Not ford related but back when i had the Toyota 3.4L. You could take the thermostat and rotated it 180 degrees. There's a jiggle valve on the thermostat. It would drop operating temps between 7-8 degrees. They called it the jiggle valve mod.
I have a 2019 F150 with the high output 3.5 Ecoboost. The only oil temperature it shows is the transmission oil temperature. It doesn't show engine oil temp. In fact, unless you have downloaded Forscan, and modified the ECM programing a bit, you won't even see actual trans oil temps, until the transmission gets dangerously hot. Using Forscan, you can have the trans temps and coolant temps digitally displayed above the analog gauges all the time. I did this mod on my truck. I also have a Reische 170 thermostat, but have yet to install it. I was seeing 220 degree coolant temps routinely in normal driving. Since unplugging the shutters which regulate air flow through the radiator, coolant temps are 10 to 15 degrees cooler. Why the shutters are there other than to keep the engine artificially hot is unknown. When connected, the shutters only open under acceleration, and close on cruise or low throttle. My truck has a 195 degree thermostat as OEM. The reason I've not yet installed the 170 T-stat is I cannot find what triggers the Ecoboost to switch from open loop operation after startup, to closed loop. On most vehicles, coolant temperature reaching a certain point is that trigger. Older Fords made that switch based on time after start only, but I can't find anything about the later models. If the engine stays in open loop continuously, mileage will take a serious hit.Originally Posted by RhondaHondaDoes your Navigator Show oil temp like the newer F-150s do? I'd be curious what the temps were before and after the thermostat swap.