Another temp delta thread.......

[cRaZy8]

Found a few threads that seem to match my symptoms.

I installed a new oil cooler 2.5yrs ago.
I have been running Rotella EC1 for about 1.5yrs.
Flushed with Restore before the switch.
I think my one year of MC Gold is catching up to me.
I change my coolant filter every other oil change as well.

Similar thread:
Normal Range for a 6.0's deltas

Around town, I cant really get my temps above 190*, EOT or ECT.
On the highway (did a 120 mile round trip yesterday), unloaded besides some tools in the bed, 60* ambient, my ECT would fluctuate 178-184*.
EOT stayed damn steady at 192-194.
Most of the highway run was pretty flat, a few minor hills, and didnt romp on it at all. Stayed right around 65-70mph the whole trip.
Shortly after the highway run, EOT drops within 5* of the ECT.

Not so sure I have an issue?
Opinions?

I finally got that bucking issue fixed with the intermittently sticky IPR, and now this........

[Tuscany]

Replace your thermostat it sounds like it failed open. You should easily be able to get ECT up to atleast 192*.

[03XL6.0]

What he said. Sounds like the t-stat is staying open. Mine does the same thing. I have one here just need to stop being lazy and put it in lol

[nylyon]

The ECT temperatures are too low. If you were seeing maximum of 184 ECT and 194 EOT, there is reason for concern. While officially your ECT needs to be 190 for an accurate test, I would anticipate the EOT climbing as well once you raise the ECT.

If it were me, I would plan on changing the coolant with fresh ELC when changing the thermostat and in the process reverse flush the oil cooler hoping to dislodge enough to put you back into a comfortable range. If you'd like, you can borrow my oil cooler reverse flush adapter.

[F250SixOH]

Replace thermostat with OEM then retest.

[cRaZy8]

Motorcraft thermostat replacement installed.
My delta is now less than 3*.

I did some around town driving today with a couple short highway runs, less than 2 miles.
ECT never went above 193*, EOT stayed pretty much solid at 192* all day.
I even had to tow a 32' Intrepid with twin 250's across town, they both stuck within 3* the whole time.

The thermostat I pulled out was a different design. Not sure what brand it was, but it was noticeabley different. Different size springs, disc, etc.

[cRaZy8]

Motorcraft thermostat replacement installed.
My delta is now less than 3*.

I did some around town driving today with a couple short highway runs, less than 2 miles.
ECT never went above 193*, EOT stayed pretty much solid at 192* all day.
I even had to tow a 32' Intrepid with twin 250's across town, they both stuck within 3* the whole time.

The thermostat I pulled out was a different design. Not sure what brand it was, but it was noticeabley different. Different size springs, disc, etc.