2000+ head cracking

[falcon556]

Done some searching, it appears that 4.0 engines with a casting #0331 have the habit of cracking up between #3 and #4 exhast valves.
My question is, has anybody figured out exactly which years and models are affected? Did they ever fix it? When?
What is a direct drop in replacement for the defective heads?
These heads have the newer ignition system attachments and older heads will not work without modifications.

[jeepdude10000]

if u did more searching in this forum u would find the answer, it was answered about a month ago, if i come across it i will post the link.

[falcon556]

Originally Posted by jeepdude10000

if u did more searching in this forum u would find the answer, it was answered about a month ago, if i come across it i will post the link.

I found all kinds of information, none addresses my needs.
I need to know whether 0331 heads were ever fixed, if so, what year, VIN,
casting #, anything. If not, how can a cracked head be fixed with a drop in
fix, without using another defective 0331. After reading pages of info, I didn't find what I need.
Unless of course I missed it.

[UNCC_99XJ]

Depending on who you ask depends on whether the 0331's started in 99 or 00. I've got a 99 with the 0630.

If you're looking at doing a replacement I believe the 0630's will match up, as well as the casting on the pre 96's...as long as it's a H.O. I could be wrong however.

[falcon556]

Originally Posted by 99XJSPORT06

Depending on who you ask depends on whether the 0331's started in 99 or 00. I've got a 99 with the 0630.

If you're looking at doing a replacement I believe the 0630's will match up, as well as the casting on the pre 96's...as long as it's a H.O. I could be wrong however.

I have a 99 with a 0630 and 01 with the 0331. I think the 0331 came with the ignition rail in 2000.
I don't think that the 0630 can replace the 0331 because you need the attach points of the 0331 for the ignition rail.
This is why I am trying to find if it got fixed in later years or if there is another head from a 4.0 that will drop in.

[Fish'nCarz]

http://jeepsunlimited.com/forums/sho...d.php?t=721472

[falcon556]

Originally Posted by Fish'nCarz

http://jeepsunlimited.com/forums/sho...d.php?t=721472

That's great and if I have to I might go the same route.
OTOH if the problem has been fixed at some point, the solution is not to hang the ignition rail from the valve cover, it is to replace it with a head that will not crack.
His idea is great, I just can't imagining doing any serious 4X4 with my ignition
rail hanging over the spark plugs. That's why I'm asking questions here.
We can't call DC, they'll prolly deny everything.
Another reason that I need to know is that I may have to buy another XJ soon.
I will not even consider a 2000+ unless I know more about the head problem.

[x99j]

it does not effect all 0331 castings. the theory is their was a couple of bad runs unknown dates that were effected. the ones that do crack seem to only crack after significantly overheating. the posts i see don't seem to crack out of the blue. my build dat is 5/99 and i have an 0630 head with a distributor. they also continued to use the 0331 head on other models up till 03-04ish. if you look on e-bay or auto trader their are alot of 00-01's (0331's) with alot of miles on them. but i do not think you will get out of jeep what exact 0331 production dates are effected?

[falcon556]

Originally Posted by x99j

it does not effect all 0331 castings. the theory is their was a couple of bad runs unknown dates that were effected. the ones that do crack seem to only crack after significantly overheating. the posts i see don't seem to crack out of the blue. my build dat is 5/99 and i have an 0630 head with a distributor. they also continued to use the 0331 head on other models up till 03-04ish. if you look on e-bay or auto trader their are alot of 00-01's (0331's) with alot of miles on them. but i do not think you will get out of jeep what exact 0331 production dates are effected?

OK, the only way to play it safe will be to stay with 99- on the XJs.
I'll keep an eye on my WJ in case it cracks up and I'll keep checking here for more info. Somebody may come up with a way to modify a 0630 to fit later models.

[Fish'nCarz]

Originally Posted by x99j

it does not effect all 0331 castings. the theory is their was a couple of bad runs unknown dates that were effected. the ones that do crack seem to only crack after significantly overheating. the posts i see don't seem to crack out of the blue. my build dat is 5/99 and i have an 0630 head with a distributor. they also continued to use the 0331 head on other models up till 03-04ish. if you look on e-bay or auto trader their are alot of 00-01's (0331's) with alot of miles on them. but i do not think you will get out of jeep what exact 0331 production dates are effected?

I've looked into this alot, and writen to Jeep, as I had one crack on a 2001 xj. Jeep sez no recall, have a nice day.

I don't believe it was limited to "a couple of bad runs unknown dates that were effected." I think there is a defect that, while it may not be present in all #0331 castings, is intermittent enough that there is no way to tell if you have a bad one until it fails. I don't know if it was casting process, metal used, the molds themselves (by the way, there is not just one 0331 mold making all the heads from July '99 on), or the day of the week the casting was poured, but there is a problem over several years, and it only shows up after a good number of miles. Heat certainly may be an issue, almost certainly is. It seems very fishy that the same engines are prone to throwing the "misfire on cylinder #3" error code on hot restarts, doesn't it?

Mine puked at 49,000. Most seem to go at around 60,000 or so. One of these days we'll know what DC knows, but until then it is certainly a caveat emptor issue.

[falcon556]

Originally Posted by Fish'nCarz

I've looked into this alot, and writen to Jeep, as I had one crack on a 2001 xj. Jeep sez no recall, have a nice day.

I don't believe it was limited to "a couple of bad runs unknown dates that were effected." I think there is a defect that, while it may not be present in all #0331 castings, is intermittent enough that there is no way to tell if you have a bad one until it fails. I don't know if it was casting process, metal used, the molds themselves (by the way, there is not just one 0331 mold making all the heads from July '99 on), or the day of the week the casting was poured, but there is a problem over several years, and it only shows up after a good number of miles. Heat certainly may be an issue, almost certainly is. It seems very fishy that the same engines are prone to throwing the "misfire on cylinder #3" error code on hot restarts, doesn't it?

Mine puked at 49,000. Most seem to go at around 60,000 or so. One of these days we'll know what DC knows, but until then it is certainly a caveat emptor issue.

Chrysler must have figured out at some point that there was a problem and must have fixed it. I bet that the heads made after a certain year and model are OK.
At this point I see two problems.
First having a head that can go and take along the entire engine unless it is discovered early enough.
Second, if it is discovered early enough, there is no fix other than installing another potentially defective head. Can't even consider replacing it as a preventative measure.
Both problems are serious.
One of the things I like in XJs is that they are predictably durable.
You know where you stand. Unless you have a 0331 head that is.

[jimbow912]

Originally Posted by falcon556

I have a 99 with a 0630 and 01 with the 0331. I think the 0331 came with the ignition rail in 2000.
I don't think that the 0630 can replace the 0331 because you need the attach points of the 0331 for the ignition rail.
This is why I am trying to find if it got fixed in later years or if there is another head from a 4.0 that will drop in.

u can get ridof the ignition rail and put a destribeatr in that warks I have see it done

[Dave4.0]

I read on here about someone who made some sort of bracket to secure the ignition coil to a 0630 head.

It's tough to say if and when the 0331 head problem was fixed. Chrysler won't admit that it's a problem, and alot the newer model 4.0's are just starting to get into the head cracking mileage range.

For the record, the head on my 2000 cracked without ever being overheated, or abused. It literally just went. The coolant was flushed about a year before it happened and my Jeep was in excellent mechanical shape with all maintenance up to date. That's probably what pisses me off the most. I took good care of it and it let me down.

Knowing what I know now, I'd never buy another 4.0 Jeep that was made after 1999. In fact, mine will be going up for sale once I move into my new house in September.

Wow, I sound like a whiny bitch.

[avnsteve]

you should just give me that POS right now, hell I feel so bad for you and that crappy 2000 model xj, I'll give you my 88 in exchange...

[rebeltruce]

I just bought my 2000 XJ, I wish I 'd have seen this forum prior to buying it! I may have just fixed my 93 Grand Cherokee and put another 200K on her........I'm about to turn 79K on the XJ, so I guess I'm in the danger zone.

Right now she seems to be running strong...stays right at 210', I do miss my V8 though!