ISX oil pressure problems

[Therealarw]

Hi everyone,

I got a Cummins ISX15 that’s been having some oil pressure issues. Only thing is I haven’t actually pulled the head off and actually dug deep into it. So the problem before I took it out of the truck was that the oil temperature would rise to 235 sometimes even 245 super fast. Oil temps would get to 235 during parked regens when it was 90-95 degrees outside. When we took it on several road tests it would hit 235 degrees on the temp and then the engine would lose oil pressure all the way to zero and would end up shutting the truck off. We even use a manual guage and it read zero on the road test. So it’s not electrical, my question is when I start pulling the motor apart where should I look? Is there certain oil galleys I need to look at? Do I just need to completely clean out the whole oil system? All suggestions considered because this is my first time dealing with this type of problem in an ISX15.