ISX12 oil temp issue

[dericson]

Had a customer come in saying he’s been having oil temp too high issues. Basically states it runs hot pretty much all the time, most notably on hill climbs. Unit is a super dump. Driver says it’ll go in the red “250F” and beyond. They pull over and let her cool, get back to it. Anyways, oil tstat was changed at some other shop about a month ago. Same issues. States coolant temp never really above 185-190 or so. Oil temp used to run pretty steady at about 200f. So I poke around, coolant looks good. Oil temp sensor looks good and reading proper resistance. Oil level good. Thinking maybe oil cooler restricted or something funky but seems such an odd failure to happen so sudden. Coolant temp sensor reading correct. Ecm
Shows no signs of overheat oil temp faults. Engine protection shows nothing crazy. 190 unit hours oil temp was between 235-245f, 245-257F for a total of 3.5 minutes total ecm time in its entirety. My thinking is, is this thing really hot? Wouldn’t you think the calculated time accrued for actually running hot, on the dash gauge (red temp starts at 250f) and insite would be much higher? So I know the old adage rule of oil temps shouldn’t be 30f def difference than coolant temps etc, but I have heard these engine and the 15’s running pretty warm especially during hill climbs heavy. So took a test drive to monitor the truck gauges and insite actual temp recorded, long story short, insite took a shi#t and the data monitor would not work. We through a oil tstat in the thing before test drive, customer request. 45 minute test drive, trying to load up as best as possible and find some uphill grades, got the thing to 185-190 coolant temps, never no fan engagement, and oil temps about 228 highest. We get back to the shop and all of the sudden 80% of the dash gauges shows deadline. No coolant temp, oil temp, oil pressure, def level etc etc. I initially thought this was a gauge/oem body module issue because ecm never showed anything saying the thing is too hot. What are you thoughts. What have you seen out there for coolant and oil temps, what’s safe and what’s to worry about. Truck took a trip to oem for repairs on the datalink gauge issues but will be back for oil leak repairs (wasn’t significant enough to drop the level that much to cause oil pressure or temp issues). I’m sure the driver will still say it gets hot. Pull the cooler or what? It would have to be super restricted because it ain’t blown. No signs of oil or coolant in each other. Thanks!