Hi everyone, I've searched for this and haven't really found any good answer. I have an '01 tj with the 4.0 engine. I would like to find out how to identify what head my engine has on it. I've read that the heads labeled 0331 are prone to cracking and that they were changed to a head labeled TUPY to fix the problem. Can anyone tell me for sure where are these markings are located on the head? Thanks in advance for any info!!
How to identify 0331 or TUPY head
- Thread starter Vulture
- Start date
Taken from Cherokee Forum:
The 2000 and 2001 4.0 came with the original casting 0331 head. The TUPY head was also a 0331 head that had been redesigned with a thicker deck. You can also buy an aftermarket 0331 head from Clearwater that has a thicker deck to prevent the cracks. All three of these are are 0331 heads because of the design of the ports, and all three of them have "0331" cast into them in the same spot.
If it's been replaced, there's a high probability that it has been replaced with an aftermarket 0331 head that has been redesigned with a thicker deck to prevent cracking. What you want to know is whether you have the original 0331, an aftermarket 0331 or a 0630 head from a '99 or prior.
For the casting number, look on the driver's side of the head near the center, and you'll see a number peeking out from under the valve cover, like so:
Again, the original will have this number, and the replacements with the fixed deck will also have this number. The only way you won't see "0331" there is if someone has swapped in an earlier head.
To find out which 0331 you have, shine a light down in the oil filler cap and look at the surface of the head between the #3 and #4 cylinders. Below is a pic another member here posted a while back of an original 0331 on the left, and a Clearwater 0331 on the right.
You'll notice that the Clearwater head (right) has a number cast into it between the #3 and #4 cylinders, near where the original 0331 liked to crack. The original 0331 (left) has nothing cast into that spot.
A TUPY head will have "TUPY" cast into it right there, like so:
The 2000 and 2001 4.0 came with the original casting 0331 head. The TUPY head was also a 0331 head that had been redesigned with a thicker deck. You can also buy an aftermarket 0331 head from Clearwater that has a thicker deck to prevent the cracks. All three of these are are 0331 heads because of the design of the ports, and all three of them have "0331" cast into them in the same spot.
If it's been replaced, there's a high probability that it has been replaced with an aftermarket 0331 head that has been redesigned with a thicker deck to prevent cracking. What you want to know is whether you have the original 0331, an aftermarket 0331 or a 0630 head from a '99 or prior.
For the casting number, look on the driver's side of the head near the center, and you'll see a number peeking out from under the valve cover, like so:
Again, the original will have this number, and the replacements with the fixed deck will also have this number. The only way you won't see "0331" there is if someone has swapped in an earlier head.
To find out which 0331 you have, shine a light down in the oil filler cap and look at the surface of the head between the #3 and #4 cylinders. Below is a pic another member here posted a while back of an original 0331 on the left, and a Clearwater 0331 on the right.
You'll notice that the Clearwater head (right) has a number cast into it between the #3 and #4 cylinders, near where the original 0331 liked to crack. The original 0331 (left) has nothing cast into that spot.
A TUPY head will have "TUPY" cast into it right there, like so:
There were supposably only 3 years of production 0331 heads that were susceptible to cracking, 2000, 2001 and 2002. All other 0331 heads should be good, but you never know what may have been installed on them.
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So if looking down the oil fill and I see no stamping on the cylinder at all, I have the original 0331 head? If this is the case, my TJ has the original 0331 head. Hope it continues to hold up!
Read that post over again. If you have ANY of the 0331 heads, it will have an 0331 casting on it.
The redesigned ones just have an 0331 TUPY casting.
I see the stamping on the exterior next to valve cover on drivers side as explained. But when I look down oil fill opening, there are no numbers or words. Nothing.
If I read this correctly: “
You'll notice that the Clearwater head (right) has a number cast into it between the #3 and #4 cylinders, near where the original 0331 liked to crack. The original 0331 (left) has nothing cast into that spot.”
A TUPY head will have "TUPY" cast into it right there, like so:
So the original is blank internally looking through the oil fill.
Sounds like maybe you have an original head in that case.
Lucky me, just one more thing to worry about! It’s been 144,000 miles issue free, hope another 144,000 is in its future!
My 2000 TJ was bought new and now has 215,000 miles with no issues. I had to replace the head gasket at around 190,000 so I had the head tanked, magnafluxed, and surfaced without any problems noted.
