[Sirikenewtron]

Appreciate the updates on this post with results after changing to the new oem thermostat. Hopefully mine will be here next week and I'll report my results as well here instead of starting a new thread.

As of now I'm seeing 210-235ish freeway driving unloaded and not towing with very very minor hills

 

[Sirikenewtron]

Appreciate the updates on this post with results after changing to the new oem thermostat. Hopefully mine will be here next week and I'll report my results as well here instead of starting a new thread.

As of now I'm seeing 210-235ish freeway driving unloaded and not towing with very very minor hills

Just realized this is the thread I meant to post my results on.

swapped out the factory thermostat for the updated part HL3Z-8575-B
Now coolant temps are pretty much consistently 195-205 usually riding right at 199.
Today I finally got to Test it on the mile long steeper grades up the mountain, before on the same grade I would see about 237° once I got to the top and let off the gas, today I only saw 215°

 

[Sirikenewtron]

Do you mean part HL3Z-8575-BB ?

No just one B

 

[Sirikenewtron]

Put a T-stat on order today. Linky below. I’ll pick up some fresh fluid locally. I have been running between 215 and 220 unloaded at interstate speeds.

More Information for MOTORCRAFT RT1252

After swapping it out with that thermostat you should see about 201° give or take on the interstate unloaded not towing. That's been my experience anyways, it did exactly what I was hoping for.