I am looking to trade for a 2001 Grand Cherokee 4x4 and when I went over to check the head number I couldn't find it. I looked on m 93 before I left so are they in a different places? There was insulation there which I scraped back but still no numbers.

Second question is if it is the 0331 is there a good chance it will go bad with 120K miles on it?

This guys grand father bought the rig new and when he died last summer he willed to my guy who has put 30k miles on it and only problem was he heard a gurgling sound and took it to Big O tires and they put in a new radiator.

 

http://www.wranglerforum.com/f210/03...on-203997.html

 

Or take off the oil cap and look down between the rockers,If you see the word tupy cast in to the head its the upgraded head.If not its the normal 0331 head and the wj got that head 99-mid 02.

 

The Good one. Mine waited until 156K miles. The Bad one says 0331 where it says TUPY. Shine a flashlight down the filler cap hole.

 

Thanks, I will check it out.

 

I bought the "Clearwater" replacement and it doesn't say anything there, just on the outside by the manifold.

 

Having an XJ and being on that part of the forum for a few years now, they can go at anytime or mileage. Maintaining the cooling system is super important. Don't let it overheat. That's any engine of course but real important here. I think the actual percentage that crack is low but I personally won't buy one with the bad head. But that's me.

If you buy it, the first thing I would do is go over and or replace all of the cooling system parts and fluids.

 

The bad one has the casting number "0331" in the same spot as the Tupy head, on the top edge on the driver's side near the #4 cylinder. It doesn't have anything where "TUPY" is cast on the revised head, except maybe a crack if you're lucky.

 

That wouldn't stop me from buying one if the deal and condition were right. Then I would replace the head preemptively. Or maybe I'd run it and wait for symptoms of a crack before replacing it. Then I'd have a really great Jeep with the best ignition and fuel management system ever put on a 4.0L.

But I wouldn't recommend it to someone brand new to the 4.0L, anyone unwilling to learn the symptoms and watch for them, or anyone without the tools and mechanical inclination to replace the head if necessary. The sad stories we keep seeing here involve people buying their first Jeep completely unaware of the problem and finding out too late, when they've already lost the engine. Or finding out early enough but having to pay a shop $2K to swap the head for them. This is not a good motor for those people.

 

To the OP, here are some additional pics showing the location of the casting number. It's just behind the center of the head on same side as the intake manifold. It sometimes gets covered over partially by the valve cover, so it may not be easy to see. The original casting and the Tupy casting will both have this number in the same place.

Hope these help:

 

Good info everyone thanks and I have been around Jeeps with this motor for 10 years or more, just never a 2000 or 2001.

 

Good points