Low Oil Pressure

[Carl Riederer]

(10-30-2026 )tree98 Wrote:  

(10-29-2026 )Carl Riederer Wrote:  This truck had issues with the factory crank. There is an issue somewhere.

There are different sizes of cummins crank bearings, maybe you have a journal or 2 that are oversized and somehow it got overlooked at the factory and the wrong bearings were installed?? The only way to know is to take it apart and measure everything.

If it has an aftermarket head too it could be hemorrhaging oil badly from one or all the cam bearings. Part of the problem with using all this aftermarket stuff is that now you don't know where to start, none of those parts can be trusted.

We ran it with the valve cover off and didn't notice any major oil flow. This engine had oil pressure issues when the engine had all factory parts. We stopped using Cummins heads years ago do too the valves would pound into the seats in a year and would have too replace them with 150,000 miles. The stage 3 heads fixed our issues with that. We have had problems with factory oil pumps, out of the box also. We looked up the bearing on Cummins Quickserv and put new Cummins bottom end bearings in again. Plastic gauged them this morning to make sure and they are plenty tight. Not sure if the air compressor or if the high-pressure pump could cause the issue.