The seal on bypass valve in the oil cooler base has been known to tear if manhandled, and messing up either the cooler or filter bypass valves during the work will cause problems. Did the valve come out of the top of the standpipe in the oil filter housing? Or did you accidentally take the cooler bypass valve out of the filter base when you took the oil cooler housing out?

Cooler bypass valve write-up, but it's outdated in that you can find a new valve for sale now. If you need the spring you have to buy the whole filter base:
WA0UWH - Electronics & HAM Radio Blog: FORD Rant - Oil Cooler Bypass Valve - is a non replaceable part.

You can check ECT vs EOT on a cold start (as mentioned above), they should read +/- 2* of each other.

Shooting the pan isn't an accurate way to gauge the oil temp, it has to do with fluid flow in the pan, it's the same reason fancy transmission pans don't do anything for heat transfer:
https://www.ford-trucks.com/forums/1...l#post10038870

 

 

 

Moving to the 6.0L PSD forum.

Nope. The only way to get an accurate oil temperature is to measure the oil itself. So if you can find a way to stick your IR gun inside your engine somewhere and read a stream of moving oil, you should get an accurate measurement. There is ALWAYS going to be a temperature drop across a barrier. If the surface of your oil pan was 205, I'd bet 238-240 is accurate. I think your sensors are working fine and you need an oil cooler, but I'm not the 6.0L expert.

 

 

The oil pan contains hot oil. The oil temp (EOT) you read is AFTER the oil cooler. It is normal for your oil pan to be 40-50 *F higher than the EOT reading.

I would sure verify your Edge reading.

That said, I am not a fan of VC-9, it can loosen up stuff and plug a new oil cooler.

 

 

If I read this right, you're on oil cooler #3 with the same temps now? They can inspect the oil cooler bypass and the filter bypass by only removing the oil filter and three screws, it's not an invasive job. If they do #4, replace the oil filter base also. It's ~$180 part on pretty much a WAG, but if they're there you're already on the wrong side of $800 in labor to get the cooler out again, might as well replace the base and clean the housing really well.

 

 

You can source just the valve, but if you need the spring or if the bore is damaged that requires buying the whole filter base. We've seen torn valves and that's an easy fix by replacement, but there was one where the valve had ridden at an angle in the bore and was galled. This IS a long shot though, so if you waste $16 on the part don't be upset. IPR makes a backflush valve you can replace the EGR cooler outlet cover with, there is still a chance you have so much crap in the cooling system you're seeing coolant-side clogging still.

Use something to compress the valve cover back down, don't pull it down with the screws. Don't LOSE a screw or spring down the standpipe hole either.

https://www.bulletproofdiesel.com/Oi...p/90100115.htm
https://www.ford-trucks.com/forums/1...il-cooler.html

 

 

VC-9 can do some nasty stuff, I've heard (I'm not a chemical engineer and don't pretend to be one, just read this on the internet) that leaving it in longer than 3 hours or at higher concentrations trace amounts can remain adhered to engine metal and continue loosening debris even after it's flushed out. Some people have nasty systems, and have to go so far as to remove the radiator and back flush it and also replace the heater core.

You can backflush though a special cover over the EGR cooler outlet, it works with a welded cooler installed.:
Oil Cooler Backflush Valve Kit - Gen 2
https://www.accuratediesel.com/6-0l-...SABEgI97_D_BwE

 

Very good info in here. I have a similar issue with my truck, and another thread going too. Do you have any updates?