[ShadowEye571]

Hi all,
Just curious as to what the oil pressure should be on an 01 Cherokee stock. I use rotella 15w40. While driving at 1500 rpm it stays above the 40 mark, one mark. At idle it only drops one mark to the left. I searched the forums and basically got that the 4.0 jumps a lot. However some jeep owners were saying they usually get around 16 -28 psi at idle. My oil pressure gauge has never been that low from what I could remember. It has only changed when I start up and drive and give it gas to move on highway when leaving work it goes to the 80 mark then drops and stays around the 40 mark. Engine runs fine but still chasing a few problems.

 

[Ralph77]

If I am understanding you correctly I wouldn't worry to much.
The specs say 13 pounds and while they don't specify this I think they mean at a very hot idle.
Cause IMO that is what you really care about.
And the what I think is higher pressure you are seeing might be cause of the heavier oil you are using.
I use convention 10W 30 in the warmer months and 5W 30 in the colder months so....
While the gauge on my '00 XJ always read fine I was curious about how accurate it was.
So I finally got around to putting a mechanical tester to her.
But I also plumbed in some fittings so that I could run the tester and cluster gauge at the same time.
I was curious about how they compared to each other.
My pressure at a very hot idle with about 165K on her and the cluster gauge pretty much read the same.
The fittings I plumbed in to do this too.

 

[ShadowEye571]

I figured as much, I used 10w-30 for my first two oil changes but don't remember the pressure being different. I remember thinking if the pressure is the same or around where it was I'm good when I put in the rotella 15w40. So I was curious but I forgot when heading home last night I forgot the below 40 was hot idle. It stayed above 40 at the first mark even while idling until the engine got to correct temp.

 

[kohlerbruce890]

I figured as much, I used 10w-30 for my first two oil changes but don't remember the pressure being different. I remember thinking if the pressure is the same or around where it was I'm good when I put in the rotella 15w40. So I was curious but I forgot when heading home last night I forgot the below 40 was hot idle. It stayed above 40 at the first mark even while idling until the engine got to correct temp.

I live in Az. 110° this week. Last night bought 20/50-w. Run Straight-60 in both Harleys! (Air Cooled). When you should Worry, is when your Oil Pressure READS-0