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0331 - cylinder head - what years?

ckndrob

NAXJA Forum User
Location
maine
Hi,

Can someone tell me what years on the Cherokee and Grand Cherokee did Jeep use the 0331 cylinder head?

Thanks
 
2000-2001. Some say there could be late 2001's with a different number. I only know about XJ. There is tons of data on the forums about this issue. For what a head replacement costs I wouldn't pass up a special Jeep because it has a 0331 casting if it has no issues and has had good maintenance.
 
All 00-01 XJs have the 0331.

It was sometime late in 02 for the Grand Cherokee before they switched to the new casting from TUPY (Brazilian foundry).
 
It is very easy to spot a 0331 head. If the head has the coil pack over the spark plugs, and no spark plug wires, you have a 0331. The XJ went End-of-Life before the TUPY head was introduced. The introduction happened sometime in late 2002 on both the Wrangler and Grand Cherokee. If you remove the oil fill cap and look straight down at the floor of the head, between the cylinder 3 & 4 exhaust rocker arms, you can see the text string "TUPY" cast into the head. This is a casting mark and not stamped as many other threads have claimed.

If you don't see TUPY there, you may see a narrow row of green bubbles, following the curvature at the bottom of the #4 exhaust rocker boss and #4 exhaust valve sping boss. You can look through the oil fill cap and determine if the head is either cracked, prone to cracking, or that it won't crack in the future.
 
I'm looking at a 2001 tomorrow with 91k on the clock. Anything I can look for to see if there 'may' be an issue with the head?

Thank you!

-- Warren
 
I'm looking at a 2001 tomorrow with 91k on the clock. Anything I can look for to see if there 'may' be an issue with the head?

Thank you!

-- Warren

Check the condition of the coolant, radiator & overflow bottle. If its dirty/brown then chances are the cooling system was neglected & the head could've overheated & cracked. Also check the oil filer cap & see if there is any milky residue as a sign of potential coolant in the oil. Check oil for milky residue. Just a few things I can think that "could be" signs f a cracked 0331 head.
 
Thanks my friend - She's a real cream-puff so I am hoping all is in order and will probably jump on it and tuck away some money just in case, and keep an eye on her.

-- Warren
 
Thanks my friend - She's a real cream-puff so I am hoping all is in order and will probably jump on it and tuck away some money just in case, and keep an eye on her.

-- Warren

Warren, if you buy this one, as long as you open the hood at LEAST once a week to check the coolant level in the coolant reservoir, you should be fine.

Commit the following sentence to your memory:

The #1 symptom of a cracked 0331 cylinder head is "unexplained coolant loss".


So if you need to add coolant and can't find a leak with an inspection, suspect a cracked head.Certainly not all with the 00-01 will experience a cracked 0331 head, but enough do to make it a very viable concern. And if you catch it early enough, verify it and pop on a revised head (never just install another older 0331 head), you can prevent the rest of the engine from damage. Coolant in the oil from a cracked 0331 head will toast your engine bearings in pretty short order.
 
Warren, if you buy this one, as long as you open the hood at LEAST once a week to check the coolant level in the coolant reservoir, you should be fine.

Commit the following sentence to your memory:

The #1 symptom of a cracked 0331 cylinder head is "unexplained coolant loss".

So if you need to add coolant and can't find a leak with an inspection, suspect a cracked head.Certainly not all with the 00-01 will experience a cracked 0331 head, but enough do to make it a very viable concern. And if you catch it early enough, verify it and pop on a revised head (never just install another older 0331 head), you can prevent the rest of the engine from damage. Coolant in the oil from a cracked 0331 head will toast your engine bearings in pretty short order.


+1, Keep your cooling system working properly & you should be OK. Most 0331 problems usually arise after an overheating incident.

I am approaching 140K on my 01 & all is well, I flush out/fill with new coolant/change the thermostat/radiator cap every 2 years, Hoses & belt every 3 years. Even quality long life coolant starts to look like crap after a couple of years

Also keep an eye on the temp gauge & make sure the fans are working properly. My temp gauge was creeping up a little last summer, I checked it out immediately & found a burned out aux fan.

Keep the cooling system in good shape & the 0331 should be OK.
 
Last edited:
+1, Keep your cooling system working properly & you should be OK. Most 0331 problems usually arise after an overheating incident.

I am approaching 140K on my 01 & all is well, I flush out/fill with new coolant/change the thermostat/radiator cap every 2 years, Hoses & belt every 3 years. Even quality long life coolant starts to look like crap after a couple of years

Also keep an eye on the temp gauge & make sure the fans are working properly. My temp gauge was creeping up a little last summer, I checked it out immediately & found a burned out aux fan.

Keep the cooling system in good shape & the 0331 should be OK.

Good advice - However being an SE it only has idiot lights so I'll need to implement some upgraded gauges ASAP...

Either looking at trying to find a Sport cluster, or perhaps adding the Garmin ECO HD package to my current GPS... :read:

-- Warren
 
So am I straight with the 99'-01 XJ's and 99-02 WJ's having the 0331 head?

I get maintenance of the coolant system is key..but I don't want to take the chance of my daughters overheating the thing and creating a bigger issue with a 0331 failing on me.
 
So am I straight with the 99'-01 XJ's and 99-02 WJ's having the 0331 head?
00-01 XJs have the 0331 head. 99-04 WJs have the 0331 head. In 2003 (some say 2002) they had the revised "TUPY" head.
 
I have an 00' and experienced the crack cylinder head issue and do not want a repeat which is why I am trying to sort the years the 0331 were used.

I want to buy another Jeep and want to avoid anything with an 0331 on a Jeep my kids will drive in case it overheats.

So I was looking at some 01' and 02' Grand Cherokee's but looks like I should move my search into a later model like an 03'
 
check weekly!? My 01 has like 240,000 hard miles on it and unfortunately has been overheated a few times.. And even had water sucked into it.. ( pulled plugs cranked and watched water spit out) and it stil runs like a top..

where I'm at they are readily available and usually in the best shape
 
0331 head cracking is the topic of far more Internet threads, than actual 0331 heads have cracked.

Warren, if you buy this one, as long as you open the hood at LEAST once a week to check the coolant level in the coolant reservoir, you should be fine.

Commit the following sentence to your memory:

The #1 symptom of a cracked 0331 cylinder head is "unexplained coolant loss".

The #1 cause of coolant loss/overheating is owner neglect and failure to perform routine maintenance of the cooling system.

120,000 miles on my 0331 head and I would buy another well maintained 00-01.
 
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