I have an LQ4 in my Jeep and after a few months of working on it and getting ready for an offroading trip I started it up and noticed the oil pressure was low after it was running for a couple minutes. It was about 25 psi at startup and goes down to about 5psi at idle(550rpm)

There were 2 times this past summer that is got hot and went into limp mode at least once, had issues with the cooling fan. The last time I ran it the serpentine belt came off after a pretty hard landing. It was during a competition so I just decided to run it to the end. Most of the runs were about 3-4 minutes, mine was a bit longer due to no power steering(belt was off) and 43" tires making the tight turns almost impossible but I got it to the last jump and aired it out real good(oops). And then at the end was a huge water hazard that I went through unintentionally.

The motor sucked some water in and would not restart for a bit due to the mass air meter getting wet.

I got it running again and had another event to compete in and broke a rear axle shaft so that was the end of my weekend. I did drive it around the campground a little after that and never noticed the oil pressure being any different from normal.

Now at startup oil pressure it about 25psi, it used to be about 33-35psi and after a couple minutes of running it will go down to 5 or less at 550 idle rpm. If I bump the rpm to 750 it goes to 20 psi.

I did change the oil and it looked glittery to me in the sunlight and the new oil netted no different results.

From what the internet shows is 6 PSI @ 1000 RPM, 18 PSI @ 2000 RPM, And 24 PSI @ 4000 RPM

I can get about 35 at 4000 rpm but why so low at idle? Is my idle too low?

I did clean up the wire harness but cutting down about half of the wires to the correct length and need to do the other half but was running out of time to be ready for our offroad trip I missed this weekend.

 

Here is the Jeep

 

Cut the oil filter open and inspect. But the force tell me your in for a rebuild.

 

At minimum, you're tearing the front cover off and inspecting the oil pump's relief valve. It's probably stuck.

But the fact that you are seeing glittery oil means you are probably already in for a rebuild. Bearing material probably clogged the relief valve which dropped your oil psi which caused even more damage.

 

My engine guy suggested a high volume oil pump and run it until it stops.

I mainly surprised as I did not notice the oil pressure being low before I started it a few days ago. It is possible it was and I did not notice but unlikely. The relief valve would make sense to me but would it cause 25 psi at startup and 5 or less warmed up?

I will get a new oil pump before I take the front cover off, which one should I get and where should I get it from?

I appreciate the help and will update with what I find.

 

How to do this without getting shavings in it?

Nevermind, I cut it open with tin snips.

Now what am I looking for and where?

There is a sludge type substance in the bottom of the can, like a silvery paste.

I don't see anything on the filter media but not sure what I am looking for.

 

Yeah, it can be only partially stopped and still make some oil pressure.

 

There is decent amount of metal in the filter but not magnetic so is it safe to assume its bearing material? Not a lot but if it was gold I would be looking for the source, lol

Maybe a few flakes per pleat. That does sound like a lot after all.

 

Yeah man ur in for a build . Its only a matter of time now run it till it knocks lol. I got pictures of mine I'll show you my valley cover

 

I ordered a melling high pressure oil pump and timing cover gaskets today, already have a crank bolt. Am I missing anything to swap the new oil pump in?

Also been shopping for a replacement LQ4 or LQ9.

 

Your oil pressure should be considerably higher i think your rod bearings have been going out on you a wile and you just getting around to notice it now, of course getting that hot did not help, i believe if you change the rod bearings and oil pump your oil pressure should increase to at list 50 psi at could starts.