I'm thinking an experienced pro is saying, what has gone on with that engine, how long was it run with a gasket leak, likely bearings might be trashed, maybe got cooked, and rings have lost tension etc
ie..not worth professional risk of just doing head, given all round low compression

hard choice for the OP, I would ask the mechanic what he would do if it was his, out of wrecker engine, or "crate" motor..even a rebuild of original motor

 

If it was overheated badly it could collapse the rings, which can give you zero compression. That means new rings at the very least, and in my opinion, if you just do the rings after having coolant in the oil, you are just being penny wise and pound foolish. You'll be pulling that engine again in the not-too-distant future, and doing it right. Might as well get it right the first time.

 

If the body, interior, and all else is in good shape, invest in a new motor and enjoy your Jeep for the next 20 years with proper care and maintenance.

 

I did ask that He said he would just throw in a good used motor and call it a day. My thought is if I'm going to go through the effort I might as well get one with a warranty. The company he suggested has a 5-year unlimited mile warranty. The Mechanic put one of there motors in his office manager's car and she was happy with it. The HQ for the engine company is like 30 miles from here so I like the idea of supporting local companies. Plus if I have any real issues I have no problem driving there and saying WTF
I did some searches on all 3 of the companies he gave me quotes on and the reviews on all of them were 50/50 on here. But that's pretty much any company you search someone will have something negative to say about everything.

 

Yeah, the rest is damn near spotless. I can't find any rust on it. The interior is nice. It did sit for over a year before I bought it so I think a mouse was living in the glove box but other than that its in really good shape.

I think that's what ill do. I want to order a few other things while it's out like Brown Dog motor mounts and maybe upgrade the radiator.

Basically with the new motor and a few odds and ends I'll still be at or under 4000 total for the Jeep.

 

If.

Anyway testing is free, and I'm really testing the mechanic.

 

It looks like you've decided to go a remanufactured engine route. Good choice if you can afford it and you plan on keeping the Jeep.

Out of curiosity, what did you pay for the Jeep?

Things to consider;
- will the remanufactured engine have the TUPY head? Find out what it takes to get a TUPY head in there.
- purchasing a high flow water pump. I used a HESCO. www.hesco.us
- purchasing a high flow thermostat housing. Again, I used a HESCO.
- purchasing a thermostat with the steam hole. If the thermostat fails in the closed mode, at least there will be a little bit of coolant circulating throughout the system.
- external transmission cooler. I also installed a transmission gauge down by the 4x4 shifter.
- silicone radiator hoses & heater hoses. These have a longer life expectancy.
- it sounds like you are already upgrading the radiator. Excellent choice.
- A quality & TESTED radiator cap.
- distilled water mixed with antifreeze or just buy the premixed antifreeze.
- serpentine belt / accessory drive belt.
- 6 new sparkplugs.
- maybe consider the 4 hole fuel injector upgrade.

Everything I mentioned, should help your Jeep run slightly cooler. My Jeep would run on just the plus side of 210*F, now it's running just on the minus side of 210*F. If I had to guess, I'd guess it's running 5*F cooler, which is 5 degrees further from overheating. I have the 0331 in my 2001 XJ.

Ask the technician what will be used from your old engine & put on the new engine. Ask about the Harmonic Balancer. Anything he is pulling off, ask if it's a wear and tear part. If so, consider replacing it. I wouldn't consider the oil pan a wear and tear part, but I'm guessing it will be switched out. Same for the valve cover, most likely it's getting reused. Ask how the flywheel / flex plate looks. Since the engine is out, ask about the front pump seal on the transmission. If it's been sitting for as long as you say, it might not be a bad idea to think about having all the fluids changed out. Differential fluid, transfer case fluids, power steering fluid, brake fluid, blinker fluid, etc...

I'm not sure if this next recommendation is snake oil or what, but ask if the cataltic converters can be soaked in a solvent to clean them out & extend their life. I have no experience with this cleaner for cataltic converters.

The only thing I would recommend to NOT REPLACE would be the downstream oxygen sensors that monitor the cataltic converters. I replaced mine, just because.... & within 20 miles of replacing the downstream oxygen sensors just because.... I now had a check engine light for low cataltic converter efficiency. $500 later, by replacing the cataltic converters, the light was now off.

In my profile is a link to my Jeep build that mentions everything I've done. Feel free to read it and get afew ideas. Especially with the parts I mentioned. You might be able to get a little discount in labor, because it doesn't have to come off the old engine and the money you are saving can be used towards the purchase price of new parts to install. Most likely, if they use an old moving part off your engine & put it on the new engine, that old used part will not have a warranty.

Hopefully some other members will chime in about some stuff I might have missed, or give their .02 cents about stuff I mentioned.

 

I just went thru replacing the engine in my 2000 WJ. (4.0L) I made several calls to rebuilders trying to find out about that 0331 head. The single answer I seemed to be getting was if the engine came in with a 0331 head and it checked out not to be cracked, it went out with that head on it. They also wanted my block number to match the replacement engine, so I couldn't request getting a newer engine that had the "TUPY" head on it. What I did was buy a shortblock (without the head) and had my Clearwater head reconditioned. After everything was said and done, it cost me the same as a complete engine, including labor of installation and reconditioning my head. HOWEVER, I now have an engine I can rely on! I was a little concerned because it had a low grade misfire at idle on cylinder #3 but that disappeared as the rings seated. Compression is good across the board now. This engine was from Maabco in Tyler, TX. When I bought my Clearwater head from Odessa Cylinder Heads in Clearwater FL in 2015, it cost me $455 complete with shipping both ways included. Because of demand, they are now selling them thru second party distributors and the price is somewhere near $525. You would have to call them to see if you could get one direct. I got mine in 3 days because they had a warehouse here in NY. It came with new valves, springs, and seals, ready to bolt on.

About the converters, my converters were very dirty from running with burning oil after 250K miles and I used Cata-clean to clean them out. They passed inspection with the new engine and they now have 253K miles on them, OE factory originals. I guess they weren't made in China!

 

$800 bucks
Thanks Ill consider a lot of these issues as we go forward Im meeting the mechanic again on Monday to talk about some other things I want to replace that dont come with the new engine.

 

The Head thing is a question I asked. Jasper said there was no problem with the head it was a head gasket issue and they use upgraded gaskets and have no issues. He also said these heads are now 20 years old the ones that are still good will prob always be good and the small% that failed should be almost all the way phased out by now since they dont reuse the crack heads. He said even the bad casting 0331s only had about a 25% failure rate and most people never had a problem with them.
Powertrain Products sent me a youtube video where they talked about the bad 0331 heads in the 4.0s and they said they dont use the faulty 0331 heads in their engines but they dont say what they do use so I sent them an email asking for more info. Interestingly they also said these engines are 20 years old now and most of the bad heads are gone by now. So I wonder if that's some industry talking point.
The 3rd company I cant remember the name, the guy on the phone said he had no idea and would find out.

But yes I may ask them to order the block from somewhere and the head separate from Odessa

 

The Odessa head is a new casting with more metal in the critical areas whereas the "TUPY" head is a new casting made for Chrysler from the Tupy Foundry in Brazil in which they put more manganese in the metal to make it more flexible. IDK if the tupy head from Chrysler comes with valves and seals, but I doubt it. You could probably get one from a junkyard and recondition it. About $50 for the head and $200 to recondition it. Some yards don't allow you to break down a good engine but some don't care.

 

It depends a lot on how available and inexpensive used engines are, and the labor cost of installation.

Over here, crate rebuild engines are too expensive, so used from a wreck is the only way apart from a rebuild, still very expensive

How much is a used engine in your area ?

I obtained a running used engine from a '96, for my '96ers with 170k miles for $300..did have to pull it myself, with the seller helping..I also obtained the AW4, NP242

wrecking yards typically want $600-750

 

There are a few used 4.0s on craigslist or facebook for 2 or 300. I just dont trust a used engine if im going to spend the time and money id rather put one in with a warranty. Right now the motor and install kit is 2150 and labor for the install is 645 So then im adding a few hundred for other odds and ends if It stays under 3200 then ive got the rust free xj in great condition with a new motor and 5 year warranty for 4000 bucks.

 

Have had 2 xjs since 2001 now driving 2000 X2 on motor with warranty also have them flush cooling system and maintain it. 67 yrs. old. and still LOVE driving mine. Good luck and enjoy enjoy!!!
has 225k plus miles on it

 

So I went back by the shop last night and had a friend who rebuilds old John Deeres run a compression test for me the results were 100, 105, 90, 100, 120, 100. So it was slightly different then the numbers the shop gave me but not by much.

But honestly I have no idea what any of this means. I know zero about engines. I can change the oil and anything that bolts on like starters and alternators but that's the end of my skill set at the moment