I replaced my oil sending unit 65,000 miles ago when the pressure dropped down to 30 pounds. The new unit came up to around 55 now I drop to 30 at idle and 40 driving down the highway. Do these sending units go bad a lot, I'am ready to go to a mechanical gauge has any one done this? I have 280,000 on the truck could the oil pump be get weak?

 

Was the sender you used 65k ago an OEM?
65k miles is pretty good if it wasn't.

I've never heard of an oil pump going bad on one of these engines.
I'd hook up a mechanical gauge even if it's just temporary and see if it agrees with the dash gauge.

 

I would be curious to see your readings with a mechanical gauge. I always ranged between 30 to 50 at the factory dash gauge depending on temp and speed. With motor hot, on freeway, reading is right at about 40. I believe I have the factory sender in my truck with 86k miles on it. Anyone know what Dodge says is their normal range of expected fluctuation on the factory gauge?

 

All I know is 10 psi is the minimum acceptable pressure.
Seems way too low to me but that's Cummins' specs.

 

I guess that would be when a check engine or oil light of sorts must present itself.

 

I bought that sending unit at Napa.

 

Replace with one from Cummins before you freak out......( or another NAPA one, just know they don't have a history of lasting. )

 

i haven't replaced mine the wires get loose there may be a vibration or two under the hood,and my sensor isn't great.but i put a mechanical one under the hood.there is a 1/8 pipe thread plug in the oil filter head and i have a fairly accurate reading i check the oil pressure under the hood at least once a week,the one in the dash just reads irratically.but the next time i'm at cummins i have to pick one up,i've learned my lesson with aftermarket filters and sensors...cheers good luck.