09 Cummins ISX 435 ST Low Oil Pressure

sounds like it could be the oil pressure regulator.you need to drop the pan to replace this. Ashley it's usually recommended that you replace it when you replace the oil pump

 

ISX engines are known to be dirty engines with high soot build up in the oil that plug oil filters. Did you see your pressure come up with the fresh oil and filter?

 

I know this sounds funny but are you using any amount of radiator coolent

 

Leaking EGR valves can cause the engine to soot up the oil. The low oil pressure is usually temporarily corrected by a filter change. Usually leaking EGR valves throw EGR temp too high, Turbo inlet temp too high and can cause excessive regens. Usually the first thing to do is make sure your EGR differential pressure sensing tubes are clean, and that the venturi pipe is also clear so the EGR differential pressure sensor is reading correctly. This is normally a good time to also clean or replace the intake manifold pressure sensor for being plugged. To check for a leaking EGR valve you need someone with Insite and perform a forced regen. You need to watch the EGR differential pressure during the regen. It should be less then 0.3 inches of Hg. The EGR valve is commanded closed by the ECM during a regen, but if the sensor is reading more than 0.3 that means it is leaking exhaust gases back into the intake.

 

Also might help a little to be sure and use the longer oil filter. They make a short one and a long one and sometimes the oil change place will just use the short one if ya don't tell em.

 

I read on another thread that the timing might be off, causing the oil filter to plug up sooner.

 

Yes, this is another possibly, low power and poor fuel economy are usually the primary complaints with that.