I'm new to the forum, but I've been digging around on here for a few weeks. My 98' XJ is getting low oil pressure at idle and above 1600 rpm's it's a little above 42 PSI. To me, it runs and sounds fine. I don't notice a loss of power or anything of the sort. I replaced the oil pressure sending unit, changed the oil (Castrol GTX 10w30), and oil filter (Wix). I fired it up, and I was still getting low oil pressure, but it wasn't hitting zero or giving me the check gauges warning. At warm idle, it is pretty consistently right around 10 PSI, which isn't hitting the 13 PSI spec. I went ahead and had it checked out by a reputable mechanic in my area. He hooked up a mechanical pressure gauge to it and verified that my dash readings are indeed true. He said he's hearing some knocking in higher RPM's (which I do not notice) and that the bearings are most likely going bad. My question is, roughly guessing, how many miles can I squeeze out of this thing? I don't drive it hard and don't really intend to. Other than making sure I do oil changes when I need to, are there any things I should be doing to try to prolong this thing for as long as I can?

 

Low oil pressure usually means worn bearings, as your mechanic said. It's hard to say how long it will last but if it were me, id get to those bearings as soon as possible. My 92 did the same thing on the way to obx and it was not pretty. I had to constantly let it cool off and drive it lightly (which is no fun on the sand :P). Replaced the fuel pump that was shot and drove fine after that. From what your'e saying it can wait a little bit, but I wouldn't wait too long. Good oil won't do anything if it cant get where it needs to in your engine. Hope this helps.

 

If spec is 13 and you are still seeing 10 psi, I dont think you have an emergency here. I didnt see how many miles you have on your rig. I have a buddy with an 88 that has 320K on his motor. Same deal. Sounded just fine running but the gauge read about 5 psi at idle. He pulled the pan and the rod bearings were worn through the copper. I see why these things eventually throw rods. He put in a new oil pump and rod berings, brought his PSI up considerably and the thing is still running great.

 

Have you tried using 10w40 or maybe 15w40 a lot of people use 15w40 rotella maybe this oil will help you oil pressure .

 

oh you've done it now...everyone take cover extrashaky is incoming!!!

 

The reason wise folks will recommend getting it dealt with is because if the oil is getting out of the bearings to easily (which low pressure suggests it might be), then it is -not- getting pushed to other places as much as it should. Bearings do take some time to fail completely (but there is no guarantee of this), but in the meantime if anything else is getting oil starved you could end up with a much bigger problems and expense. And of course, if other areas become oil starved, they may fail abruptly, defeating any time you bought by putting it off. None of this is guaranteed to happen, but can happen.

Did your mechanic offer a quote for doing the bearings?

 

My 1992 XJ has about 5PSI at hot idle and 20PSI maybe at highway speeds. Been that way for almost 10 years now. Verified with mechanical gauge.

I even replaced the oil pump with the Melling HV one and bashed the oil pan to make it fit. No change really.

Just change the oil every 4K miles with whatever the manual says for your temperature where you live.

Don't worry about it. It's a 4.0.

 

He did not. I'm having trouble finding a single reputable mechanic in my area that will do a rebuild of any kind. I'm also not able to find a single reputable mechanic who will swap a reman that I personally find and buy. They aren't willing to do something that costly and not be able to warranty it. I don't have the time, space, or know how to do something that major.

 

I'm not sure how to reply to multiple quotes. I greatly appreciate all of the feedback! My plan is to drive this thing until it doesn't drive anymore and figure out something from there. I just wanted to see if anyone else out there had been driving their XJ's under the same condition so I wouldn't feel so alone haha.

 

Almost 24 hours and he still hasnt showed. My faith is dwindling

 

He's actively making his case on 2 other threads. He can't be everywhere at once!

 

LOL It looks like this one has flown under his radar so far. I was running 10w30 in my 240,000 mile 4.0 and my oil pressure was similar to what the OP posted, it was about 40-45 when driving and at 8-10 psi at warm idle, which I don't think was really hurting anything. I switched to a 15w40 diesel rated oil and it raised my oil pressure 10 psi all through the rpm range, my engine also has less lifter tap than it did before, and we recently had a few weeks where temps got down to 0-10 degrees at night and didn't get above freezing in the daytime and I had no issues with cold starts.