Sounds like a bad sending unit. As long as you have a good oil level and your engine temp is good your pressure is more than likely fine. As for the driving short distances thing, don't forget that the most ware put on an engine is upon starting it up. No, its not that much in respect to the life of your Jeep, just thought I'd mention it.  

Thanks Yell02.  I am going to switch out the Oil Pressure Sending Unit in the PM Friday.  Hopefully that will rectify the problem.  Otherwise, the only thing left, that I can do, is replace the dash guage and see if that's it... after that I'm not sure what's next?  

Don't want to bear bad news, but I don't see a connection with the overheating and your sending unit or dash gauge. The most typical reason for low oil pressure is worn main bearings on the crank. When you overheated, it may have been for long enough to toast the crank bearings. You can inspect them by removing the pan (which you already did once it appears) and pulling the bearing caps and looking to see if they are scored or discolored. This isn't a trivial job and I recommend getting a shop manual as it has a step by step for removing the caps.

Sure hope it's electrical...

I have the exact same problem, but since I'm a poor college student, I just had to hope that it was the sending unit for a while.  It's been about a year and a half and I've had no problems, other than now sometimes when I start up the damn thing reads no oil pressure whatsoever unless I drive about 10 ft. and turn the key back off and on again while rolling, then it barely registers.  I guess I'll get around to replacing it some day, right along with the damn sending unit for my gas gauge.

-Brian  

Hey Guys,

Thanks for the feedback.  It is much appreciated.

I did replace the oil pressure sending unit and tested the gauge to no avail.  Still having the same problem.

I guess the next thing to do is inspect the bearing as you suggested dingebre.

(Not looking forward to that.)

Will keep you informed.

Thanks again,

- Jesse

I hope you haven't taken on the task of removing your rod caps as of yet. First, a few questions:

1: Is this the first time using this Synthetic oil?

2: Did you notice the oil gauge immediatly after the over-heating incident?

But without your response yet, I would recommend that you remove your oil pressure sending unit, and in its place install a mechanical gauge and run the engine up to operating temp, and see what happens.( some auto parts stores will rent these tools to you) if the mechanical gauge still reads low, drop your oil, and try a conventional lubricant. (fossil oil)

Its been my experience that synthetic oils are far more slippery than that of a conventional oil, they will find every available place to leak, and if this is the first time you are using it, this could be the problem. Just because they have the same viscosity ratings does not meen that they will act the same.

Just for your info,

1987 YJ   286,000mi    Stock258(4.2lt) Worked heads, crane cam, holley carb, chevy H.E.I. distributor, Borla header, no cat, flow master, Old Man Emu 2.5in. suspension , 33" BFG AT KO,

STOCK OIL PUMP IN PLACE!!  I run 20w50 in the winter, and a Straight 50 weight in the summer.

Hope this saves you time and money IRON.

I am experiencing a similar problem.  However, I have noticed that my fuel gauge seems to not read full when the tank is full, not that it has been all that accurate to begin with....I have noticed that if I turn the A/C off, the oil pressure does not seem to 'fall' to zero as quickly or as often.

I am running Mobil Synthetic (10w-30) and have since about 10,000 miles. 

I was going to first install a mechanical oil gauge to see if there is really a problem with something other than the sender or the gauge. 

Vehicle Info:

2000 TJ Sahara - I6, A/C, 5 speed tranny, 76,000+ (currently).  Problem seemed to have crept up about 2500 miles ago.  Vehicle resides in Florida, if that makes a difference.

Keep us posted of what you find out and I will do likewise.

---  Mark R.

Low OIL pressure can be caused by several problems and a few different procedures can narrow down the cause. first you need to check a few things.  If oil pressudre is as low as you say then you need to use your first tool "Your Ears". With low Oil pressure you will hear a clicking or clattering from the Valve train. The engine uses an overhead valve train with hydrauilc lifters opening and closing the valves through the pushrods.  When the engine lacks oil pressure the valve lifters will not fully actuate and do not completely open and expand to remove the freplay within the valve train.  To visually check this remove the valve cover and look for squirting out of the rocker arms the squirting oil happens on every other revolution of the crank shaft.  You can also remove the oil pressure sending unit and with appropriate fittings attack a mechanical pressure guage cheep ones are available at most auto parts stores. Start up the engine and record the pressure reading any thing above 10 lbs at idle is acceptible.

After doing the above and you find that you do have pressure , try replacing the sending unit. If the guage still shows no pressure then the guage may be faulty. To check this ground the wire from the guage and bypass the sending unit. Since the sending unit works by varying the resistance to ground the grounding of this wire should give you a full scale reading.  If there is no change in the reading. use a voltmeter to determine if there is a voltage p[resent on this wire. If none then you have a open circuit. Check if you have a blown fuse and check for continuity from the gauge to the other end of the wire. If continuity is ok check to see if the wire supplying voltage to the guage is around 12 volts. If not electric power is not getting to the guages. Usually all the guages on the instrument panel have the same voltage supply including the gas guage.

If voltage is available and the guage still fails to function then the guage is bad.  I like mechanical guages but feel that in heavy usage off road they have potentially serious problems. typically mechanical guages use either copper, steel or plastic tubing. frame/body twisting can cause a break  in the line, with resulting leakage.  Depending where the failure is located a significANT AMOUNT OF OIL may be lost before it is noticed. Additionally when the problem is discovered the repair may become problematical. No replacement crush-sleeve available or way to repair a cracked line. The only way to fix this is to crush the line after bending it over etc. With a electrical guage usually the failure is easy to fix reattach the wire, splice the wire etc.  If you keep an emergency tool kit with a multimeter in it you can use the meter as a backup pressure guage.  Depending on the pressure available you will see changing voltage readings if you are getting oil pressure and all it takes is a few jumper wires and ELECTRICAL TAPE.  therefore you will still be able to monitor you oil pressure in most cases except for the failure of the sending unit.

Rick L  

Thanks for all the info, it was agreat help.

It turns out my issue was well put in the following article and the situation is strikingly similiar in all regards:

http://www.motorage.com/motorage/content/contentDetail.jsp?id=66740

Thanks again,

- IronHelixx

Thanks for all the info, it was agreat help.

It turns out my issue was well put in the following article and the situation is strikingly similiar in all regards:

http://www.motorage.com/motorage/content/contentDetail.jsp?id=66740

Thanks again,

- IronHelixx