Hi, I am considering buying a 2001 xj with 130,000 miles. It was previously owned by the state so there aren’t very many records on the car fax. I was worried about it because I have heard bad things about the 2001 xj head gasket cracking. I know the 4.0 liter inline 6 is legendary, so if the head gasket was replaced with a new one, would it last for a long time after that? Or would the new one crack not after long as well? Feedback would be greatly appreciated, Thanks!

 

Note from DJ
It’s not the head gasket that goes bad; it’s the head itself that cracks!

 

Might crack in the same way a person might develop a terminal illness, no guarantees either way. If you like it buy it, don't worry about it & drive the **** out of it.

 

 

Get replacement head from Clearwater cylinder head in Florida. Not to pricey.
I would consider now rather than later to avoid possible damage.

 

A new cylinder head is only about $500 and any shade-tree home mechanic should be able to change it out in a full day of work. A professional shop should be able to do it even faster (you just remove the intake + exhaust manifolds, plus some other top-end bits, and pull the head off). Easy compared to many vehicles

Shop labor is always expensive but again, simple task so shouldn't be that bad. No more than $1500 including the head for a shop, and even that seems a bit high in price.

At 130k miles, I would just change the water pump, coolant, and thermostat for peace of mind. Other than that, all you can do is hope that it doesn't crack, but running it hot is one sure way to get the head to warp/crack

 

For the most part. That year also had some piston skirt issues and a TSB for a valve rotation problem, but the 0331 head crack is the thing that gives these years their bad reputation.

It's not exactly like getting a terminal illness. It's more like contracting a disease and dying because you ignore it. If the head cracks and you start getting coolant into the oil, the coolant will begin eating the bearings. If you identify it fairly quickly, it's a $250 to $600 repair to swap the head yourself, depending on what head you use to replace it. Then the engine is fairly reliable. But if you let it continue to eat the bearings, you end up having to rebuild or replace the long block instead.

The key here is to read up on the symptoms ahead of time so that you know what to look for and what to do if it happens. The ones people lose are from not taking action until it's too far gone to fix. Some people just go ahead and swap the head preemptively, so that they don't have to worry about it.

 

 

#1 most important thing to look for is rust, that will quickly become an issue that costs more to repair than the vehicle is worth. Also remove the radiator cap and have a look inside there should be coolant and it should be green if it resembles brown mud, pass...
If the cooling system has been neglected chances are the whole thing is trashed.

 

I bought a 2000 where someone had replaced the head. I didn't know it. They didn't torque the head bolts back down properly and years later it developed a leak. It overheated and that engine has been out of commission since.

If you do nothing else, get a torque bar and go around checking the torque specs (tightening to 110 in the correct pattern, 100 on the 11th bolt) to verify they didn't botch it. It's hard to torque that rear one in the very back with the stud on it unless you have the engine out, so they didn't torque that one properly. The torque specs were also very uneven. I don't even think they used the torque specs. I think they just tightened them by hand "pretty good", where they could. I have found all kinds of damage on this vehicle they did over the years. I think some high school kids with no know how must've owned it before.

It's always better to replace the 0331 for another head pre-emptively rather than after the fact. By the time there's enough heat built in the head to heat the sensor up when your coolant has been empty, you've done toasted the engine and the whole thing needs taken out and repaired or replaced. Don't dilly dally around with getting the head changed later if you can do it sooner.

If you don't have any plans on living in Ca I recommend you toss those infernal pre-cats just under the intake manifold. They produce an excessive amount of heat and aren't helping the engine live longer. Heat is bad, cats are the hottest part of a vehicle. They have no business being anywhere near the engine or the intake. It was amateur hour at Jeep when they engineered those, and I think they did it on purpose to increase wear and tear.

 

Legally, you can't remove the pre-cats. It does not matter what state you live in.

https://www.epa.gov/sites/production...hsysrepair.pdf

 

Yes, Jeep engineers have been known for years to do this. Then, years later when the vehicles with this deliberate flaw show up at dealers for service the engineer who deliberately designed an increased wear item gets 10% of the service bill as a bonus. It's a shame they couldn't get the private shops in on paying the bonus, then this would have been a perfectly executed evil plan.

Also, as stated above it is illegal to remove emission control items regardless of your state's individual emission requirements.

 

 

While I agree that it's especially bad for an XJ, considering that they already had relatively high underhood temperatures, it's very common in modern engine designs to close-couple the catalyst(s) for quicker light-off. It's more probable that's what they were going for. Take a look at most recent FWD designs for instance, and you'll find that the catalytic converter is usually as close to the exhaust ports as they can locate them, right next to the block just like the CA emissions XJs. Granted, the intake is usually on the opposite side of the block in those designs, but I doubt Chrysler gave that a second thought since they were trying to please CA in the final two production years of the the XJ.

 

Yep, you got that right. My FWD car has got a cat that butts up against the turbo. It probably has about 6" from the turbine wheel to the start of the cat mesh. It also has another one down under the car. Moar cats are better right? I know some Subis have 3 cats. There is an extra one between the headers and turbo. Got to love the smell of an over heated cat(s)! Or not...