Just bought a 2004 F350 dually 4x4 lariat. Only 62k miles, super clean one owner truck. I am trying to diagnose some issues I bought it with, but here is that details..

Banks "Power Pack " system (inter cooler, high ram intake, exhaust, and IQ screen for all my displays). EGR delete, 4:10 gears.

During normal, unloaded driving in 80-90F weather I'm seeing through the IQ that I'm running around 225F oil temp, 190F coolant temp. These numbers are telling me I have a clogged oil cooler. Before I jump to conclusions and spend big money I'd like to know if there are any other possible causes. Or a positive way to say I need a cooler other than temp readings. I have no codes, and the degas bottle isn't showing the typical oil cooler extreme failures.

Could it it be a bad sensor?

 

Do you have a motorcraft filter and cap. With those temps you likely just need a oil cooler. I would fulsh the cooling system very good and then your ready to switch to elc and not clog up the new cooler. If you want to do the chemical flushes now is the time and change the oil cooler before it ruptures and you have bigger problems.

 

What are the ECT and EOT readings after the engine being turned off for 8+ hours? They should be within 2-3* of each other; that rules out sensor bias.

You can remove the oil filter cap and filter and inspect the bypass valve in the oil filter standpipe. If that's in place that's pretty much it as far as physical diagnostics; to inspect the bypass and drain the in oil filter base you have to tear further in.

But buddy, you probalby need an oil cooler.

 

After being parked overnight, compare the oil, coolant, and trans temps, to make certain they are within a couple of degrees of each other. Sometimes, it takes more than a few hours for the temps to settle.

You want to ensure both are reading correctly.
Your hiway trip with 4:10 gears will cause a bit more load that 3:73, plus if are driving 80 vs 60-65 the temps will be higher, all these factors come in to play.