I just noticed my oil pressure indicator (is it pressure?) is in the middle of the dial at about 40 when the engine revs. When the engine is at idle, it goes down to 10, almost left end of the dial.

Is it normal? Should I be looking for something?

I checked oil and it is up to level with a good color.

On my GM vehicle, once the engine is on, oil indicator shows a constant value.

Thanks.

 

The cam bearings are worn my 91 is the same way its really nothn to worry about I was told "its a jeep thing" so I haven't really worried about it

 

If that's the true pressure, it's a little low. You should be at ~20 when idling and ~60 when on the gas. But the first thing I would do is verify with a mechanical gauge that you are getting a correct reading because the gauges on the XJ have proven time and time again to not be 100% accurate.

 

^^This^^
Always verify the pressure.

 

Mine has been doing this for the past 200k miles..

 

Always thought about ~15psi idle and 45-50psi under throttle was normal. My old Tj had that from the factory until the day I sold it at 210k. Of course we all know that "exactness"varies...

And certain/older oil senders are just "dummy" senders. My Ranger does that; it's ALWAYS at one point, and never wavers; off or on.

 

That's because Ford used a switch. My '93 ranger was the same. Either it reads "right" or it reads zero.
They got sick of warranty work fixing that "broken oil thingie that keeps moving around", and irate owners who thought something was wrong when the gauge moved. Seriously.
(same reason chrysler buffered their gauge readings through the PCM in later years)

Put a mech. pressure gauge on it before deciding if you have a problem or not. The stock Jeep gauge is approximate, not calibrated that well, and the senders do fail in funky ways.

 

Gotta ask... What brand of oil filter is on the Jeep?

 

NAPA Premium or Platinum - the more expensive one for the XJ.

I am also running Mobile 1 synthetic - car has only 56K miles on it

 

Better fix that some day.

 

I'll probably test it with a gauge to see what the real pressure is. I also have a new sender unit on the shelf.

 

Dont probably test it. You should actually test it. Make sure your engine is working properly

 

We wouldn't want to see you rushing into things..............

 

Where the hell did you come from? Better yet, crawl back under our rock you spammer.