Is this the cylinder head that cracks? - JeepForum.com
 
LinkBack Thread Tools
post #1 of 5 Old 06-24-2019, 05:56 PM Thread Starter
xj2000cherokee
Registered User
 
Join Date: Apr 2018
Posts: 30
Is this the cylinder head that cracks?

Hi Everyone. After replacing my valve cover gasket the other day, I was finally able to get a better look at the casting codes on my cylinder head. I was hoping that someone along the way might have replaced it, but I don't believe that is the case and just want to confirm. It is definitely the 0331 head as you can see from the picture. The word TUPY is NOT found in the area under the oil cap. It does have NH3 cast into it towards the front of the engine. I don't know if that means anything or if the bad heads had that to begin with.

It's possible that in the future I might want to swap it out for the good head but just want to be 100% sure that this is the one known for developing a crack. Thanks.

Attached Thumbnails
DSC00167.jpg   DSC00168.jpg  
xj2000cherokee is offline  
Sponsored Links
Advertisement
 
post #2 of 5 Old 06-25-2019, 02:44 AM
Ralph77
Registered User
2000 XJ Cherokee 
 
Join Date: Aug 2015
Posts: 1,841
That is the one in the '00 and '01 XJ's that is prone to cracking.
Poor casting from the factory.
People say usually between cylinders 3 and 4.
Indicators are milkshake oil, little or no oil pressure at a hot idle, and unexplained loss of anti-freeze.
Some people say that it usually happened at about 75K to about 125K. If not in that range might be an indicator that it won't happen.
Some people seem to associate it coming about with overheating the engine.
Thinking it could happen at anytime. Not just within the mileage range above.
Some people have had this problem without cooking their engine.

With all that being said.
I think that this problem might be overplayed some.
Should you replace it just for the sake of replacing it?
If you don't think anything is wrong I don't think so.
If caught quick if and when it happens damage to lower end will be minimal if any.

I own an '00 myself. Not experiencing any of the symptoms.
Bought with about 145K 6 years ago with about 165K now.
I have no idea if it is the original head but is a 0331 non TUPY one.
Past couple years been putting her through some diagnostic tests to get a better handle on what condition my engine is in.
How do your plugs look?
Mine always look fine. I pull them to check every year.
I have put a mechanical oil pressure gauge on her and get 22 lbs at a hot idle.
My compression is good.
I did block test at a very hot idle. Fluid did not change color
Just for kicks am going to do a leak down test at some point.

In my travels have picked up a couple TUPY heads.
One I got for free and the other I paid $50.
Maybe they are good as is. Maybe they can be rebuilt. Maybe they are just door stops.
I figure if and when the time comes I might have it covered.
Ralph77 is offline  
post #3 of 5 Old 06-25-2019, 02:04 PM
axlaxl
Registered User
2000 XJ Cherokee 
 
Join Date: May 2014
Location: Brooklyn
Posts: 336
I had an 00 with that had and the 3-4 crack including the milkshake oil, coolant in the oil confirmed from a UOA along with serious metal degradation from the UOA. Ended having to get a rebuilt engine to avoid a catastrophic failure.

That being said, if you do not have any symptoms of a cracked head you prolly have no need to replace either the head or the block itself.

So just keep an eye out, maybe do a yearly used oil analysis from someone like Black Rock for peace of mind.
axlaxl is offline  
 
post #4 of 5 Old 06-25-2019, 04:55 PM Thread Starter
xj2000cherokee
Registered User
 
Join Date: Apr 2018
Posts: 30
Ok. Thanks for the great info guys. I hear so much about this head cracking that it makes me feel like itís a sure thing. At the moment Iíll periodically check for signs. Perhaps Iíll try to find a TUPY head as well to keep around just in case. Is the TUPY head a cylinder head that was manufactured by Chrysler in response to the problems with the 0331 casting, or is it an aftermarket cylinder head?
xj2000cherokee is offline  
post #5 of 5 Old 06-26-2019, 12:26 AM
Ralph77
Registered User
2000 XJ Cherokee 
 
Join Date: Aug 2015
Posts: 1,841
Quote:
Originally Posted by xj2000cherokee View Post
Ok. Thanks for the great info guys. I hear so much about this head cracking that it makes me feel like itís a sure thing. At the moment Iíll periodically check for signs. Perhaps Iíll try to find a TUPY head as well to keep around just in case. Is the TUPY head a cylinder head that was manufactured by Chrysler in response to the problems with the 0331 casting, or is it an aftermarket cylinder head?
TUPY head is a Mopar head. Can be found on WJ's, later part of '02 to '04, and TJ's, also later part of of '02 to '06.

There are other options. Clearwater heads being one of them. Many people have gone this route and seem happy with it.

The letters, TUPY, are very visible. If you are looking at a TUPY head there will be no doubt about it.

Seeing how when you buy a used head you don't really know the condition it may or may not be a good idea.
As far as cost goes.

Think of it this way.
You do not want to go through all that trouble putting on a used head without at least getting it checked by a machine shop.
Then when they do check it there is a chance it will need some work.
So by the time you are done with what you paid for the used head, tacking on what it will cost you to get it checked and maybe rebuilt, it might just be worth it to go buy a Clearwater one.

My thinking is I picked up the heads cheap or for free. Plus I have an in with the local engine rebuilder. They are a customer of the auto parts store I work at. On top of that they are pretty much the go to place in the area. Even with my in betting it will cost close to what a Clearwater one will. But I also like dealing with local people too. So much easier to deal with a problem if one should arise.

I guess what I am trying to say is do not let this keep you up at night. If you come across a TUPY head cheap sure why not. But I would not go out of my way to find one.
Just keep an eye on things.
And get an oil analysis done like axlaxl said. I should have thought to write that too.

https://www.blackstone-labs.com/?ses...swxr5%29%29%2F
Ralph77 is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the JeepForum.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.



Email Address:
OR

Log-in











Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome