One thing OP, remember. You joined CherokeeForum where you will likely get all kinds of ideas, and that you bought a Jeep. It is a money pit by default, even in good condition!

 

I have a 2000 I have owned since new that was, until just recently, completely stock. I won't say I maintained it flawlessly, but I took reasonably good care of it. It developed the 0331 head crack. If I had it to do all over again, I would still buy the truck, but there are a couple of things I would do differently.

First, I would have sent an oil sample off for analysis on every oil change. The oil analysis tells you a tremendous amount about what's going on in your engine. It will tell you if water is getting into your oil long before you can see it with the naked eye. It will also tell you how the engine is wearing and can pinpoint other problems before they become serious.

Second, if I had known this model year had a history of head problems, I would have bought a combustion leak tester. This is a little tool that draws coolant up into a clear chamber to which you add some indicator solution that changes color if you have exhaust gases in your coolant. It costs about $50 from Amazon.

In my case the symptoms didn't always make sense. The truck would intermittently run hot for no apparent reason (not to the point of overheating, but it would sometimes run up to 240°). Flushing the system and changing thermostats made no difference. A water pump failed, leading me to believe that had been the problem, but the problem came back. Eventually I started seeing reddish brown sludge in the coolant. Then the water pump failed again. I replaced and had it flushed with a pressurized flusher, and the sludge came right back. All this took place gradually over tens of thousands of miles.

What was happening was that the crack would open under some loads, but not always. When it opened, it allowed hot exhaust gas to leak into the coolant, boiling it at that location. When coolant boils, the water boils out of it and leaves behind particulate matter that can't evaporate. If you see reddish brown sludge in your coolant, that's not rust. That's the precipitate out of boiled coolant.

The crack would be closed when the truck was just idling, so a coolant pressure test didn't detect it. A compression test might have, but I was focused on the cooling system and never tried it. I didn't notice a difference in the color of the oil until the very end.

Eventually I lost oil pressure and had to park it. In hindsight there were a number of things I could have done to save the block, but I really didn't know what I was dealing with at the time. When I would lurk on here and find other people discussing the exact same symptoms, usually the advice was to do exactly the things I had been doing. Because it took place over so long a period, I was ready to accept what seems to be the general consensus that these trucks just tend to run hot.

What I would suggest to the OP is that if you find yourself chasing unexplained cooling issues, don't panic and automatically assume that the head is cracked, but keep that in the back of your mind as a possibility and do what you can to test for it. Get the oil analysis at every oil change regardless. I use Blackstone, who charges $25 for the test. In between, watch for the symptoms I described. If you see what looks like rust in your coolant and it returns soon after a flush, take that seriously and consider testing the coolant with a combustion leak tester.

I would also suggest putting some money aside into a savings account dedicated to fixing things on the truck. Because even if you never have to deal with head problems, you will have to fix other things on it. Sometimes what starts as "repairs" end up as upgrades, and it's nice to have something put away for that. My head crack turned into a full engine swap for a stroker, which has in turn prompted me to jump in head first with a lift and a whole bunch of other upgrades that will give this truck a completely new life.

 

Extrashaky….Hey Thanks for all the advice I really appreciate your input. I will most likely just start saving as soon as I pay her off which isn't much. Hope for the best and plan for the worst! I will probably be changing the oil soon just to be on the safe side and get a test kit for it. Thanks again.

 

Thanks to everyone who replied. I have enjoyed driving her for the last two weeks and so has my wife…and yes all I have read have been horrors stories of the dreaded cracked head. I checked the oil again and no milkiness. I did a radiator flush today just to be on the safe side and all seems good! Its hot here in Texas now and she is still running at 210 degrees. The oil pressure is still good as well. I think I'm gonna go ahead and keep her, its in really great condition and very well maintained and the only thing I was paranoid about was this. Who knows maybe the last owner even fixed the problem (not holding breath). Again thanks to everyone for the reassurance! I have a 2013 jeep jku so I know that these little beast can eat threw your money because there is just so many mods that can be done! I was surprised my wife agreed to get another jeep haha.

 

Thanks I appreciate it. This is going to be a learning experience for me haha

 

Thanks for the reassurance!

 

I'm not sure where exactly but it's says 0331 somewhere on the head and if it has been swapped out it would say something different in the same spot. I'm thinkin you have to take the valve cover off to see it. I'm not 100% on this, it's been over a year since I've read about it

 

No symptoms = no fix. I'm not gonna send my oil to a lab when there's no problem. Coolant levels and oil condition tell you all you really need to know. Do whatever you feel you need to do. If mine ever cracks a stroker is gonna get dropped in so I really give a rats ***.

 

True about no symptoms no fix. Maybe every so often for piece of mind on my end.

 

Yea I saw it. It's on the outside of the valve cover on the driver side. I was just hoping maybe they reman the same head lol. All is well now. If anything happens I'll be sure to post it on here. Let's hope not thanks again for the info

 

No problem

 

Agreed about the lab work at every oil change. What a waste of money for a cheap vehicle. There is no way my heap needs more blood work than a human. Ppl just like to geek out over the lab results like an amateur chemist.

 

I agree that if you have no symptoms, there's nothing to fix. But the oil analysis can tell you if there's a problem before you have symptoms. You check your oil level, right? Under your reasoning, why bother checking the oil level if you haven't lost oil pressure? Obviously you do it as a preventive measure, expecting to see nothing wrong but just making sure. The oil analysis is the same thing, only higher-tech.

I now have oil analysis done on both my vehicles. It's cheap, and it tells you a lot about what's going on in the engine. I mean, $25 per oil change? How is that expensive? Even if you change your oil once per month, that's still not very expensive for the information you get. And if you were changing your oil that much, you wouldn't really even need to do it on every fill.

That was the plan for mine as well. I knew I had a problem and had actually already budgeted for the stroker in my build. But I had planned to do some other major projects first, and the crack forced my hand. I ended up swapping the engine on the truck's timeline instead of mine. Ten years ago, when I was making a lot less money, that would have put the truck in the junkyard instead and left me stranded.

My issue developed over a period years and thousands of miles. It's not necessarily like you get the crack and then you die. It can develop intermittently very gradually over a long time period. Having the info from the oil analysis much earlier would have helped me plan better for the eventual disaster. I'll say it again, I will never do another oil change without the peace of mind of an oil analysis.

 

Based on what I have seen and heard, the most consistent clue of a cracked cylinder head in a 4.0l is drop in the level of coolant in the overflow bottle. Of course assuming there are no external leaks. Put a mark on the bottle and check the level at least once a week.

 

$25 per oil change significantly raises the cost of an oil change. My oil changes now are close to 40 bucks with 6 fresh quarts of Rotella T6 5w40 and a good Napa GOLD filter. I change it every 6k miles. Whatever you do OP, don't put a Fram on your new jeep. I do think it would be beneficial for you to get the oil test done since you're new to this Jeep and all, but every oil change is a bit overkill.

But alas, let's not turn this into another oil thread. Oil threads become hot debates here (in case you haven't noticed).