I have a 2001 xj sport with the 4.0. It only has a 105,000 miles. A few days ago I was out running errands and after driving around for a while I looked down while sitting at a stoplight and noticed that my check gauges light was on. I checked the gauges and my oil pressure gauge was at 0!!! I immediately began to accelerate as soon as the light changed and the oil pressure went back up to about 30 p.s.i. On the rest of the way home I watched it close, and at stoplights I saw the needle at 10 p.s.i. In one instance I watched the needle jump from 10 to 0 in an instant, no slow crawl to 0, just directly to 0 instantly. This made me wonder if the gauge was just acting up. It seems to run fine cold. Running hot there seems to be nothing wrong other than the oil pressure gauge telling me otherwise. Has anyone experienced this? Any info would be appreciated

 

I bought a 98 about a month ago and it would only be about 35-40 driving but at idle at a stop light it will go down to 10,7, 12 around that area and I've gotten a 0 or two as well. Change the oil to some 10w 30 or 10w 40 that might help mine does better now

 

An important question for you. Are you using any coolant? Having to add to the reservoir? You have an 01, which has the infamous 0331 cylinder head, which has a casting defect between cylinders 3-4, which can result in a crack in that head. That can result in coolant mixing with the oil and trashing the engine bearings resulting in low oil pressure.

I am NOT saying that is what is happening with your engine. I just want to be sure you are aware of the head issue.

What I would do is this. Get a hold of a MECHANICAL oil pressure gauge. They can be rented from many parts stores. Temporarily install it where the oil pressure sending unit resides. Compare what the mechanical gauge reads to what you see on your dash. You may just have a bad oil pressure sending unit.

Good data = good decisions.

Good luck and let us know what you find!

 

Make sure you verify your oil pressure as tjwalker said. I had the same problem when I first bought my 98 XJ. I changed the oil and filter. and it went to the normal range. What brand of oil filter do you have on it now? If it's a Fram. Get rid of it. That's what was on mine. You do not want to use the fram crap. They do have the tendency to cause oil pressure problems.

 

Just agreeing with what others have said. If you have a fram ditch it. I noticed a good jump in PSI when I switched to a Mobile 1 filter. Check your pressure with a mechanical gauge and report back with the numbers.

 

My first instinct is to check the sending unit. My XJ was doing the same thing and I replaced that and it went back to normal.

 

But RTorrez1, the Fram people have always spoken highly of you....

 

Its not using coolant, just checked and its still full. The family mechanic looked it over a few moths ago. I have since taken it on a few vacations. I was afraid you were going to bring the head issue up. Are there any good threads that explain how to look for that number? And where exactly is the sending unit? I may have found it, is it gray and has two wires coming from it?

 

LOL!!! I dont use a Fram, but it is some off brand

 

That's only because I used to sale them. LOL

After checking your pressure with the mechanics pressure gauge change out the filter. Use Wix or Mopar Brands. You can pick up a mopar filter at Walmart. Once you replace the filter with the above brand filter and I bet you will see a difference. Unless you have another problem. Then we can go from there.

 

my MOBIL1 oil change with a MOBIL1 filter fixed my problem (FRAM was on there before...)

MOBIL1=expensive goodness

 

Does anyone else here think this was the right reaction?
Myself, I would have shut it off and at least pulled the dip stick to see if there was anything in there...
(My motor is more important then causing some traffic)

 

I love oil filter wars.

Check this video:


My personal preference for large capacity oil filters for the 4.0 horizontally mounted oil filters:

Napa Gold 1515
Wix 51515
Purolator PL30001 or PSL30001 for syn oil use
Motorcraft FL-1A

I've used all of these and found no real difference in performance.

 

Mobil1 filter here!

 

If only there was a way to combine them with oil weight and thermostat temp. wars we'd have quite a show.