Lonestar with Cummins ISX 600 giving problems - any ideas?

by toby
(virginia )

Just bought a lonestar with cummins isx 600 horsepower left home to get a load of sod had 40 oil pressure but during the day oil pressure kept getting lower started pulling a mountain eventually it was down to 20 and loosing power finally got to the top of the mountain and the high exhaust temperature system light came on but went off a few seconds later engine temperature was around 215 engine warning light was also on even before I got to the mountain.

Took it to dealership found nothing the next day did same thing oil temperature was around 220 going down the hill first time engine brake didn't work second day it did now they think the dpfsystem needs cleaning 380000 miles on engine the engine works fine until the temperature heats up and the oil pressure starts getting close to 20. it was restricting my power our other trucks have 475 cats and blew me away anyone know what's going on