost the temp would spike around 236*. For was at a loss and was unable to replicate it, mostly because I needed a big hill to sustain boost for 15 seconds or more.

apparently this is a common problem after the cam phaser replacement because they drop the coolant during the repair.

The fix is a new thermostat. The talk is the old thermostat has a metal shaft and is causing issues with the new coolant. The new thermostat has a plastic shaft. Here is the video. It’s not mine, but this was the fix for me. Good luck!

https://youtu.be/Fz2ZduzMnXg