Unique coolant temp question?

[TruckNorris]

When I was leaving for work this morning, driving on normal, 50 mph roads, my EOT was about 192 and my ECT was 188. As soon as I got on the highway and got up to about 75 mph, my EOT stayed relatively the same, but my ECT dropped to 182 for just about the whole 7 mile ride to my exit. As soon as I got off the highway and dropped back down to about 45 mph, the ECT rose back up to 188.

WTF? I've never seen/heard of ECT dropping while you're working the motor harder, although I'm also not that experienced with 6.0's or diesels in general. There's no puking, coolant level is just a bit below the MIN line in the degas bottle, but it is the gold coolant (until I change it soon).

Anyone have any experience/knowledge with this?

[2006PSDSD]

What was the temp outside? Sounds like the stat is failing, to me

[TruckNorris]

It was probably about 55 out when I was driving.

[2006PSDSD]

Yup, I'd blame the stat

[TruckNorris]

Good deal. So I take it that I shouldn't worry too much about the temp delta then, unless it returns after I put in a new one, correct?

[Fishermedic]

Yup, replace the t stat and recheck the deltas. ECT should be at 190 when you check the delta.

[2006PSDSD]

Yeah, your ECT should be 188-190 under normal driving conditions, and your EOT less than 15*, but closer to 10*. Also, that speed is too fast to get a good reading on the delta. You wanna be at 65mph, no load, engine at operating temp, and on semi flat roads

[RRF985]

Originally Posted by TruckNorris

Good deal. So I take it that I shouldn't worry too much about the temp delta then, unless it returns after I put in a new one, correct?

That is exactly correct.

[TruckNorris]

Awesome. I appreciate the info

[police251]

I have seen temps differ alot I have not had any problems and dont know what I should be looking for or doing. My EOT is 192 and the ECT will be around 180 ish. I have seen deltas with as much as 20-22 degress different is this not good. I was told that any difference then 15 bad stuff starts it has always been like this.