2000 XJ Cherokee cracked head advice
 

Hey guys! I am new here and not very experienced when it comes to working on cars or diagnosing issues so I am here looking for some advice on my jeep xj. It is a 2000 sport 4x4 with about 200k miles and it has either a cracked head or a blown head gasket. It has the 0331 molding as well.

Since buying it about 20k miles ago, it has always had a slow coolant leak and seemed to run a little hot, at about 210.

Recently after driving for a few hours on the freeway on a hot day I hit some traffic and when I came to a stop the temp gauge shot up all the way. The car continued to run fine but I quickly pulled over and let it cool down.

The next day when it was cold the coolant level was very low in the radiator so I topped it off (about 1/2 gallon was needed) and drove home, about 150 miles, and no issues except it was running about 220 most of the time.

I took it to a shop where they did a block test with the blue combustion leak fluid and confirmed that either the gasket is blown, the head is cracked, or both.

I do not want to spend the 3k they wanted to replace the head, nor do I want to spend the 5-6k on a new engine. I am open to trying to replace the head myself but I simply cannot afford it at this time.

I checked the oil level and is definitely past the full mark by quite a bit, and the inside of the oil cap has white residue and the oil looks like chocolate milk, so after doing some research I trust that the shop was correct and that I do have either a blown gasket or cracked head.

I cannot afford to fix the car right now, but would like to preserve it as best I can until I have some money to fix it properly. I have another vehicle so I don't mind letting this one sit for a while as long as it is not going to cause further damage to the engine. I plan on draining the milky oil and refilling with new oil so that is not sitting the way it is now.

Are there any other recommendations for things I can/should do if I plan on having the car sit for 6-8 months? Should I drain the cooling system too? If so should I leave it empty or refill that with clean coolant? I don't see signs of oil in the coolant, but there are definitely signs of coolant in the oil.

If the head is cracked, would I be better off with an entire new engine or just swapping out the head and gasket with new ones? I am looking at a new Titan head, but wondering if a brand new head will cause more issues if I put it on an engine with 200k miles. If I do replace the head are there other components that should be replaced as well?

Thanks for the time and any advice everyone!

A new head will take care of the top end, but what concernes me most are the crank and cam bearings. Continued driving with coolant in the oil will wipe them out eventually. Youve been driving it for the last 20k miles with unexplained coolant loss + the 0331 head, so i say expect the worst and start saving up.

I would drain the coolant and leave it drained. After changing the oil I would run it for a few seconds to burn off any antifreeze in the cylinders and purge the pudding out of the bearings.

You could periodically circulate oil as well by turning the engine over without the spark plugs in.

An oil/antifreeze mix creates organic acids that will pit the bearing surfaces and cause rust and tarnish so you got to get that stuff out of there.

If you had/have good oil pressure and don't hear any racket the block might > should be OK.

Why not start tearing it down now to assess the damage?

Meanwhile start looking for a used replacement head. Given the time frame you might find one cheap and be able to do the job for ~$250 (50 bucks for gasket set and $200 for head).

Use http://www.car-part.com to search there's a ton of them out there.

Make sure it's a TUPY 0331.

Also list your location. There may be a member near you who would be willing to help.

This. ^^^^^

Thank you for the advice I will definitely drain the coolant as well then.

Honestly I am not very mechanically confident, which is why I haven't started any work on it yet. I'm not sure I would be able to asses what the damage is even done when I do have it open because I have never worked on cars before and am not sure would be able to asses it properly.

As for oil pressure, it was definitely a little low at idle, but would increase when I would accelerate. Sometimes when I would start the car when it was really cold out the oil pressure gauge would shoot all the way to the right, and then I would usually just turn the car off and try again and it would go back to normal/slightly low.

I didn't hear any rattle in the engine though, at least nothing I was able to recognize as another symptom. It has always sounded pretty good to me and always about the same since I bought it.

Northern California, Humboldt County

Thank you for the advice I will definitely drain the coolant as well then.

Honestly I am not very mechanically confident, which is why I haven't started any work on it yet. I'm not sure I would be able to asses what the damage is even done when I do have it open because I have never worked on cars before and am not sure would be able to asses it properly.

As for oil pressure, it was definitely a little low at idle, but would increase when I would accelerate. Sometimes when I would start the car when it was really cold out the oil pressure gauge would shoot all the way to the right, and then I would usually just turn the car off and try again and it would go back to normal/slightly low.

I didn't hear any rattle in the engine though, at least nothing I was able to recognize as another symptom. It has always sounded pretty good to me and always about the same since I bought it.

If the crank and cam bearings are shot would it be better to just get a new engine altogether? How would I diagnose their integrity when I remove the head? I have never even seen any of those parts before so I wouldn't know what to look for.

I really do love this car. It is completely stock and someday I would love to turn it into an full on off road rig, and like I said I have another vehicle so even if it would take a couple years to save up for that kind of work if that is really the best option to keep it going for a long time I might consider it..

Otherwise if a new head, gasket, crank and bearings are a better/cheaper option I would consider that too.

Lots of miles/time with an antifreeze leak, high temperature for extended driving, high oil level and low oil pressure are all unfortunate signs. I would expect significant damage and almost certainly a cracked head. Cam shaft, main bearings, etc. is a lot of work requiring some experience with that type of thing and likely something you will not want to tackle. It may not be money well spent to have someone else start it as there is still the risk of significant cylinder wall wear due to oil dilution and 200k miles. Searching for a known good engine that can be swapped into your Jeep is one of the better options. A lower mile engine that was running when the vehicle was damaged in an accident would be a great find. You have time so begin a search.

It would be great if you can store the Jeep where it is not exposed to weather and critters. Put mouse traps around. I don’t think it matters much if it is stored with or without antifreeze. Antifreeze is a corrosion inhibitor and will help preserve the radiator and heater core. If it was me I would store it with antifreeze but not just water.

As far as your oil pressure goes, it's normal for 4.0 to be between 15 and 20 psi at idle.

One way to get a fairly scientific assessment of the mechanical health of an engine is to do an oil analysis. Your shop has already done a combustion gas test that strongly indicates head related issues (positive points for them as this is fast and inexpensive). The cost of oil analysis is around $30. Obtaining the sample it is quick to perform and requires no special skills or tools. An oil analysis will give an idea of how much water and antifreeze are in the oil and most importantly the wear metals present. Your sample will be compared by the lab to averages for this type of engine. If the metals found in the oil are many times higher than averages it helps confirm significant engine damage. The types of metal found is used to point to likely sources - cast iron from the block, lead from bearings, and aluminum from piston skirts. The lab report should break this out for your oil sample. If you take an oil sample follow the labs recommendations. If you see lots of metal flakes or glitter looking stuff in the oil you might just stop there as that is a bad sign of heavy wear/damage.

I have been very happy with Blackstone Labs. If they think your engine is in serious trouble they will tell you that in plain language along with their reasoning. You don’t have to be a materials scientist to decode the results. : www.blackstone-labs.com

It may depending on what is blown, cracked, etc. It could end up leaking into the crankcase and the effort to get it cleaned up would be for naught (assuming we're still trying to make an effort to save this engine).

If we're writing this thing off then don't waste money on oil and antifreeze.

That said, there is nothing KNOWN here other than you need a head gasket. The head could be OK or maybe it got changed out to a TUPY already. If we're going to make an assumption, IMO the assumption to make is the crank and cam bearings are OK until proven otherwise. I mean, we're talking a difference of $250 to $6000 here.

I need a signature... wait one.

How's this look?

No prob. Take a look at the job. I love these guys!

It sounds to me like the odds are against you having a solid engine. 20k with coolant loss, failing a combustion test, oil level rising, milky oil. I would plan for a new engine at this point, but as mentioned by another member you could have an oil analysis done. That will give you a total breakdown of what is in your used oil. Blackstone is about $30 now, and pulling the sample is pretty easy. Get the engine to full operating temperature, drain the oil and about halfway through the drain fill the supplied container with oil and send it to them and wait for the results.

So if you're still thinking about going this route, there's 3 critical things you're going to need:

1. Tools
2. Information
3. Skilz

Do you have a good set of tools? And that means not HFT.

A simple Google search and this forum should be able to provide all the information you need, but get the service manual https://cdn.xjjeeps.com/pdf/en-us/20...ice-manual.pdf and I have an extra Haynes Manual if you want.

Acquiring skilz takes time, but keep an open mind when attacking problems and think before you act. IMO it would most helpful to learn everything there is to know about nuts and bolts. How to remove them w/o snapping them, what to do if you do snap them, which bolts you can lean on and not worry (10.8s) and which ones break if you look at them wrong, which need torque wrenches (ft or in-lbs.), when to use 6 pt. sockets (always, unless you can't), use of PB Blaster and heat...

I suppose all information is good information, but if you're really short on coin instead of getting the trendy Blackstone report for $30 I'd spend $28 and get an oil pan gasket and and a Plastigage set. Yank the pan (p. 9-107 in the service manual)(they say pull the engine mount bolts, you can also droop (yes droop) the front axle) check the bottom for debris and pull a couple of rod caps. Inspect them and check clearance. If they're fine you've just saved $5750.00.

IMO working on Jeeps is more fun than driving them, the skilz you gain will save you literally tens of thousands of dollars over your lifetime, and the reward of personal accomplishment is what life is is all about.

I don't believe burning a small amount of antifreeze hurts anything (BTW since it's been doing it since you got it it might not be 20K it could be 140K). All it does is clean the spark plugs. That said, it won't be 6 spark plugs, it's only going to be 1 or 2. Pull them, mark the cylinder numbers and examine them. The clean ones will be where the gasket is blown or head cracked.

After you clean the pudding out and put in new oil, check compression. If it's fine (betting $2.00 that it is) no worries re: cylinder wear.

BTW2 collecting a sample for Blackstone requires running the engine and sending the pudding back up into the engine. Bad idea. Results won't be accurate anyway cause your crankcase volume is God-knows-what.

Thanks for all the advice, I am going to change the oil and take a look at the spark plugs today. I assume it wouldn't matter which order I do those in would it? And how would I go about checking the compression after I change the oil?

Would it be worth saving the old oil for any type of analysis?

If this helps at all this is the oil level before I touch anything. It has been in the car for about 1200 miles.



https://cimg1.ibsrv.net/gimg/www.che...68ab1fa569.jpg

How would I check if the head is a TUPY?

Here are a couple more pictures I'll add in case it helps at all. The first one I can actually see antifreeze pooling on the top of one of the bolts in the engine..https://cimg7.ibsrv.net/gimg/www.che...4fb2566be4.jpg
https://cimg0.ibsrv.net/gimg/www.che...2d450f4549.jpg

The pictures help. I am disheartened to see what appears to be a significant amount of antifreeze mixed with oil on top of the head. That and the fact that the oil level is maybe approaching a quart high on the dip stick. Assuming your oil level would have been at full or a little below what I see seems to indicate maybe 20% antifreeze and 80% oil in the engine. Antifreeze/water is a lousy lubricant for an engine. And some of the water in the antifreeze would have evaporated as the engine ran.

Dave has given you good advice but I don’t have much hope for this engine, especially the bearings. And with that much oil dilution any wear surface, including cylinder walls, is at risk if it ran for more than a short time. The engine has suffered from accelerated wear, no question about it. A full picture of how much is unknown unless significant disassembly is undertaken. To address cam bearings the cam shaft has to be removed from the front of the engine, which normally involves disassembly of a portion of the front of the vehicle to have room to get the cam shaft out. Cam wear is especially of interest as I believe oil from the head runs down onto the cam bearings to lubricate them.

When you drain the oil save a half a cups worth should you decide an oil analysis is something you want to do. Try to capture the sample about mid-way through the drain process. The collection bottle should be clean and avoid getting crud in it as you remove it from under the vehicle. The oil does not have to be circulated prior to doing that. Just let the analysis company know how you did the sample. And the amount of antifreeze/oil in the engine is not a show stopper either as for the analysis they look at parts per million or various elements in the oil. It is a ratio so if you have one gallon or 10 gallons of oil it should not matter. By the way, Blackstone Labs will send you sample bottles at no cost.

You ask how to identify a TUPY head. Normally you can see “TUPY” cast into the head between cylinders 3 & 4, usually visible looking straight down into the oil fill cap. With all the crud in there the valve cover might have to come off to clean up the gunk and get a better view. Here is a good link with photos on identification of a TUPY head. https://wranglertjforum.com/threads/...upy-head.8112/

this is my ongoing thread for my '99 XJ

https://www.cherokeeforum.com/f59/bo...rst-xj-241192/

youll see that we also had to tackle a headgasket/cracked head issue in the fall.
its not hard to do and i took lots of pictures that hopefully can give you some guidance
also clearwater cylinder heads will do you right .

Junkyard engine $300-500 all day, in-out in an afternoon, done.

This is why I think it's a waste of $30:

First, the concentration will be inaccurate because you've changed the dilution. You suddenly have added 2 quarts (Or more. Or less) of antifreeze. So your numbers might be off ~40%.

Second, and most importantly, we must differentiate between dissolved and particulate metals. An unmixed mid-stream sample might have dissolved metal, but since we're dealing with a sudden catastrophic event we are more concerned with particulate matter. If his engine is toast as some people suggest, there is going to be metal dust (hopefully nothing bigger) in the bottom of the pan. I suppose you could get a feel for this (so to speak) by sticking your finger in there and seeing if there's metal sludge (depending on the size of your finger). But IMO we have to pull the head and yank the oil pan. If the bottom of the pan and the rod bearings look good and there wasn't any noise when running last, I think just a head change will be a viable solution.

Despite this being a catastrophic event it doesn't sound like the crank or cam bearings would be damaged, but if the pan is off this would also be a good time to put in a new oil pump (and consider a higher volume pump). It is not clear if the oil pressure was low or WNL from the beginning of the thread, but low oil pressure does not always equate to need new camshaft bearings.

Bottom line, pull it apart and get a good assessment.

Certainly a thought, but we may not have the appropriate skill level or tools here (yet).

BTW, when you get a used engine, do you put in new stuff (lifters, oil pump, head gasket, water pump, oil pan gasket, etc.) before you slap it in?

Uriah, I must sincerely apologize as after reading XwalkerX's thread I have realized that I have omitted a critical item.

Clearly, having a Fox to help you in your project would all but guarantee success.

Cam bearings have a hole to receive oil from the gallery:

https://www.quadratec.com/sites/defa...ages/67735.jpg

IMO the great majority of cam bearing problems occur from severe sustained overheating. Then they kinda weld themselves to the camshaft and "spin".

I'm still thinking that this could be a $250 (relatively) easy job, with the aforementioned checks. If the rod bearings are good, the crank bearings should be good. And we can still pull off a or all the mains to check crank bearings (as an aside I'm surprised that Uriah hasn't asked "Hey, if I've got all the old rod bearings out why don't I just put in new ones?"). And if those bearings are good I think it's a safe bet the cam bearings are fine.

Anyway let's go back to the original post. We're operating on a very tight budget here, a somewhat limited skill set and an engine with 200K. If we can get a good head at a good price and the engine blows up 100 miles later (IT WON'T!) we can still sell the head and be out only a minimal amount of money. So sure the best answer from a purely mechanical point of view is let's get a new long block and have have someone install it but from a practical point of view that might not be possible.

Y'know, to me, that just looks like plain ol' oil. I can read at least the "SA" so there's some degree of transparency. Take a picture of it once you get it into the pan. Doesn't make sense about the overfill, but we're still in information-gathering mode.

Did you know aboot the 0331 head when you bought it?

You're Canadian, eh?

you betcha

I want to take a minute to minimize any misconception regarding the potential value for oil analysis in general and the worth of a diluted sample. True, if the sample is significantly diluted this will result in some error. The question is how much error and is it significant. When the sample is prepared by the analysis lab a very specific amount of oil is drawn and diluted with a specific solvent before it is tested. Blackstone has used 1 part oil and 8 parts solvent. As a result, error due to dilution in the sample taken from the engine is reduced by this 1:8 factor when the sample is tested. Even assuming Dave’s proposed 40% dilution of oil by antifreeze in the engine the sample as tested with 8 parts solvent added the concentration would be more like 5% off. A few percent error is insignificant when looking for several times greater wear metals from averages. If you tell the test lab about potential dilation they may take that into consideration when providing a summary.

As discussed this particular situation may not be the best case for a one-off oil analysis. If there is visible metal flakes (glitter) in drained engine oil it is serious. I would call that a show stopper for that engine. It indicates very heavy wear and a filter that likely went into bypass due to being plugged with contaminates. I have experienced this situation first hand on another vehicle (not a Jeep 4.0). If no obvious wear debris is seen in the oil sample analysis can be part of the overall evaluation process.

Oil analysis is most useful when performed at routine intervals and results evaluated for a change in the trend. This will alert you that something has changed from normal wear rates for that engine and an investigation can begin before something becomes catastrophic. It only takes a few minutes and is very easy.

Even a first time oil analysis is valuable. Based on an oil analysis I was able to identify a cracked head on my 2000 4.0 before it showed any obvious symptom. Analysis identified elements of antifreeze in the oil and slightly elevated wear metal. Based on this I investigated and discovered a small crack in the 0331 head. It appears that the head problem was caught early before serious engine damage occurred. Future oil analysis will help confirm. On a ’91 Cherokee I did an oil analysis before I bought it and that identified an oil dilution by fuel. That type of info is very valuable when making a purchase decision and in determining a fair purchase price.

I have found oil analysis useful enough that I have begun performing an oil analysis every other oil change on most of my vehicles to establish a baseline and look for problems. I would likely not buy another used vehicle without getting an oil analysis first if at all possible. As an FYI I have no connection to Blackstone Labs or any other analysis lab.

Dave: thanks for the correction and info on cam bearing lubrication. The situation I was thinking about but misstated is with the cam lobes and lifters. Somewhere I came across info that indicated cam lobes can take a beating in the area of cylinders 3 & 4 in the case of a 0331 head crack in that area. This is possibly due to oil returns near the typical head crack location dropping high concentration of antifreeze onto the cam lobes. If anyone can confirm this it would be nice. I know on my cracked 2000 head there was a small stain apparently from antifreeze that headed to oil return holes in that area.

Fortunately if the head is off it is relatively easy to pull out the hydraulic lifters and inspect them. The surface of the lifter that runs on the cam should be smooth and have a slight convex surface. In my case they were like new.

Thanks again for the info on engine lubrication paths.

OST, I believe you could make the numbers work with no error at all, but not for the above (keeping in mind with only 1200 miles on that oil, I'm really not seeing what that would tell us about wear, we're more concerned about damage over the last 150 miles or so).

If Blackstone dilutes the oil by 1:8, they would multiply the measured value by the amount of solvent added to get the final concentration, i.e., let's say lead is 200 ppm cause we might have bearing wear. The sample you send is 100 ppm cause it was suddenly diluted by half (trying to make calculations easy as I am short on math skilz). So they dilute it with a known quantity of solvent, centrifuge the sample to extract the insolubles and multiply it by 9 and we're right back where we started from at 100 ppm.

However, if they found 50% antifreeze you could extrapolate that out and come up with 200 ppm again.

What would be very misleading would be a normal sample (which based on the view of that dipstick is what I would bet)(if someone wants to send Uriah $30). Best answer IMO is pull the pan, examine the bottom and take a look at a couple of rod bearings.

See close up, I'm really liking this, cautious optimism:

https://cimg7.ibsrv.net/gimg/www.che...89bec88fc2.jpg

Hey guys, sorry for the long delay in my response. Been really busy this past week and haven't had a chance to get too much done but here is an update. I will attach pictures below as well.

I changed the oil and oil filter, and have about half a gallon of it stored in a clean container so I still have the option of doing a test with that. I think at least 7 quarts drained out, and from what I can find it sounds like that's at least 1 quart too many. It filled my 7 quart drain to the brim, and I actually needed to poor some out towards the end because I thought it was going to overflow, which it probably would have by just a little bit.

After pouring about a half gallon into the clean container, I let the rest of the oil sit for a couple days in the pan with the idea that if I did so I could slowly poor the oil out and have any metal fall to the bottom. So after I did this I looked closely at the drain pan and unfortunately it did appear that there was not only clearly some coolant in it, but also some metal pieces as well. It looks to me like super super fine sparkles in the sunlight, although not a ton of them but more than I wanted to see. I also found a few larger pieces which were a little concerning as well which I'll add pictures of. What do you think of this and is it even worth it to continue working on this or does this indicate serious damage?

I also went ahead and rented a compression test kit and watched a couple videos but I wanted to double check here before I actually use it.

I took the distributor bar off, and pulled all the spark plugs and have them organized with cylinder numbers (with the one closest to the radiator as number 1 - wasn't sure exactly if that was correct or if that would actually be 6).
1-3 to me look a bit dirty/rusty while 4-6 were definitely noticeably cleaner (see pics)

I wanted to double check before I try to crank the engine though if there is anything I am missing. I looked up that the fuel pump relay should be pulled out, so I located that in the fuse box but I haven't actually taken in out yet. I also read somewhere that I need to have the throttle blocked wide open, but I do not quite know what that means or how to do it, I think I was looking at a wrangler video for that piece of info but I wanted to see if that was something I should do and how I would do that.

Are there any other steps I should take? I plan on pulling the fuel pump relay, attaching the compression test and starting with cylinder 1 and working my way back, turning the key 6 times per cylinder. Does this sound like the correct way to do this? If they all come back between 120-150 psi with a variance within 30 psi does that mean the engine should be ok? And if not does that mean I should just stop there and accept that it'll need a new engine altogether?

Thanks again for all the help in advance, here are some of the pictures:


https://cimg8.ibsrv.net/gimg/www.che...7100a43bc2.jpg
https://cimg1.ibsrv.net/gimg/www.che...2333e74c68.jpg
https://cimg6.ibsrv.net/gimg/www.che...9103d6b06b.jpg
https://cimg7.ibsrv.net/gimg/www.che...91760f7478.jpg
https://cimg9.ibsrv.net/gimg/www.che...2cff65558c.jpg
https://cimg4.ibsrv.net/gimg/www.che...c29c6185b6.jpg
https://cimg3.ibsrv.net/gimg/www.che...d5dbf73324.jpg
https://cimg8.ibsrv.net/gimg/www.che...939fa967d8.jpg
https://cimg1.ibsrv.net/gimg/www.che...9651eac48c.jpg




I

Yeah, that might be the deal-breaker. If that came out on a normal drain there could be a lot more of that in there.

Next drop the pan. It's pretty easy and good practice. My guess is it's one of those rod bearings we were gonna look at.

OTOH, I guess we are...

On the bright side, a couple of those plugs might be a little cleaner than expected, but not earth-shattering!

Darn.. I wish I had done that before filling up back up with new oil haha. Do you think I should do a compression test still or should I just put it back together, drain the new oil and pull the pan?

Lets assume that there is more metal where that came from in the oil pan, is that going to indicate more damage than is worth fixing?

I am just trying to figure out for now if there is a chance I can save the engine with a new head, or if I should just plan on saving up for a whole new engine.

We're really kinda at snowball's chance, but looking is free. Still have the old filter? Cut it apart and see what'she in there. That oil is no good and don't turn the engine over. Assess what's in the bottom of the pan. Pull all the caps. If the crank is gouged the motor would need to be pulled. If there's metal dust the motor needs to be pulled and flushed. Probably need new oil pump but take it apart to look. Conceivably that debris could be timing gear stuff and/or the cam spun. Start looking for good used engine with TUPY head. You can still get the job done for about $600 if you go that route.

There's a glimmer of hope in that apparently there was no knocking, so maybe the crank is still good, but at 200,000 miles have a REAL low threshold to bail out.