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GreenerThanYou · 06-14-2009, 08:44 AM

Hey everyone, what is the "normal" reading for the oil pressure gauge on a 2000 XJ 4.0? Everyone else I know who has one has always had the gauge just to the right of 40. Mine was when I got it, but now it;s all over the place. When I start the truck it peggs out to 80 right away, then it eventually goes down but only to about halfway between 40 and 80. When im on the gas, it goes up, but i've never seen one thats all over the place like this. Truck seems to run and drive ok. maybe an issue with the gauge itself? My 87 Trans Am had a problem with the oil pressure sending unit. So any ideas you guys have would be appreciated. thanks!!

McRay · 06-14-2009, 09:34 AM

My problem with oil press erratic was ground problem. Removed sensor cleaned treads check grounds at firewall. Fix problem- could also have bad sensor.

Evol · 06-14-2009, 10:51 AM

I have somewhat the same problem except my pressure is lower than 40,I have a slight leak somewhere and when I fill my oil to where its supposed to be it stays a 40 till it leaks out.
Not to post swipe but anyone know how hard is it to change to main seal?

So you might have to much oil,not sure if thats correct honestly i'd like to know myself?

GreenerThanYou · 06-15-2009, 08:12 PM

just looking for what anyone else's gauge reads or any similar experiences. c'mon guys where are ya?

**96sport** · 06-15-2009, 11:23 PM

mine fluctuates from about 25-80, it just depends wether or not it's hot or cold and blah, blah, to blah. I think that it's just the way 4.0 run after awhile because this has always been my experience with them.

Ohh and it runs smooth and doesn't miss a beat.

**2slw4u** · 06-15-2009, 11:30 PM

mine use to shoot way past 80 and was all over the place, i didnt care because the engine was running fine, what happened is the oil pressure switch(sensor) went out and i leaked about 2 quarts of oil in a night. i replaced it never had any more problems.

**2000XJ** · 06-17-2009, 01:15 AM

During acceleration I'm usually over the mid point (can't remember if that's 40 right now). If i'm stopped, I know it's down under mid.

aurichbb7 · 06-17-2009, 11:50 AM

x2 on what 2000xj said

Justin99XJSport · 06-17-2009, 12:40 PM

x3 on that. I kept going back and forth on whether I should replace my sensor as I read this thread lol. Still not sure.

95cherokee · 06-23-2009, 08:11 AM

mine did that and i replaced the sending unit and now it stays past 80 so i said screw it and just drive it im kinda waiting to replace it with another motor anyways

McRay · 06-23-2009, 09:55 AM

My oil gauge on my 2001 Jeep Cherokee runs 40 to 45 psi using 10w-40 motor oil at 85 to 90 degree out side temp - Jeep engine temp runs 195 to 200 degrees 4.0 inline 6

mntnst8xj · 06-23-2009, 08:42 PM

Mine runs at 60. Too much oil can cause it to fluctuate as well as too little. Also check the connector itself. The pigtail that the sensor plugs into can wear out and cause your guage to go crazy if it is not a solid connection.

GreenerThanYou · 06-27-2009, 10:10 PM

hey thanks guys sorry it took me so long to get back to you ive been on much needed vaca. so its at the shop now, and i will hear whats wrong with it on monday. will update when i hear about it. thanks for all the help and your own experience. now i dont feel so bad about driving it because it still runs like a champ.

powersb · 06-29-2009, 11:21 PM

On my 2000 xj its always read ad 80 even when you first start it up, i replaced the sending unit and now it reads at just over 40, usually between 40-45. so i say try replacing your sending unit but as far as i kn there's always been a problem with jeeps and oil pressure sending units.