Decemberist

I just finished removing my 2000 jeep xj 4.0 cylinder head, when I pulled it free quite a bit of coolant leaked out...is this normal when doing a head gasket?

5-90

I'm assuming you drained the coolant first? Yes, it's fairly normal to see coolant when pulling the head - I think it's happened in probably five of seven engines I've torn down over the years (the exceptions being engines I've had on a stand, and had turned over and up again to get to bottom-end stuff and the like.)

tjwalker

Let's go back a bit. Why did you have to remove the head? Are you absolutely SURE that the problem is just the head gasket??

You may already know this, but the factory 0331 head has a factory defect between cylinders 3-4, which make it very prone to cracking there.

For this head, a cracked head is way more common than a failed head gasket.

And when I remove a factory (not redesigned) 0331 head, it doesn't go back on that engine. Too risky. Put a redesigned (Clearwater Cylinder Head and Alabama Cylinder Head are good sources, or you can safely use a 2003 or newer 0331 head from a Wrangler or a Grand Cherokee.

Give us some more details and we might be able to help you more. I have had a lot of experience with the 0331 head problem.

J91gt83b

^Im keeping an eye on this thread cause of the guy above^.

Decemberist

TJ,

I thought it was the head gasket because I was loosing coolant, low oil press and misfiring on #3 cylinder. I did a leak down test, verified oil pressure and sent oil out and it came back positive for anti-freeze. However, when I pulled the cylinder head the gasket looked ok. It is the 0331 head, and am in the process of cleaning it up and having it NDI'd but if it is cracked I have a spare head out of a 97 xj 4.0 that should fit my 2000.

crystalion

I wouldn't even bother getting the head checked --Just replace what is an already known defective part and be done with it.

tjwalker

I'm guessing that this head is cracked. You have all of the symptoms including losing coolant, low oil pressure and cylinder 3 misfire.

I would never put this head back on your engine. Period. The head is a dog, and it is just too risky to reinstall. Should be used for nothing more than a boat anchor........

Let's just assume for a minute for the sake of argument (testing will tell the true story) that the head is cracked. A different head would take care of that, but would NOT resolve the low oil pressure you are seeing, which is generally caused by the antifreeze damaging the engine bearings. Coolant in the oil is a bad thing. So you have not only the head to consider, but the engine itself.

A lot of guys have ended up putting in a salvage yard engine in this case. With a cracked 0331 head, you can generally save the bearings, but only IF you resolve this very quickly. And once the oil pressure gets low, it usually is too late for the bearings.

Here is a link to required reading for anyone with a 2000-2001 4.0 XJ. It has the trials and tribulations of many 0331 head owners.

http://www.jeepsunlimited.com/forums...d.php?t=391831

Will all 0331 heads crack? Absolutely not. But this forum and the others that I frequent are full of threads from owners that have had this happen to them. An overheat of the engine virtually guarantees a cracked head.

Good luck!

crystalion

Anyone get /have /or buy an off the shelf rebuilt unit. Basically just keeping the old one for spare parts and doing an engine swap. I have a 2000 that has excellent oil pressure and no coolant loss YET ! Also I'm sitting at 90K which seems like a high % point on failure time.

Just would like to know how much $$$$$$ they are.

tjwalker

Clearwater Cylinder Head and Alabama Cylinder Head will sell you a redesigned (new) 0331 replacement head for around $500. Their warranties vary a little so do your homework, but they are both very reputable and trustworthy vendors.

Decemberist

I think that I am better off using the cylinder head from the 98, will the 98 head be a direct fit and will I have to change anything before I install in on the 2000 4.0 block?
I did think about the coolant damaging the bearings, (idle @12-28psi warm) but there is no rattling from the engine whatsoever and it still has plently of the 190hp it's rated at.

tjwalker

Jeep oil pressure spec is as follows:

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

If you are within those spec numbers, you have most likely caught this before a lot of damage has been done to the bearings.

That Jeeps Unlimited link I provided should discuss options and ramifications of using pre 2000 and also 2003 and newer Jeep heads.

When you get a different head on your engine, be sure to change the oil and filter FREQUENTLY for about 3-4 times to purge all traces of the coolant from the existing oil. One oil change simply won't do that for you.

halligan.evan@gmail.com

Anyone know if the 99 2.5 head has the same issue? About to replace the gasket on mine due to coolant leakage into the cylinder but am wondering if I should be replacing the head instead?

Jeep Driver

No, the 2.5 has no such history.

If you are concerned, have the head checked at a machine shop......better yet, have it reconditioned.

dave1123

ALSO, the 98 head will bolt onto the 2000, but the exhaust manifold will not fit properly, plus you don't have the 4 bosses for the coil pack. The 98 is a 0630 head.

I was lucky with my 0331 head because it cracked into a valve port and hadn't gotten to the point where it was leaking coolant into the oil. I had lots of steam out the tailpipe and it was dripping coolant as well. It's running fine 50K miles later.

halligan.evan@gmail.com

Thanks for the info, already have a shop lined up to check her out just tobe sure!