Low oil pressure on our 2000 XJ

[Creighton]

I just had the exact same thing on my 2000 XJ w/ 94k miles. Oil pump was bad.

 

[DenLip]

You guys are scaring me! My 2000 w/62k was "supposed to be a youngster" among XJ's... and now we're starting to see problems with them that the earlier ones never had!!

I'll keep my fingers (and toes) crossed...

 

[ayers05]

An update...

First a re-cap of my symptoms:
Engine began to regularly overheat "CHECK GAUGES" light.
Frequently low/engine would drink coolant. Would need to fill to the "FULL" line every 2 months.
Oil pressure than began dropping to where it would idle under 10psi and then to 0psi and would only come up to 30psi at best while accelerating. "CHECK GAUGES".
Engine began to run roughly while gently accelerating like it was continually misfiring.
Changed filter and oil to a heavier weight. Did not fix and I observed an excessive amount of condensation residue on the oil filler cap.

-SINCE LAST POST-
Changed out the spark plugs and noticed charred residue on the 5th plug like a detonation/fuel rich problem. Also did a cylinder compression pressure test and all dry pressures were 135 - 155 x100 kPa (did not block the throttle body open by advisement of the shop local...should have).
When engine runs there is a slight metallic ticking audible around the 5th cylinder that sounds with the rpm. Thought to be an easy rocker arm problem.
Did the "dollar bill test" on my muffler as the exhaust sounds burdened. The bill would blow under the force of the exhaust and then suck in to the pipe and then immediately blow out again (puff, puff, suck, puff, puff, puff, suck, puff). Possible CAT problem?
Pulled the cylinder head cover and all intake/exhaust springs and arms look good. Did observe metallic filings at the base of the springs and got a better look at the "coolant green" I mentioned earlier. There appears to be a crack or a welding defect in the cylinder head between the 3rd and 4th set of springs (which is the same view I had when removing the oil filler cap) but nowhere else.

I finally succumbed and brought the Jeep to the dealer where I bought it and luckily for me I bought a 3 year engine warranty 2 years ago. The only thing is I would always do my own oil changes and did not know to keep my receipts from the purchase of that oil to aid in the warranty process. Does anyone know if that voids my contract? I have no receipts and no record other than every 6 months I would change the oil.

Any guidance appreciated. Was 2000 just not a good year or am I a bad XJ owner?

(On the plus side I am enjoying learning about my Jeep through this site and this whole ordeal).

 

[DenLip]

I finally succumbed and brought the Jeep to the dealer where I bought it and luckily for me I bought a 3 year engine warranty 2 years ago. The only thing is I would always do my own oil changes and did not know to keep my receipts from the purchase of that oil to aid in the warranty process. Does anyone know if that voids my contract? I have no receipts and no record other than every 6 months I would change the oil.

Any guidance appreciated. Was 2000 just not a good year or am I a bad XJ owner?

(On the plus side I am enjoying learning about my Jeep through this site and this whole ordeal).

While aftermarket warranties sometimes have a habit of being "hard to pin down"... the fact that you are taking it to the selling dealer is probably going to be helpful in that department. The way most warranties are written (and this MAY be the law) is that they cannot point their finger at poor maintenance unless that poor maintenance was the CAUSE of the problem. Simply "not having paperwork" is not enough. They need to PROVE, for example, that the oil had not been changed, and that it likely caused the problem.

Your history of overheating may work against you... or it may not. They could argue that "you overheated it several times (thru lack of due diligence in checking the coolant level), and therefore the head cracked".

In practice, I have nothing to compare with personally. But I DO know that my sister got a new cylinder head (paid by an aftermarket warranty) on a K-car when it blew a head gasket and overheated...

Den

 

[Dr. Dyno]

There appears to be a crack or a welding defect in the cylinder head between the 3rd and 4th set of springs (which is the same view I had when removing the oil filler cap) but nowhere else.

Unfortunately it looks like my diagnosis was correct. Right in between the no.3 and no.4 cylinders is where the 0331 heads commonly crack and yours appears to have done the same. Replace it with a '96-'98 era 0630 head. It has the same port dimensions as the '91-'95 7120 head so it'll outperform the 0331 head, and it's also much less crack-prone.
I think it's high time DC carried out a recall on all 4.0's with the 0331 head and replaced them with heads that don't crack so easily.

 

[bustednutz]

What years were the 0331 heads used?

 

[Dr. Dyno]

They were used in the 4.0 WJ (all years), '00-'01 XJ, and '00-'05 TJ.
'99 was a crossover year so some '99 XJ/TJ models may also have the 0331 head.

 

[jeep-noob]

where do you find the "0331" on the head?

 

[UNCC_99XJ]

where do you find the "0331" on the head?

Look on the drivers side of the engine (if you're standing infront of the jeep, looking towards the windshield, it will be on your right). About halfway down the engine, around the #3 and #4 cylinders, you'll see the casting number on the head. You'll probably need a flashlight to see it better.

 

[jeep-noob]

Look on the drivers side of the engine (if you're standing infront of the jeep, looking towards the windshield, it will be on your right). About halfway down the engine, around the #3 and #4 cylinders, you'll see the casting number on the head. You'll probably need a flashlight to see it better.

thank you

 

[LRRH]

my head cracked in the normal spot around 90,000 miles (2000 XJ, owned since new). My girlfriend then overheated it enough that I had to do a full rebuild. Bummer, but my oil pressure is great now.

 

[Johann]

Replace it with a '96-'98 era 0630 head. It has the same port dimensions as the '91-'95 7120 head so it'll outperform the 0331 head, and it's also much less crack-prone.

Hey guys,

Just found this on search and had a follow up question. My mom just called me with the same tale of woe. Has the 2000 WJ at the dealer right now with a cracked head diagnosis.

What is involved in the head swap to the '91-'95 7120 head? Is it just the head or are there other bits that are involved like fuel system, manifolds, etc...? She is looking to have it rebuilt by the dealer to the tune of $2000 :tears: and I want her to get the most from her investment.

Since I suggested the Jeep in the first place and am too far away to fix it myself I feel of responsible to give her council.

Thanks for the help

John

 

[donovanb62]

I just wanted to chime in with a similar story and add to the thread. As I am not much to work on cars myself, but am here to learn in hopes of someday actually doing the work myself, this story may be a little stupid to some of you, because I had the dealer do all the work. Anyway, here's my story (sad but true, 2000 XJ, bought cheap from a local rebuilder with an r-title, my first mistake 3 years ago):

I overheated with 63K on the odometer on the highway. I pulled over and saw my overflow tank was literally overflowing with creamy, bubbly coolant. I drove it to the first exit (about a mile) and dropped it at a Bob Evans parking lot and had my wife come pick me up. I came back that night with 2 gallons of premix and saw the nastiest grime buildup all over (inside and outside) of the overflow tank. I cleaned it up and added some fresh coolant and started it up. It overheated as soon as I hit the highway. I pulled off again and this time had it towed to a dealer. The dealer called me the next day and said they couldn't find anything wrong except a dirty radiator. So they flushed it and replaced the thermostat and rad cap. Cost: $120

About 3 weeks and 1K later, I overheated again. This time I pulled off and let it cool, added some coolant I had with me, and it came down. So I drove it to the dealer. Verdict: they can't find anything wrong. They said they pressure tested and it held pressure. They said they ran compression tests and everything was fine. They told me to keep driving it and see if it happens again, then they'll be able to figure it out.

About 3 weeks and 1K later, I overheat again. Repeat exact same as above, pressure tests and compression tests again and eveything looks good, except this time they replace the thermostat and radiator cap again, saying that maybe one or both were faulty. I tell them to do whatever they have to do to fix it. I said I have no idea why this happening (I didn't) and I don't care what the cost is. They said they checked all hoses, pump, and they had no answer. I drove it home and everything was fine.

The next day I am on my way to work. I start to overheat. I start to hear a faint knocking. Very slight but definitely some sort of noise. The heat goes up, but not too bad, so I keep going and I'm keeping an eye on it. Another mile or so and all of the sudden, the thing overheats, my engine light comes on, and it feels I suddenly went from a 6 cylinder to a 2 cylinder. So I pull off and swear at the top of my lungs for 10 minutes. This is obviously a problem those idiots at the dealership should have been figuring out and saving me from, I think. This is obviously very bad and if they would have figured it out the first three I took it in, I wouldn't be in this situation, I say to myself. They will pay to fix it because it's on their shoulders, I think, so at least that won't be a problem. I called the tow truck and had it taken to the dealer.

Next day I call the dealer and tell him what happened. He's very sorry, he says, and will get right on it. His "get right on it" apparently means just whenever he damn well pleases, because I go the rest of the day without hearing back and call him back myself the next morning. "You have some major problems," is his way of putting it to me softly. As he goes through it, it is a real laundry list. Since this happened and I came to these forums to read about it, I see how this has happened to others (including those much more mechanically inclined than myself, which makes me feel slightly better). Here's the rundown:

Leaky exhaust valve (#3)
Cracked head
Bad seat
Shorted out coil pack
Damaged spark plugs

I argued with them everytime we talked until the day I drove it out of their shop about who should pay for it. I said they should cover the entire cost. They said no. I tried to say they should pay at least for the new head (a friend told me that the only way it cracked was repeated overheating), but they said that it could have been there for awhile. In the end, they made me pay for everything. They said that unless I could prove that the overheating caused any of these problems (which I can't, how could I?), that I would have paid the exact same cost the first time I went in, if they could have found the problem. Unfortunately for me, they said, it's just something that is hard to figure out, but there's no way of telling which happened first and what caused what. They said more than likely that I had all these problems the first time I overheated and they were sorry for not figuring it out sooner, but there's nothing they could do. I argued and cussed them out and made a huge scene at the dealership. They didn't budge. I thought I must be terrible at explaining my point or they were just a-holes. I still think they are a-holes, but it doesn't matter. I had to pay a total cost: $1,840

I guess I kind of wrote this like a story, but it was easy to write once I got going...this is God's honest truth. I probably look like an idiot to most people here reading this, but like I said at the beginning, I don't really do much work myself, but am learning and reading these posts to hopefully get to that point. Reading these forums and photocoping the pages from the service manual at the library helped me learn how to change my oil and replace my spark plugs. In an effort to try and get over this and not stay angry for so long, I keep telling myself that this was just a big learning experience.

Looking back, I also noticed a drop in oil pressure about the time I started overheating. I never said anything about it to the dealer, and didn't really think twice about it, because honestly at the time I wasn't sure if I was right in thinking I was down oil pressure or if maybe it flucuated before and I never paid attention. Looking back, I could really kick myself for being that stupid (chalk it up to inexperience). Paying attention to that probably would have helped. I did check the oil in between my overheats and I never saw a lighter color or water in the oil, to my knowledge and ability, that is. At least I've learned what a head, head gasket, valves, coil packs, and what coolant does in an engine. I really never knew much about this before. Thanks for reading if anyone bothered to read this far and sorry it was so long. Writing this made me feel better, I just wish I could get that $1800 back somehow.

 

[jeep-noob]

eh, geez man, sorry to hear all that (yes i read the whole thing). You should have a good rig now, and a lot of knowledge.

I have the 0331 head, we'll see how she fares

 

[Dr. Dyno]

They said that unless I could prove that the overheating caused any of these problems (which I can't, how could I?), that I would have paid the exact same cost the first time I went in, if they could have found the problem. Unfortunately for me, they said, it's just something that is hard to figure out, but there's no way of telling which happened first and what caused what. They said more than likely that I had all these problems the first time I overheated and they were sorry for not figuring it out sooner.

Unfortunately for you they're probably at least partly right. The head was probably cracked from the outset and everything else followed. I'm sorry it turned out to be such an expensive repair bill but if the stealership really did pressure test the cooling system repeatedly and it was OK, they would have had no reason to suspect a cracked head. I can only conclude that the pressure test isn't foolproof.
All of the cases of cracked 0331 head castings that I've heard of have occurred only in year 2000 models. It would seem that a bad batch of castings came out that year. The 2001+ heads seem to be OK so those who own a newer model can rest easy.
Anyone with a 2000 model TJ, XJ, or WJ should watch out for the telltale early signs of a cracked head i.e. unexplained coolant loss, overheating. If you wait until you have an oil pressure drop or knocking from the engine, you may be looking at a total engine rebuild.
I think there's been enough cases to justify anyone who owns a 2000 4.0 Jeep to form a class action suit and force DC to recall these vehicles to have the heads replaced.

 

[jeep-noob]

Unfortunately for you they're probably at least partly right. The head was probably cracked from the outset and everything else followed. I'm sorry it turned out to be such an expensive repair bill but if the stealership really did pressure test the cooling system repeatedly and it was OK, they would have had no reason to suspect a cracked head. I can only conclude that the pressure test isn't foolproof.
All of the cases of cracked 0331 head castings that I've heard of have occurred only in year 2000 models. It would seem that a bad batch of castings came out that year. The 2001+ heads seem to be OK so those who own a newer model can rest easy.
Anyone with a 2000 model TJ, XJ, or WJ should watch out for the telltale early signs of a cracked head i.e. unexplained coolant loss, overheating. If you wait until you have an oil pressure drop or knocking from the engine, you may be looking at a total engine rebuild.
I think there's been enough cases to justify anyone who owns a 2000 4.0 Jeep to form a class action suit and force DC to recall these vehicles to have the heads replaced.

what percent of these heads fail, I mean i have one and just looked at it, no problem at 85k miles

 

[92DripCherokee]

I get uneasy reading these 2000 4.0 horror stories.

Last year I bought my wife a 2000 Classic with 58k, its about to roll over to 60k. I've got solid oil pressure, and its valve train is free of sludge or haze. It runs at 210F exactly. I bought a 18 month extended warranty on it, so what do I need to do? Crack it immediately for the coverage? Am I doomed? If I've got one of the 0331 heads, gulp.

I did my homework on the 2000 model year, there were no major recalls besides a heat shield. I thought I had a creampuff.

Are we looking at another defect on the scale of the infamous tubular exhaust manifold?

 

[DenLip]

I did my homework on the 2000 model year, there were no major recalls besides a heat shield. I thought I had a creampuff.

Are we looking at another defect on the scale of the infamous tubular exhaust manifold?

Let's get it straight. I have a '00 that I bought new. What that "recall" did... was add a reflectorized heat shield on top of the intake manifold. The alleged purpose was to "prevent debris from building up, and potentially causing a fire".

In 30k before the recall, I had not developed any debris.

In the 35k since, I haven't either... but it would be hard to see/remove it if I did!!

IMHO a useless recall. Potentially more hazardous than doing without.

IMHO, YMMV.

I'm hoping my head doesn't crack. That sounds like a painful thing!

Den

 

[Dr. Dyno]

what percent of these heads fail, I mean i have one and just looked at it, no problem at 85k miles

It's impossible to say what % of the 2000 heads crack but it does look like a batch of them have been cracking. The problem is that there's no way of predicting which ones are likely to crack. The only thing I can suggest is to monitor the coolant level closely and if there's any unexplained loss, to be aware that this could be an early sign of a cracked head.
All the heads seem to crack in the same place (between the no.3 and 4 exhaust valve springs) but the crack may be too thin to see with the naked eye, so the only telltale sign is discoloration from coolant stains in the place that I mentioned and you can see it when you remove the oil filler cap.
The crack usually occurs from overheating but not always. If you let the coolant level drop too low, there won't be enough coolant to cool the head and that makes things worse. Early detection of the crack and replacement of the head (don't bother getting it welded 'cause it'll crack again) will prevent other damage to the engine.

 

[jeep-noob]

It's impossible to say what % of the 2000 heads crack but it does look like a batch of them have been cracking. The problem is that there's no way of predicting which ones are likely to crack. The only thing I can suggest is to monitor the coolant level closely and if there's any unexplained loss, to be aware that this could be an early sign of a cracked head.
All the heads seem to crack in the same place (between the no.3 and 4 exhaust valve springs) but the crack may be too thin to see with the naked eye, so the only telltale sign is discoloration from coolant stains in the place that I mentioned and you can see it when you remove the oil filler cap.
The crack usually occurs from overheating but not always. If you let the coolant level drop too low, there won't be enough coolant to cool the head and that makes things worse. Early detection of the crack and replacement of the head (don't bother getting it welded 'cause it'll crack again) will prevent other damage to the engine.

Thanks, I did overheat in a steep hill, 100+ degree day with A/C on, but I chalked that up to the circumstances i put the jeep in, and reading other threads talking about inadequate cooling inherent to XJ design. I just did a valve cover gasket replacement, and carefully studied the suspected area of the head, but saw nothing, i dont loose coolant either.