Okay, so i am currently running castrol high mileage 10w30 oil, but it did this before i started using this oil. No change, i just always used this oil in all of my vehicles.
Once the truck has been running for a good while and it is at its full running temperature, the oil pressure drops low at idle. It usually will hang on to the last line before 0, so i'm guestimating that this is 10psi. sometimes it looks like 9, but it could be just the angle im looking at the gauge. It NEVER goes below this point. Although, once i accelerate, it rises again, back up to 40/50, whatever is normal. Also, when it is at this low psi, i can hear like a pup pup pup pup (sorry, i dont know how to describe it better) inside the cabin coming from the engine. My chrysler sebring used to make the same pup pup pup noise.
i am definitely concerned, but everyone is telling me that its SUPER common for jeeps to run this psi at hot idle and that the noise that im hearing is normal as well.
additional info: doesnt burn any oil, doesnt use any coolant, coolant is super clean and green, and oil looks absolutely fine.
I only have Renix gauges to look at so correct me if I'm wrong about the later models. My gauge has four lines - 0, line, 40, line, 80. Both my rigs idle (hot idle) run at the first line, between zero and 40...so I would a$$ume, the first line is 20psi...or 19 in your case...and runs at 40 to the next line...aka60 psi.
Sounds perfectly normal to me.
As far as the pup, pup, pup noise...I dunno.
1990 XJ Laredo - White & Chrome
1988 MJ Pioneer - Metallic Green and Black