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Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go hereXJ (84-01)
All OEM related XJ specific tech. Examples, no start, general maintenance or anything that's stock.
2000 XJ 4.0 auto 210K miles and I am the original owner.
Awhile back I noticed my XJ was still losing coolant after replacing the heater core with no signs of a leak. Then I noticed the milky oil on the filler cap. This lead me to believe I had the common cracked head. The Jeep has been parked since March of 2018 but started weekly or so and only moved in and out of the garage when needed.
About 6 months ago I did a compression test and all cylinders where in spec. Oil was clean, coolant was clean. The plug electrodes do have a green hue.
Earlier this week I pulled the valve cover and found a milky oily mess but no visible cracks. Also could not find 0331 on the head. What is cast in the head is “99” and “NH2”
Now this time when I pulled the dipstick it looked like chocolate milk. Drained the oil, pulled the filter and left the plug out for 2 days. This drain pan was filled considerably more than usual and it was a completely brown. Radiator was full.
It’s my winter project to get this back on the road, what’s my next step? Thanks. (not sure if I can link google images)
Man that looks nasty....I would pull the head and replace with a tuppy head. How long have you been driving like this? I would also go ahead and drop the oil pan and plastigage the bearing clearance and "hope" the cam bearing are OK / or say hell with it and do a total rebuild...
Year: 1998 Classic (I'll get it running soon....) and 02 Grand
Model: Cherokee (XJ)
Engine: 4.0
It might be the head gasket, not the head. You won't know until you pull it. Either way, that head has to come off.
Here's the good news - you may already have trashed your bearings.
If it's the head gasket, I'd replace it, put in fresh oil, and see what kind of oil pressure you have. Not really expensive if you DIY. If you have good pressure, great, off you go.
If not, well, time for new bearings at least.
If it's the head, you'll need to decide if you want to roll that dice. Heads are not cheap.
If it's a cracked head leaking that bad, I'd bet the crack would be visible between #3 and #4. Probably even get it to weep coolant if you hooked up a radiator pressure tester. I wouldn't trust that head enough to put it back on even if you found an obvious head gasket problem and it wasn't cracked.
(ah, tech beat me to it. I was just looking at that picture too.)
Year: 1998 Classic (I'll get it running soon....) and 02 Grand
Model: Cherokee (XJ)
Engine: 4.0
Originally Posted by lawsoncl
If it's a cracked head leaking that bad, I'd bet the crack would be visible between #3 and #4. Probably even get it to weep coolant if you hooked up a radiator pressure tester.
That would be much better than running that engine again to test it. Since coolant has been mixed in with the oil, every single time that engine rotates it takes you closer to needing a complete rebuild. I would not fire it up again at all.
Do you have a distributor or a coil rail...Only heads drilled for coil rail is the 0331...do you have a 2 piece exhaust manifold with 2, O2 sensors up high and 2 right below it a foot or so below 2 large bulges...if so then 0331......does your exhaust manifold end at oil pan top level or does it go all the way to bottom of oil pan...then 0331. Could be head OR just a gasket...you can get a decent totally rebuilt head on EBAY for under 400 bucks...its a pain in the *** to remove the head...Either way you need at least a gasket...for 400 bucks its NOT worth replacing the head when you do the gasket..Drain the oil, and replace with new filter too..use your usual oil weight...run until your hot..If IDLE press is above 20 psi you have not eaten your bearings...if 15 or below then bearings shot...needs total rebuild Its pouring rain up here in NY or I would open the hood and see how mine is marked...If your lucky you have a pre 0331 head...
It is coil on plug ignition. The amount of water in the oil seems odd as it looked good six months ago. Unless the issue could be from or escalate by not getting up to operating temp for so long. All though I have a 2.5 YJ that's hardly moved in 10 years with no issue.
I am on the search for a running 4.0 with a tupy head to swap out, then take my time rebuilding the original motor.
Last edited by cbwymore; Dec 10, 2019 at 10:13 AM.
It is coil on plug ignition. The amount of water in the oil seems odd as it looked good six months ago. Unless the issue could be from or escalate by not getting up to operating temp for so long. All though I have a 2.5 YJ that's hardly moved in 10 years with no issue.
I am on the search for a running 4.0 with a tupy head to swap out, then take my time rebuilding the original motor.
Well new they aren't that expensive... just my 2 cents....but if you're going to go through the effort to replace it, why risk someone else's problem. You never know how it was run, maintained, or even been overheated by another cooling issue on the donor jeep.
Markings on 0331 head. This is a "TUPY" head, but notice the 0331 in the top corner? Yours is under the heat shield. You can get a new "Clearwater" head complete with valves and springs for around $500. You can cruise the junkyards and find an 02 with a "TUPY" head for about $50 and spend $200 getting it refurbished.
Last edited by dave1123; Dec 21, 2019 at 07:10 PM.
Water in oil? Cracked Head?
