Oil pump pressure issues...

I am experiencing low oil pressures at operating temperatures. Highway speed RPM's at full temperature, I only see about 15psi of pressure on the gauge. Is this acceptable? Replacing the oil pump is not a problem, but it is not something that I want to do if not necessary. Thanks for the help.

Verify your oil pressure first with a mechanical test gauge. If it is truly low, there is no guarantee that the cause is the oil pump. Could be other things like worn bearings inside the engine.

Agree with cruiser54. You MUST verify before making any decisions.

If you don't have access to a mechanical gauge, many big box parts stores will rent you this tool inexpensively; call around.

The oil pressure spec for the 4.0 is as follows:

*Not less than 13 psi at HOT idle
*Between 37-75 psi over 1600 rpms

Good luck!

Cool I thought I was having issue's with oil pressure but your specs put me in the good zone never less than 20 and never over 60

Birchlake fixed it for ya.LOL.

I replaced the oil pump over the weekend with a Melling pump from AutoZone. Problem fixed. Jeep now builds about 45 or 50 psi while driving and around 20 to 25 psi at operating temperature idle. Job was pretty easy since I have a 4in lift, which almost puts the axle out of the way in order to remove the oil pan. I also replaced the leaking rear main seal while I had the oil pan off. I seriously recommend to anyone that does this to replace the seal at the same time. Installation was fairly easy and hopefully now my transmission will not be covered in oil all of the time. Mainly, I'm glad that the problem was with the oil pump and not wore out bearings in the block.