Crazy oil temps

[zman111]

I have an 2005 f250 with new oil cooler, new oil temp sensor, I'm using the edge just as a monitor. At cold start the EOT and ECT are always within a 1 or 2 deg of each other however after the ect comes upto operating temp (192/194) I will see the eot swing from 207 to 165 one minute it says 207 the next minute it's going down to below 200 and still dropping and then will start to climb back up again. No towing no hills can happen while driving down the highway or driving around town. So what gives?

[Rick C]

Very strange. Something tells me it's probably a bad wire connection. Gonna take others to chime in on this one.

[lenzhotrod]

Yes a bad connection or a bad sensor. Computer responds to what it sees only.

[amdriven2liv]

And the ECT and the EOT sensors are the same. You could swap them and see if it does the same in the ECT position.

Of course, after you check out the wiring near the EOT sensor for chaffing, as posted above.