Hey guys, I have been having issues lately with with high EOT's, decided to flush the system today. ECT average has been 185, never really hitting 190's. Should I replace the T-Stat? Logged run with Torque Pro before flush ECT avg was 185, EOT avg was 215. High was ECT 190, EOT was 221. Largest Delta was 36 degrees. After the flush ECT avg was 185, EOT avg was 195. High was ECT 194, EOT was 208. Largest Delta was 21 degrees.

 

Looks like you need a thermostat first

 

I'm running a 185 mishi TStat. I think 185 ECT IS fine.

But yes, oil cooler is in your future. Run about 1000 miles first if you can. This will let anything you loosened up in the flush to lodge into the old oil cooler. Consider adding a coolant filter, then run 1000 miles before don't the oil cooler.

Others have flushed the oil cooler and gotten good results. However, those results have not lasted.

 

Brian,
Isn't the motor pouring the fuel to it trying to get above 185°... thinking it's still cold?

 

I've seen posted that 185 is fine. These things aren't that precise. My 185 opens at 186 or so. I didn't notice much mileage difference going from my old tstat that ran at 175 and my first mishi that was opening at 195. But the mileage on These things is so sensitive to speed, I'm not sure mileage is a clear indicator either.

So, from my experience with mileage, I'd put the number around 180. However, from people that should know on this forum, 185 is where the fuel dump stops....which is why I said it was fine.

I do know that my old off brand TStat started opening at 165 and jumping around a lot. When this started, I would run a little warm while towing. Changed to the mishi 185, now I don't run warm towing. Apparently my old tstat was so bad, it wasn't opening enough.

I have now exhausted my supposed knowledge on the subject.

 

The PCM looks for anything over 186° to be considered warmed up. Anything less, it's dumping extra fuel to attempt to warm it up.
This is evident on the IDS (Ford diagnostic software) because many of the tests will not run, or go green, until the coolant temp is over 186°f.

Kersey, if your doing the test correctly and the 2 temp sensors match when cold and are not faulty, then it looks like you have a partially clogged oil cooler.

 

Well, there you go. Ya gotta love this forum.

 

Man what great information out of this group! Thanks I will start with the T-stat and see if I see more improvements, I back flushed the oil cooler for nearly an hour and a half, added cleaner and flushed more. I will update after I make the change and post some more numbers. Again thanks!