Hey...my 1997 xj has a weird thing going on with the oil psi. It remains on 10 psi when warm and idle. When driving it is between 38 and 45...car has no sounds and drives perfect...what could it be?

 

What could it be?

My 98 Cherokee! I have a new ATK remanufactured engine in mine. Same observation as your. About 10 PSI at a hot idle, and about 4-45 PSI at anything over 1500 RPM. No noises, ticks, or overheating.

Assuming you don't have an oil pump failing or clogging issue, oil pressure is a function of bearing clearances, so I suppose we have a bit more clearance than others. It hasn't bothered mine, so I've relaxed about it.

 

10 is a little on the low side, 13# is the recommended minimum at idle, but the 3# difference is as likely to be metering error as anything else. The gauge isn't that accurate.
I'd put a mechanical gauge on it and see what you have. If it's over 13 at idle and rises nicely with RPM, I wouldn't lose any sleep over it. It's normal.

 

Even at hot idle mine never goes below 30. above 1600-ish its always 60-80.

 

What kind of oil filter are you running?

 

Wix filter and 10-30 T5 Rotella

 

How many miles do you have? I don't recall mine run that high even when I bought it brand new back in 2000.

 

I will rent a mechanical gauge this week. The sending unit for the oil pressure switch is brand new as well. I am running 10w-30 and a Napa gold filter. Would running say 10w-40 help raise pressure?

 

137k. Some time I'm going to hook up a mechanical gauge to see if it's way off or even close.

 

If your gauge is accurate, that's high.

 

I believe the stock pump starts bypassing back to the pan at 75#

 

Oil pressure sending unit likely.