I'll first start off by saying that i just did a coolant flush on March 6th. I did it the proper way as decribed in the tech folder. I replaced the thermostat at the same time with a motorcraft that i purchased from the dealer and added a coolant filter. Oil cooler was replaced in Sept. 2009 when the truck had 65,336 miles on it. It now has 83,700.

So today i just did an 80 mile trip, outside temp was 80*F. It was all highway and i was driving 65mph. I was monitoring my temps on my edge insight and my ECT was 187* (seems low when its 80* outside) and my EOT was 203* so thats 15* difference and that is where it stayed for the whole trip. So do you think my oil cooler is fine and my new t-stat is just opening too soon? Or am i going to have to tear into it and replace the cooler again? I would think that my ECT should be in the mid to upper 190's. The hottest my ECT has ever got was 189* going up long hills and would then drop back to 187*. Can you guys help me out and give me some advice?

 

I think your thermo is a little off. Mine is 6 months old and oil cooler 4 months last trip out side temp 75 or so at 70 to 80 plus ects 198 202 and eots 202 to 208. Now slow it down to 65 and 195 ects and 198 eots. I have a stant thermo and they all maybe a little diff

 

It was 91*F over the past weekend. With the air conditioning on
on the highway my 5 month old t-stat holds the ECT @ 190 no
matter what.
It might go to 191 or 188/189 momentarily but it stays @ 190
once it's fully warmed up.

I have the BPD coolers, so my ECT also stayed @ 190 as well.