Tried to search the forums but couldn't really find anything relevant. Need some help troubleshooting why the truck is overheating. My cousin has a 2016 f150 with the 5.0 platinum edition. The temp stays in the normal range around town and idling and everything. However if you cruise around 60 mph for a few minutes the temp slowly starts climbing. After a few mins it'll pop up above the normal gauge and show 230 degrees and slowly keep climbing. If you let off the gas it'll start going back down and then if you just floor it it'll end up going back down too. We have changed the thermostat, water pump, resevoir cap, coolant temp sensor, flushed the radiator, and bled the system. In stop and go city driving and idling and all it never gets hot enough to display the temp. Both fans are working as well. Any ideas?

 

Hello Curtis

Did you solve this problem? I have the exact same issue...

 

Yea turned out the thermostat was an Autozone thermostat and that was our problem. It would open and close but it doesn’t open as much as the oem ford thermostat opens so it wasn’t letting enough water through it. Changed thermostat with oem ford and was good to go.

 

The only non-OEM thermostat I'll use is Stant.

 

The thermostats in the 5L are special design due to the reverse flow cooling control system design.
They have already gone through a revision for a hang up issue.
You cannot use an aftermarket unit.