Kowalski5599

My 98 XJ has 191,000 miles on it, and once the engine is up to operating temperature, my oil pressure drops to a few slivers above zero. Once I give it any gas it will go back to it's usual position between 1 third and halfway, I wonder if this is a sign that the oil pump is failing, there seems to be some oil very slowly creeping out from under the valve cover, so I wonder if that could have an affect as well... Thoughts?

Thunder & Lightning

Mine does same thing & as far as I can tell it's normal. I never Zero out or clatter & it always go up when I bring rpm's up. Small leak valve cover doubt has anything to do with gauge.

DFlintstone

The older/the more worn the engine, the larger the clearance on things including the crank, cam and lifters. Oil gets through easier and hence lower pressure. The Jeep gauge is only so reliable, you might want to check it with a mechanical gauge. Also low idle will give lower numbers there. There was a time a guy might just slap in a $10 set of new rod bearing inserts to buy some time. Also I guess sometimes a new pump helps. I really like the 'advanced search" feature on google.

tjwalker

DFlintstone is right on. For low oil pressure readings, you must verify it as good data = good decisions.

Get a mechanical gauge on there and then you will know for sure.

The spec for oil pressure for the 4.0 is as follows:

*Not less than 13 psi at HOT idle
*Between 37-75 psi over 1600 rpms

cruiser54

While you're looking down around the oil filter area, get the brand name of the oil filter and post it up please.

NPx

Does the engine still seem to run okay and sound okay when it the oil pressure looks low? My '98 XJ 4.0 engine has had "low" oil pressure at hot idle ever since I got it, around 60k ago. Engine never makes unusual noise. As suggested above, if it's a worry then check the actual pressure with a mechanical gauge to confirm.

Kowalski5599

I used to use WIX and now I am using FRAM 6X and castrol high mileage. The engine pretty much runs as it normally does, at regardless pressure. I could have done google search I suppose.

I could get a mechanical one on there. But if this is something the 4.0 does, I guess I'm not worried. It has been doing this since I own it, sometimes it stays at zero oil pressure when I start it (still warm) until I give it gas, then it's fine.

Dan Shook

whats the deal with what oil filter is being used?

cruiser54

Fram is known for having poor anti-drainback valves. This is critical on our Jeeps because the oil filters mount sideway or worse yet, upsid down. This causes your Jeep to start with little or no oil in the filter feeding the bearings air instead of oil. Done repeatedly, bearing damage does occur.
There have also been reports on the different Jeep forums of low oil pressure and the owner's removed the Fram filter, cut it open, and found the internal filtering material unglued and disintegrating.

Check out this link for more info.

http://minimopar.knizefamily.net/oil.../opinions.html

XJinYORK

2001 XJ with 146k miles, started experiencing low oil pressure, then no oil pressure at idle afte engine was hot. Pulled oil sensor, ran a doubled up pipe cleaner through the elbow into the block about a dozen times, and now have 40-52 PSI after engines hot, depending on motor RPM. Thanks for the information.

PatHenry

I had the opposite problem - my oil pressure was reading high. I figured it was the sending unit, but after verifying that it was actually high with a mechanical gauge, I did a little research and since I had a Fram filter on it (I had no idea they were that bad, even the so-called "premium" versions) I swapped it out for a WIX filter. Sure enough the oil pressure started reading in the normal range and WOW does my XJ like that WIX filter. The engine seems to run significantly more smoothly than it did before. I'll never buy a Fram filter again.

Tatiana Velez

Hi everyone, I hate to highjack this post but I’m new on here and have no idea how to start a new thread if anyone could help me out that would be great.
So I noticed this morning that when I’m driving and I go over any hole or bump in the road my rpms start jumping, my speedometer does the same, and the oil pressure gauge drops to L and then it starts shutting off so I have to pull over, turn it off and back on and then it’s fine until I hit the next bump. I have an 04 grand Cherokee, last oil change was about a week ago.

RocketMouse

Hi and welcome to the forum.... above is a screen shot of what you need to do to start a new thread on your own.
Simply click on the appropriate section from the main forum page where you log in. And part way down on the left you will see the blue "new thread" button. Click and the rest is self explanatory. Hope that helps. Any questions just ask.
As for your issue... could be a few things... start your new thread and you should get good response right there for it.

IJM

IIRC, the NAPA Gold filters are the same as the WIX. Just a different label. That's what I use (along with Rotella T6).

PatHenry

This was actually the first time I've used a WIX filter, on my previous DD I used Mobil-1 oil and filter since I bought it new and wanted the best. Since then I still prefer the Mobil 1 oil since I've had great results with it but filters could be whatever Wal-mart had that seemed good.
I hadn't thought much about it assuming any name brand was "good enough".
I got the WIX since it was on the list of recommended filter brands, the small but close to home parts store I only use for emergencies had it and I wanted to get rid of the Fram.
I really was shocked at how big a difference it made, or really how terrible the Fram was. I'm glad I only had that filter for a few hundred miles. Who knows how much damage my engine might have suffered due to the restricted flow (assuming that was the problem)....