884x4

Sister bought a 01 XJ 4.0 4x4.
I knew of the 0331 head issue but she got an okay deal on it and it seemed to keep cool driving it.
Well long story short she was driving it and said it started knocking and lost power. I went to where she was and checked the oil for correct level and make sure there wasn’t any coolant in the oil. She said it never got hot so I tried to drive it to my house. Started knocking lost power and died. Pulled over and the engine was HOT. (Coolant gauge showed 210 but at that point I knew something was up)
got to the garage and wanted to see the condition of the coolant. Pulled lower hose and nada. About half a cup of brown coolant came out. I figure the guy knew it had a cracked head and drained all the coolant when he figured out the temp sensor still read 210 with hot air or he effed with the temp sender. Once it cooled off again and I had time to mess with it I turned over the engine right quick to check oil pressure, idled strong and oil pressure was 40psi and Im prettty sure it’s still got good rings with how well it ran other than a very slight bottom end knock. Well now i have a decision to make. Either replace the head and run the original block, put a Remanufactured 01 engine in it(which I don’t like due to them using factory 0331 heads rather than TUPY heads) put a Remanufactured 98 engine in it and change the exhaust manifolds and swap over the coil distribution packs or change the head and rebuild the bottom end myself.
Anyone know of a way to check condition of main bearings short of pulling them and doing a lot of measuring?
I hope I can get away with just a head from Clearwater or somewhere but figured I’d talk with y’all first.
thanks and sorry for the long post

lawsoncl

Have you looked and confirmed the head is cracked? Was the oil milky? How soon after purchase did this happen? If he drained the coolant, she probably wouldn't have made it through a test drive much less home. It's a hard lesson to learn, but when buying an 18-year old vehicle you really need someone with mechanical skills to look it over for obvious problems. Even then, you can have surprises. I bought a 93 ZJ and the water pump blew up 3-months after buying it - literally, it spit the bearing out the front in pieces. I found the pump and radiator were clogged up with bars leak from the PO.

884x4

Plenty of mechanical knowledge here man. Oil was not milky. Anyone who’s trying to dump a jeep with a cracked head would know to change the oil. Unless there was coolant and it all evaporated or it lost it all in the small amount of time she was driving it(about a week) and never told me it was leaking I really don’t think there was ever coolant in it. It was driven less than a couple miles for about a week until she tried to drive a longer distance and that’s when it acted up. I obviously could pressure test the cooling system or even just pull the head to see if it’s cracked but at that point I’m wasting time if I need to put a block in it as well. I could even compression test the cylinders but once again a waste of time if I’m gonna put a whole motor in it

GreaseMonkey17

Sounds like you already have all the answers to your own questions ...

884x4

I wish lol I guess what I was really wondering is how many of you would throw a head on it and pray and how many would replace it as a whole hoping the bottom end is still in decent shape?
With the good oil pressure I was hoping all the main bearings are still in good shape.
You may be right though, I have a gut feeling I should put an engine in it for her but I guess I was hoping otherwise and could get away with a head lol

dave1123

Drop the pan and check the bearings. If none are scored they are probably still okay. No sense in pulling the engine if the bearings are still good. Wheither the head is cracked or not, I'd put a Clearwater or later model "TUPY" head on it and call it good, AFTER inspecting the bearings. Depending on the mileage, you should consider a new oil pump while you have it apart.

That 01 runs on a completely different computer system than the 98 you're considering using. Changing it over could become a nightmare.

00t444e

The 98 engine will work fine, you just have to use the wiring harness, all the sensors, coil pack and accessories from your 01 model. However if the bottom end on your 01 engine is OK I would just put a hood head on it and be done.

Dave51

Like opening the radiator cap when you know you've got an 0331?

884x4

yeah I was gonna drop the pan and pull some caps this afternoon.
and if I used a 98 it would be just the block, head and intake/exhaust manifolds. Just more of a headache for me.
thanks man

Lol not arguing that. I pulled the stick and oil was clean so I wasn’t worried about it thinking coolant usually will be in oil rather than the other way around due to higher pressure in the cooling system. Didn’t really think the cooling system would be bone dry but sh*t happens and it wasn’t my jeep.

Dave51

Well IIWM I would consider

Perhaps the seller was really an honest person and there is an external leak somewhere. Not all 0331 heads crack. I don't know what the real percentage is, but I saw a straw poll once that called it 20%.

Of course, now that it overheated it might have cracked, but hey, you could be lucky.

Looking forward to what you find.

884x4

That’s true and could be a possibility, idk how hot the engine got, you could not touch the valve cover without getting burned, wish I had a IR gun on me when it happened.
But the strangest thing that the gauge always showed 210. The sensor was plugged in and temp gauge needle moved from cold to 210 so I assumed it was all well and working. Either the sensor reads very hot air at 210 or something else is wrong with the sensor. Which may make sense as I pulled codes yesterday and it was throwing a P0118 which is high voltage for temp sensor in the thermostat housing.
I’ll pull the oil pan and check condition of the main bearings and pull the head to visually inspect.

dave1123

IDK because I haven't experienced it, but I've been told there's a problem with the exhaust manifolds of the 2001 lining up with the 97 head because the ports are smaller on the 01. I've heard stories of mismatch the other way around where the steel header from an older engine hits the block and won't allow it to seal against the 0331 head. What I'm saying in effect is the 97 block will work as long at you use an 0331 pattern head in it and use all the 01 parts and accessories. My 2000 XJ uses the old block with the 0331 head and coil pack system on it from the factory. I have the old style oil filter adapter and a cam sensor instead of a distributor.

The 0331 head usually cracks between the #3 and #4 cylinder in the rocker area. If you take the oil filler cap off and shine a flashlight down the hole, the crack will be right under the oil filler cap between the 2 exhaust valves. The head on my 2000 WJ 4.0 cracked into the exhaust ports but didn't make it to the spring area. What I got was loads of steam out the exhaust and coolant dripping from the tailpipe. No coolant in the oil pan. I got lucky. These heads will almost certainly crack on a 260* overheat, but sometimes crack for no reason other than that they can! IBT they usually crack around 125K to 175K and not all crack, but they are like a ticking time bomb. The 0331 "TUPY" head was introduced during the 02 production run. It was cast by the TUPY foundry in Brazil using more nickel in the pour to make it more flexible.

Sorry the pic got loaded before the text. BTW, I'll bet the temp gauge was reading the steam temp, not the coolant temp because there WAS no coolant.

884x4

Yeah I’ve know about the issue with the head which is why I tried to get her to buy a pre 99 but the only ones she could find were 00 & 01.
i tried looking for the crack through the oil fill hole before she even bought it. I was under the impression you would see coolant coming through the head right there between 2&3 so I assumed it was okay not knowing the cooling system was dry.
That’s just wild to me that the gauge would read the steam temp right at 210 but is a good lesson learned and hopefully will help the next guy buying one if they ever read this thread(partially why i even posted due to not knowing that was even possible)

From what I understand Clearwater heads use the TUPY casting which is what I would want if I need to put a head on it.
Good tech info here guys I sure appreciate it

dave1123

It's possible that Clearwater has started using TUPY castings due to increased demand, but when I bought mine, it was a new American casting made by them. It also weighted 12 lbs more than the original head. The bill of lading said 90 lbs and the returned core weighed 78 lbs. The Fedex guy dropped it on my lawn 1/2 way to the porch! The return core went USPS Scrap Metal. They provided the prepaid shipping label. The original price for the Clearwater at that time was $455 but I think they are more now. From what I understand they are using 3rd party sellers. They are warrantied for 60 months against cracking and there's a melt tag on the back side of the head. If the tag is melted, it's your problem.

PatHenry

I had a 0331 head on my 00 TJ and that engine runs great today and never cracked on me.

Personally, I'd change the oil and flush the coolant before doing anything else, see where you're at and go from there if you're not 100% certain that the head is cracked. If you are, more than likely you're good to go with just a new clearwater head.
If you're going to pull the pan and check the bearings - go for it and then you'll know.

One thing to consider, you could pull the block from the 98 and put a clearwater head on it and you'd be good to go. The blocks are completely compatible per Cruiser's "Engine interchange" sticky post.