He already checked the level and put a oil pressure tool on it and confirmed low pressure lol

 

Well, parder, it seems like you didn't learn everything in your 35 years.

When cold, the worn main bearings can allow the oil pressure to be near normal. As the engine warms up, they expand enough so that the clearances open up. This allows the oil pressure to drop.

Only when they are severely worn will you have a knock. But before that, a symptom is lower than normal pressure with a temperature rise. Also, a spun bearing doesn't usually spin gradually. When it does it near instantly, you will get an instant oil pressure drop.

Personal experience with 2 different engines. Ford 289 and Jeep 4.0 Confirmed with teardown and rebuild.

Incidentally, adequate oil pressure is 10 PSI per 1,000 RPM after warmup.

The OP could also have a clogged oil pickup screen from junk in the lower pan. At idle, the stuff falls away from the screen. When running at higher RPMs, the stuff is drawn into the screen.

 

plenty of oil ,ive had the vechicle for the last 15 years it was completely stock when i got it all the buzzers were still connected ,have had valve cover off and oil pan with in last three years motor is very clean in side .same thing happens with my manual oil pressure gauge installed.

 

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reading and unsterstanding a forum members problem will help in solving it ,answers can be more usefull when this is done partner

 

Oh, I did read and understand. You did get answers and suggestions. Whether or not you choose to believe them or follow them is totally up to you. It's not my Jeep that is broken.

Maybe you should take it in to an expert. Sounds like an useful suggestion to me.

 

you seem to start and end all you replys with smart *** comments i would prefer if you keep them to your self im looking for suggestions to a oil pressure problem that has never been posted on this forum before partner, member post problems here to help each other in finding the answers not get insulted .you might want to seek some professional help your self with your problem

 

Wow Freegdr, you have enough troubles without the negative help eh? Any chance a bearing could have spun, what conditions were you driving in at the onset of the low pressure? although as I understand it you could see it dropping. I expect a bearing spun would be a more instantaneous failure, in my experience. Alternatively, could there be a problem in the pan or at the pump pickup? Could the pickup tube or the strainer have become unattached from the pump? Be interested when you find a resolution, do appreciate and value your insite and postings in the paste when others needed help.

 

that member does seem to have a problem all his own, the problem occured sun morning about 15 miles out of town xj running fine no rise in temp nothing just slowly started dropping ,i pulled over thinking some thing went thru my pan or oil filter split .Oen the hood every thing was fine so i checked the oil all is good start back up normal 40 psi start driving starts going down again left running open hood no ticking no nothing ,just to be on the safe side towed it home put on manual gauge took for ride did it again. im puzzled thinking either pick up tube problem or oil filter some how causing the issue .im off work tomorrow she going on the operating table at 8am bought new pump,oil filter and oil sending switch today .

 

Explains probably why I saw that post with your jeep going up on the trailer, never realized how built she is, awsome XJ. Sounds like you have the parts to operate. I have had customers bring in oil and hydraulic pumps wanting to know if I can rebuild. I can't help them with that, even if I could recondition the interiors the expense is more than buying new off the shelf, anyway I was surprised on how very little wear was in the faceplate of a 45 yr old hydraulic vane pump yet it was failed, looked and felt like maybe couple thou. of wear lines. Your probably taking the correct approach in some internal investigations. I live rural and usually get parts and prepared to replace them when I am in there anyways, don;t have to go back to town and when I close her up I know the guts are good and I won;t have to redo it. Good luck, nice rig.

 

i learned along time ago get all the parts b4 you start what you dont need you can either put on the shelf or take back i will post up what i find

 

Ok freegdr, I dont know why I saved this thing all these years. Mabe it was for you. Just above your oil filter is a plug. The thing it plugs into is what (I believe) reads your oil pressure. It is part plastic that is molded to a metal thing that screws into your engine. I have broke off the plastic part. Oil flows through this (the metal part) and pushes aginst a plastic film. In the pictures is the metal part I have kept. The orange part is the plastic film. Oil come in through a hole in the threads and pushes on it. My aftermarket one dosent read a pressure all the time. Comes and goes. I have driven 1000's of miles without an oil pressure reading on the dash. Sorry about not having technical names for these things as I am not a mechanic.

 

that the oil sending unit must be like a diaghpram in them to trigger your light on the dash never new there was a plastic pc in them like that i have used a manual gauge in the hole where the oil sender screws in and still the oil pressure drops the same thanks for saving that for me to see now i know how the switch works

 

all day long im thinking what plastic bubble you were talking about thought xjs had a special thing no other vechicle had lol

 

So the oil sending unit is just for the light? When this happens to mine the light does come on and the needle goes all the way down. And some times it will come back up. But mostly I just turn the jeep off and then back on and it works.