2000 XJ Oil Pressure Problem

[kylepalmieri]

Today I drove to work and everything was normal with my jeep. When I started my jeep again to go home, my check gauges light came on and my oil pressure gauge was registering nothing. I checked my oil and it was good (although its been more like 5000 instead of my usual 3000 since my last change) I took my chances and drove it home (about 14 miles - no highway) without any problems, everything sounds and runs normally. Once home, i checked out the sending unit and it looks normal. I also checked the wires. When I turn off the jeep I can hear the normal trickling sound of the oil flowing back down (might be coolant though, I'm not sure) and i can see a little bit of oil flowing into the rockers under the valve cover through the fill hole when the motor is on. When I rev the jeep up a bit (2000 rpms) the guage will move up a little bit and the light will turn off but it goes back down once i let off the gas. Does anyone have any experience with this? What should I check next? Any help here would be greatly appreciated. Thanks in advance! 2000 XJ sport 4.0 159,000 miles.

 

[thebrick]

I haven't had any issues like this...I have a 2000 as well...but having read several threads on this (you can search for 'oil pressue' in the forum), I would suggest getting a mechanical gauge to see if your electronic gauge is correct.

If your oil pressure was truly '0'...you can do irreparable damage to the engine...especially bearings.

However, there appears to be a lot of posts here about the oil pressure sending unit near the oil filter going bad. I've even heard one guy say that the wires to the sending unit were 'broke' causing the reading to be always high.

The sending unit has electrical components, so you can't tell if it is bad by just looking at it...there might be some resistance tests you can do to check it out, but not sure what the specs are.

The sending unit would be my first guess as to your low oil pressure reading.

Worse case...you need a new oil pump...

good luck...

 

[Laurent Wagoneer]

x2 on the oil pressure sensor.....

if it was the oil pump, there wouldnt be any flow at all......

Oil pressure sensor is located next to the oil filter..... :wave:

 

[birchlakeXJ]

You know that the gauge isn't working properly if it registers zero oil pressure and the engine isn't rattling. And the most common cause of inaccurate or no readings on the gauge is the oil pressure sending unit (aka: oil pressure switch in some parts stores).

If you want to confirm what your actual pressure is, temporarily install a mechanical oil pressure gauge where the sending unit currently resides. They can be rented from many big box parts stores.

First thing I would try though would be removing and cleaning the connector for the sending unit and if that doesn't work, then the mechanical gauge or just install a new sending unit. I always recommend purchasing this item from Jeep for best reliability and accuracy/mating with your factory gauge. Aftermarket stuff is very hit and miss.

 

[kylepalmieri]

First and foremost I changed the oil. I then took off the pressure sending unit and cleaned it out. It looks like it was definitely leaking a bit. With it off i turned on the motor for a few seconds and it shot a decent amount of oil out. So it looks like I definitely have oil pressure. I then put it back on and reconnected it. The gauge now shows a high reading (around 50 at idle). So it looks like the problem is the sending unit. Right now I'm working on finding a manual pressure tester.

 

[seg501]

I had this same issue with my 99 XJ limited. When I bought it last year the pressure gauge was reading 50 psi and going up to 80 when reving or driving. I then replaced the oil pressure sensor that is located below the distrib cap and the pressure gauge went back to normal. After about 5 hours after doing this, my Check Gauges light went on and the pressure went to 0. I had a garage do a PSI test and it came out normal. So I ended up putting the old pressure sensor and it runs at 50psi and a little above that when driving. You may want to check all of your grounds and make sure they are not rotted out. Also I wouldn't be driving around until you do a pressure test.

 

[sjx40250]

I have the same problem with my WJ!

 

[joe_peters]

Whenever you have indicated oil pressure problems you should hook up a mechanical pressure gauge for the peace of mind.

Get a sender from the dealership or NAPA, stay away from the Chinese parts store chains.

 

[cleburnecherokee]

I have a 1991 XJ Laredo with the same issue, but it comes and goes, sometimes the pressure gauge reads normal, then all of the sudden I can be sitting at a light and the pressure drops to nothing, no valve ticking or rattling so I know oil is still getting where it needs to go so I suspect the pressure sending unit on mine as well. Any other thoughts on this strange issue would be most appreciated.

-Andy
'91 XJ Laredo 4.0L HO

 

[birchlakeXJ]

I have a 1991 XJ Laredo with the same issue, but it comes and goes, sometimes the pressure gauge reads normal, then all of the sudden I can be sitting at a light and the pressure drops to nothing, no valve ticking or rattling so I know oil is still getting where it needs to go so I suspect the pressure sending unit on mine as well. Any other thoughts on this strange issue would be most appreciated.

-Andy
'91 XJ Laredo 4.0L HO

All the same advice on the sending unit would apply to your symptoms.

 

[JAS]

start by changing the oil pressure sender... It is like a 5 minute job and has corrected many XJs with '0' oil pressure.

 

[dave92cherokee]

I recently had the same problem and it's amazing how well a good oil change works and using a WIX 51515 filter with almost 7 quarts of oil running through the system. I went from 10psi at idle back to 25 and just over 40 doing 55mph.

 

[cklaus]

my 2000 did the same thing, It was the sending unit.

 

[tj'sxj]

anyone know the average oil pressure should be? i run between 35-40 at idle, and 40-55 while rolling! 90 4.0

 

[joe_peters]

FSM says minimum at idle should be 13 psi.

Rule of thumb is 10 psi per 1000 rpm.

If you think you have a pressure problem then use a mechanical gauge to confirm or disprove the issue.

And yes, it is probably just your sending unit, buy a good one from the dealer or NAPA.