Stumped - Low oil pressure

[jeepguy97]

My old Wrangler amongst many of its problems also had 0 psi of oil pressure at idle. I replaced the pump and mains with no luck. I then replaced rods, still no luck. I then figured it was the cam bearings and started running HD40 weight oil so the pressure stayed up. I sold that jeep at 116,000 miles in that condition. My buddy who now owns it is still driving it around at 200,500 miles with no work done to it. He runs 30 weight oil and the pressure hovers at 3 psi at idle. HE says he will worry when it makes noise..... :dunno: If I would have kept it the motor probably would've seized up...just luck I guess.

That said, being that you did have a coolant leak, I would say it is the cam bearings, however iof it is earing related why didn't the pressure stay up at least just a little with heavier oil? I would say that if you know the pump is good, put some heavy oil in it and maybe some STP and see if it helps at all. If it doesn't I don't see how bearings could be the problem unless they are completly gone......

 

[Dirt]

hey man, I haven't experienced this prob but one of the other guys said it do a manual oil pres test by removing the sender and installing an oil pres gauge it sounds like you know what your doing. with the bottom end rebuild and all. but I just want you to be sure it's not electrical. Good luck with the headache. DIRT

 

[bwickett]

I had this exact problem about two or three months ago and you probably found my thread. I just didn't have time to mess with my daily driver working 50 hour weeks so I took it to a mechanic that a bunch of people recommended. I had the head milled, a valve job and put in a new oil pump. He justified the oil pump by explaining to me that since water doesn't compress, all of the water getting pushed through the pump took its toll on it and that was part of the low pressure problem. It sounded reasonable enough. Anyway, the fix worked; I've put on about three thousand miles since and have had absolutely no issues. Good luck!

 

[bwickett]

One more thing... I went through the other simple tasks that have been mentioned beforehand. Changed the oil pressure sender, oil, filter, etc. so my situtation definitely was not some quick fix like that.

 

[er0080]

jeepguy - my thoughts exactly; those cam bearings must be awfully bad to let 20w50 by (if it is infact the cam bearings, that is). I just hope the block is not cracked near one of the oil passages!

dirt - thanks for the info, that was one of the first things i tried. I actually ran the mechanical gage side by side with the electrical sender and the readings were within 5 pounds of each other at all times. At this point i wish it were my sender!

bwicket - oh yeah water is definetely not a good lubricant, that's why i was surprised to see that my oil pump was in such good shape. I replaced it anyway cuz it was so cheap.

I'm going to be pulling the motor either tomorrow or friday, and I'll be sure to post my findings over the weekend. If anyone else has any input into this, do post! I'd greatly appreciate any input that you may have

Thanks.
Eric

 

[er0080]

richp - aparently I had skimmed past the bottom part of one of your posts! did you say your s10 had over 680k miles on it?! was that the 4.3?

 

[er0080]

1234

 

[RichP]

richp - aparently I had skimmed past the bottom part of one of your posts! did you say your s10 had over 680k miles on it?! was that the 4.3?

2.8L

 

[er0080]

well i filed a complaint with the NHTSA today on their website, and lo and behold, there were probably 10-15 other formal complaints filed there from other owners describing very similar problems. Although I doubt that it would help at all, i suggest anyone with these problems should file a formal complaint there as well. It takes like less than 5 minutes to do, and who knows, maybe you'll come across something else that you've been having trouble with while perusing though the 386 aother complaints that have been filed for the 2000 XJ! It's a real interesting website to checkout at the very least. they have TSB's, recalls, and complaints there as well as tire recalls and aftermarket part recalls as well.

One thing I did notice while I was there - this problem seems to be much more prominent with the 2000 XJ's. I didn't see any complaints from 2001 XJ owners with the cracked cylinder head problem at all. I wonder if DC did do something to improve the 0331 cast between these two model years "behind the scenes".

Eric

 

[UNCC_99XJ]

hmmm....interesting thread this is. I have a 99 that was built in September (IIRC) of 1999. Do I have the 0331 in mine? I have 65K on it, with no pressure problems at all. Engine runs great (minus the skipping from tired spark plugs)

4.0L and all that other mess...lol.

 

[er0080]

you should have the 0630 heads in your XJ. I think only the ZJ's in 99 had the 0331 heads. Check the cast number. It is located on the driver's side top face of the head along the edge where the valve cover mates with the head.

Eric

 

[Creighton]

well. i got a guy who will sell me a 2001 4.0 for 400 bucks (the motor). I'm gonna check my motor out tuesday and see if me and my mechanic can't put our heads together and find a solution.. i got a sneakin huntch its gonna be the cam seals or something in that area... but who the hell knows. I do know i'm not going to do any of the things you have done on your list.

er0080: you pulling yours this weekend?

 

[er0080]

yeah looks like tomorrow night. I'd be real careful with that $400 motor; you might be right back to square one with not just one, but two motors! At the very least, make sure your getting a motor w/o a cracked head. As I said, ask to inspect underneath the valve cover. I cannot stress this enough. If it looks like they wiped the oil and crud from the top of the cylinder head, or they are hesitant about taking the cover off for you, tell him to take a hike or piss him off and offer him $100 or something like that. 0331 heads are present on all 2001 4 liters. If I were looking for a new motor I'd definitely go with something between 96-99. Having seen the quality of the cast of the 0331 head, and considering they did also change the block cast in 2000 as well, I don't think I spend any money on a motor of this year regardless of its condition.

 

[Creighton]

Did you pull your motor by chance er0080?

 

[Creighton]

Hooked up a mechanical gauge today. When my stock gauge would "plumit" to 0psi on the cluster the pressure was actually hovering right around 8-9psi. So for the time being i'm just gonna run 20w50 and see what that does.. my mechanic says he's leaning towards cam bearing maybe.

 

[Creighton]

Now its running 20w50 and some Lucas... drove it around for a bit... at FULL hot temp it did eventually get as low as 5psi on the mechanical gauge before switching to a thicker oil. Now at hot it doesnt go below 14psi... so i'm gonna toss a mechanical gauge in just to keep an eye on it while i'm on the beach and such and just run 20w50 until I start to notice anything funny, or until I get a huge urge to open the motor.

 

[er0080]

Creighton-

no, I havent got the motor out yet. I'm hoping to start on it this weekend, but we'll see. I'm just getting over a bad cold so I'm kind of weak at the moment. I will definetely post my results ASAP. By the way, are your lifters still noisy at idle with the heavier oil? What does your oil pressure get up to on the highway now? Just curious

Eric

 

[Creighton]

Creighton-

no, I havent got the motor out yet. I'm hoping to start on it this weekend, but we'll see. I'm just getting over a bad cold so I'm kind of weak at the moment. I will definetely post my results ASAP. By the way, are your lifters still noisy at idle with the heavier oil? What does your oil pressure get up to on the highway now? Just curious

Eric

ya, lifters are still alittle noisy... that airy thft thft thft sound.

Currently:

Cold - 50psi while driving and getting up to speed. Idle - 40psi
Warm - 40psi ish and 30 psi idle
Hot (about 30min of driving) - 28-30psi driving and 10-12 psi idle (after i sit and let it idle for a few minutes.

BUT those temps are on my stock gauge.. before when the guage read 0 it was actually at 5 psi... so i figure add 5psi to all those #'s.

 

[er0080]

ive decided to drive the motor till it blows up! I simply don't have the time right now to be messing with this since my backup 88 xj's head gasket is now blown. I'm not going to put any money or time into it, so Ill deal with my 2000 when its on its last legs!! I Will definitely post results when the time comes. I'm assuming this will be soon, considering I now have only 10 pounds of pressure at highway speeds with 20w50!!!!!

by the way creighton, I've noticed that the stock gauge/computer has a lower pressure sensor bound of ~5-7psi, below this, the needle will peg zero and check gauges light will illuminate no matter what the pressure is. I've found that with two separate mechanical gauges that my cluster gauge is accurate to about +/-2 pounds (above ~5-7psi, that is)


Eric

 

[KaHOnas]

Has anything more come of this thread? I've been having nearly identical problems for a while. I was considering replacing my sender and seeing if that'd work but from what I've read here it'd be pointless. DC will never fess up to their crappy 0331 heads, will they? So I'm just waiting for my engine to die, huh? This is my wife's daily driver. We have a child on the way and I can't be dropping thousands of dollars here to fix a problem that shouldn't have happened in the first place.

Anyone have any ideas or new information?

David
'00 XJ Sport 4.0 4x4 auto