mannydantyla

There's no outward sign of coolant leaking into the oil but I guess it really is. There's no visible oil in the coolant, no visible coolant in the oil, no white smoke in the exhaust, no coolant lose that I can detect although I will admit that I've been changing the coolant so regularly that it doesn't have time to drop. I've been flushing the cooling system aggressively hoping that will fix my overheating problems. It only overheats on the highway after an hour or two, in the summer. Only 3 or 4 times has it boiled over and the needle has spiked into the red.

Here's my results:



Here's what they SHOULD be with the same oil:



Here's another oil sample from a Jeep 4.0L with coolant in the oil: https://jalopnik.com/how-a-28-labora...ine-1795355769
And another: https://www.cherokeeforum.com/attach...kee-101412.pdf
And another: https://www.cherokeeforum.com/attach...-xj-170224.jpg
Another user said: "It's similar to my report. I had a cracked head."

.................

I guess what I'm wondering is, and what I need advice on, is it worth all the trouble of replacing the head gasket or, worse, the head itself?

Engine has 254,000 miles on it. Before me, it was owned by a middle-aged lady who bought it new in 1997. And I have a huge stack of records and receipts that shows it was well maintained and always had everything serviced regularly.

I did a compression test and all 6 cylinders show 140 to 150 psi.

The large amount of lead and copper in the sample is alarming and are probably the crank bearings wearing down abnormally fast. But there's no way to know who warn down they actually are without visually inspecting and measuring them.

If I need a whole engine rebuild then I'm going to say **** it.

I've put a TON of energy, time and money into this Jeep. Just last week I replaced the alternator, serpentine belt, and radiator (it had some black, gritty sludge in it, which I was hoping was the cause of my overheating problems, but I don't know any more).

What if I put some kind of bars stopleak into it?? I mean, it looks like a small leak and the engine might not have much to loose. And what if fixing this tiny leak doesn't fix my overheating problem? I mean, it's still possible that the cooling system simply isn't adequate. I put in the single-row radiator from Spectra, which has a lot of good reviews but it isn't the best. That would be the $300 Mopar HD radiator.

How hard is it to replace the head? Compared to replacing the easier things like starter, alternator, brake pads, fuel injectors, shocks, etc. which I've all done myself.

mannydantyla

I think I'm going to try a low-risk stops leak like "steel seal" and then go for a loooooong test drive. The crack/hole in the head gasket can't be that big. I mean, it wouldn't take a miracle.

I know what you're thinking and I don't like cheap fixes either, but this might be one of the rare occasions where stops leak is applicable.

PatHenry

Coolant will do a number on the bearings and do so quickly.

I wouldn't put a stop-leak product into it unless you're planning on driving it a bit while shopping for a new vehicle.

Whether the Jeep is worth fixing or not is a personal decision that only you can ultimately decide. 250k is not a tremendously high on these engines (my dad's 94 XJ went 400k without issue and my 00 TJ went 300k with the 0331 head and still runs great.) but if you've got a lot of bearing damage already, then it may be done for. (Edit - what's the oil pressure like?) If it were me, I'd consider the rest of the vehicle and see if it's worth putting more time/money into. Is it low rust, does everything else run well, etc. etc.

I feel that you're capable of doing the head/head gasket replacement if that's the route you decide to go.

mannydantyla

Oil pressure is good. A little less than 40 while idling, a little more than 40 when cruising

No rust, engine runs like a clock, 20+ MPG on the highway, good interior, good exterior. Only thing I hate about it is the a/c doesn't work

Tbone289

In that case, I wouldn't hesitate to rebuild an engine for it.


At this point I would double-check the oil pressure with a mechanical gauge and if good, park it and pull the head off and determine the issue with the coolant leak.


Got any extra vehicles to drive around in the meantime?

PatHenry

I'd follow TBone's advice. If you've got good oil pressure, very low rust and everything else works great, it's definitely worth the effort.

mannydantyla

Yes but...

What if I put the new headgasket on and I have done nothing to solve the overheating problem and it overheats again and cracks?

What if I just keep changing the oil every 500 miles until the engine breaks and then I get a new one? I mean, it's running fine, except for the overheating thing but I'm struggling to see how a tiny amount of coolant leaking into the oil can cause overheating.

What if I just sell the jeep the way it is? And get a toyota

What if I try to fix it and I **** it all up? My roommate tried to fix his GF's BMW that overheated and blew the head gasket. He replaced the head gasket, had the head machined, put it all back together and there was no compression at all. Block was cracked or something

What if I just need to torque down the head bolts?

I'm weighing the risk and reward, pros and cons of each

PatHenry

Totally reasonable thinking brother.

I wouldn't bank on the "just needing to tighten down the head bolts" though.

If you do decide to drive it and change the oil every 500 miles, you're still running a dangerous course with risking damage to the bearings. However, if your end game is replacing the entire engine, why not just do that straightaway and be done with it?

You could sell the Jeep as is and if the only things wrong are a bad head/head gasket and non-functioning A/C, you'll still get something for it. Low rust XJ's are desirable to Jeep guys (and gals). You could check around and see what the trade-in value is if you buy another vehicle from a dealer.

As far as putting it back together and having issues, I have to think that BMW's are a lot pickier than the Jeep I6. You don't hear of folks having frequent block cracking or failures when properly installing a new head or replacing the head gasket. Also since the Jeep I6 is soooo prolific, there's a lot of information and instructions on how to do the job. It's considered a very easy job on the I6 compared to other engines/vehicles.

If you're thinking to get a Toyota, that's a reasonable thought, but while Toyotas are generally very well made and durable vehicles, anything will have problems which escalate as they get older and have higher mileage. So it really depends on what you'd be looking at, new vs. used and "how used", etc. Also if you're thinking about a Tacoma specifically, be aware that of all the mass produced vehicles, the ones that retain value more than any other are Wranglers and Tacomas - so be prepared for the higher cost for comparable features.

Ultimately only you can decide what is best for you. We'll all be here for you regardless of what direction you go, even if you decide to leave the XJ owner family. If the Jeep has sentimental value to you or you absolutely love it, then fix it. If it's just another random vehicle to you, then consider every alternative.
For me personally, I'd never put nearly as much time and effort into my "family car" (even if I could) as I would into my Jeep - but that's me.

Tbone289

I guess I didn't realize there was an overheating history. Was that covered in another thread?


^ Good advice as always from Pat. I think I would install a junkyard engine and take some time and rebuild the one you have. I look at my XJ as more of a long-term ride though.

mannydantyla

Thank you everyone for your advice! It really does help

I just went on a test drive in brutal heat today (97*F). After 30 minutes of 75+ MPH, it started running hot and the temp gauge slowly went up to as high as 230*F. I slowed down to 65 MPH and turned on the heater and the temp stayed the same. When I got into the city, the temp slowly started to drop, even without the heater on.

The good news is I got 25 mpg, believe it or not.

Because I intend on driving this to New Mexico in about 6 weeks, and that's a 10 hour drive. I will be with my brother, we are on a mission to scatter our father's remains at his favorite fishing hole in the NM mountains.

I have a '09 pickup truck that runs great if I need a backup, but I really want to take this Jeep as I have been getting it ready for this trip for a long time. Over the winter when I assumed I had the engine problems were solved. I fabed my own skid plates, made a cargo/sleeping platform, installed some suspension stuff, etc. Just last week I installed a new alternator, battery and serpentine belt just for preventative maintenance, along with the new radiator.

The new radiator is a single-row aluminum one made by Spectra. It has good reviews, but its actually thinner than the previous one (that had some black crud in it). I could get the Mopar HD one but it's $300!

Sorry I didn't make that clear

here's a very brief history:

It all started last summer (first summer after buying it, so I don't know if there was a problem before or not) when the radiator exploded when I pulled off the highway to get gas. I did notice the needle was getting a little above normal before the rad burst open. I was towed home and I put in a new radiator, but I found that it was now overheating on the highway after 20 minutes or so.

I replaced the rest of the cooling system and started aggressively flushing the rust buildup out of the coolant passages and it got better, now it only overheated after several hours of highway use. I figured the new radiator was clogged with rust scale and stuff, so last week I swapped it out. I cut open the old one a yeah there was some black crud in it. But a few days ago I went on a 30 minute highway drive and it started getting warm again, like 230*F. I used the heater core to lower it back down to normal temps and drove slow on the way back home.

mannydantyla

I want to come up with a plan ASAP in case I have to order parts. 6 weeks and counting till my trip.

Here's what I'm thinking is happening: it is a blown head gasket and it is causing the overheating. But it is a small leak, maybe the head is warped just a tiny bit, and when the engine is cold and not running, it's sealed up and that is why compression appears to be good and no combustion gases can be detected in the coolant.

However, once it's warmed up and been on the road for a while, that's when it starts to leak. When the cylinder fires it will leak under much higher cylinder pressures than when I'm simply cranking the engine when testing for compression. Or maybe thats all BS because when the engine heats up the metal and the gasket should all expand and seal any gaps...

I have two choices:

1. hope and pray that I'm correct and get a new head gasket. Will need to take the head to a machine shop. There's a good one near me but it may take a month if he has a lot of business right now.
2. or, try Bars liquid head gasket fix or similar. If it doesn't work then sell the vehicle and buy another 4x4. The engine may already be ****ed anyways but it runs really well right now

I don't know man i really don't...

Tbone289

Here are my thoughts:


#1. Why not just pull the head now and not assume (or hope and pray)? If you pull the head and don't find an issue with the gasket, then at least you'll be one step closer to diagnosing the real issue. You have to be somewhat skeptical about the gasket being the problem anyway, since your compression numbers were good.


#2. This sounds like a really bad idea to me, but I don't buy into quick fixes for mechanical issues. Are you saying that when you get to the point where you have to rebuild or replace the engine, you're done with your XJ and moving on? You will get there eventually--if not now, later.


*DISCLAIMER* There are guys on here with much more experience than I have, so don't go out to the shop right now and just pull your head off based upon my thoughts. ;-)

mannydantyla

Alright I'm f*cking done being a p*ssy. I'm taking the head of tonight and ordering the new gasket right now

Maybe the engine doesn't have much life left but it has enough to get me on my next adventure

5-Speed

Post some pictures of the head gasket, top and bottom, once you pull it off and we can tell you if it looks like it was leaking anywhere. I would still find a shop to check for cracks in the head even if the gasket looks bad.

jpz

Always a fan of "I'm f*cking done being a p*ssy" posts. Good for you jumping in. Keep everyone posted on how you make out.

Semi related, not sure what the weather conditions in your area are like but if you decide to move forward with a Toyota, look very closely at the frame. There is a surprisingly large window (95 to 2010 if I remember correctly) where they have rust issues on the frame. Toyota extended the warranty and there are plenty of examples of people needing new frames. I personally know of 2 people that had to have the frames replaced on their Toyota trucks.