I should have been in Chicago on Sunday, but instead I sit utterly defeated here at my house in Troy, Michigan. I’m covered in oil and coolant; lack of sleep has sprouted saggy bags under my eyes, which now stare blankly into this screen as my fingers bang out the words you’re reading with little input from my now barely-functioning brain. I have been defeated. All day Saturday and Sunday — the entirety of my weekend — involved me, a former Jeep cooling system engineer, being absolutely decimated by an overheating Jeep Cherokee XJ. I’m thoroughly annoyed, I’m thoroughly tired, and the buyer of this Jeep Cherokee may be thoroughly screwed.
I cannot even think back to the last weekend where I wasn’t fixing something. Truly, I think at least 90 percent of my non-travel weekends between age 24 and 31 (well, in two months) have involved wrenching on a shitbox. That’s seven years of my youth occupied by the ol’ wrench.
You’d think that the result of a youth spent with machines and not people my age would be an ability to fix damn near anything. And every now and then, like when I — even encumbered by a case of trenchfoot — revived a 1958 Willys FC that had sat for decades, I do begin to wonder if I’m hot shit with a toolset. But more often than not, any budding cockiness is swiftly crushed by the wrenching gods before it ever sprouts; that’s what happened this weekend.
It was a simple cylinder head job; I’d conducted the job four times prior, so I wasn’t anticipating any trouble from the beautiful 1991 Jeep Cherokee five-speed that I’d sold to the family that had ordered the Jeep from the factory way back in 1990. Sadly, 20 minutes after the buyer left with the title (no money has exchanged hands, she was going to wire it to me) to head back to Chicago, she told me the Jeep had overheated.
It was a tough call to get, because the amount of work I’d done to this XJ since going through hell to buy it back in 2018 — just to get it into selling shape — is shocking; The fact that the Jeep still isn’t finished made my heart sink. I was inching towards freedom; soon I’d no longer be weighed down physically and emotionally by American iron, but the AMC gods thought differently, and shoved the 9/16 swivel-head ratchet wrench right back into my hand.
You’ll understand why I was so bummed when you look at this list of repairs I made prior to the sale in April:
- Replaced front left fender (which I had professionally painted)
- Replaced front left fender flare (which I had professionally painted)
- Replaced front left fender liner
- Replaced front bumper (which I had professionally painted)
- Replaced rear bumper (which I had professionally painted)
- Replaced front axle
- Replaced front axle u-joints
- Replaced front ball joints
- Replaced steering tie rod ends
- Replaced steering drag link
- Replaced steering intermediate shaft
- Replaced steering box
- Replaced control arm bushings on front axle
- Replaced front axle seals
- Replaced front axle disconnect motor
- Replaced front wheel bearings
- Replaced front brake pads
- Replaced front left wheel
- Replaced all four tires
- Replaced all four shocks
- Replaced rear leaf springs
- Replaced driver’s seat
- Replaced driver’s door check-strap
- Fixed rear hatch interior trim
- Replaced front windshield wiper motor/transmission
- Replaced engine computer
- Replaced radio
Holy crap that’s a lot of work, and for what? So I could store the vehicle (which I considered the most perfect Jeep ever made when I bought it, with plans to keep it forever) for four years and only drive it a total of maybe 50 miles.
This XJ Cherokee ownership experience has been a failure in every way. I haven’t driven the Jeep, I’ve spent years fixing it, and once I finally had all of those repairs done and I thought I could finally part ways with this mechanical menace that had haunted me for far too long, the XJ decided to come right back and kick me one last time. And this time I’d be on the receiving end of the most painful blow yet.
After the Jeep overheated 20 minutes into the buyer’s (that’s Tracy) drive, she drove back in the car she’d piloted to Michigan, and I’d agreed to mend the engine. I heard a fairly loud knocking sound coming from the bottom of the motor, but once I learned that this was just the water pump banging around a bad bearing, I felt at ease. I could replace a water pump. Unfortunately, the Jeep wasn’t running properly; a compression check confirmed that the cylinder head had failed, and a machine shop later confirmed that it had cracked.
That brought me to this past weekend.
I had a freshly-shaved cylinder head ready to go, along with a new cylinder head gasket, new head bolts, a new water pump, a new thermostat, and a bunch of other replacement parts that typically accompany a head-job. After lapping the valves and swapping the valve stem seals for good measure, I threw the new head gasket onto the cleaned-off deck:
Then I maneuvered the absurdly heavy cylinder head onto the engine. I’ll admit that I didn’t get it aligned perfectly, and had to slide both the head on top of the gasket as well as the gasket on top of the deck. But the surfaces were smooth, and everything slid easily until I could get all my head bolts tightened up.
There’s a specific sequence one has to follow when tightening cylinder head bolts. It’s all about making sure that the head squishes down evenly on that gasket. I followed protocol, and then fastened up a new water pump and thermostat, hooked up the intake and exhaust manifolds, bolted up the power steering pump, slid the belt back on, connected the ignition system, filled the cooling system, and did a whole bunch more to get the Jeep finally ready to fire up.
After an initial ground strap issue, the Jeep followed the request from that ignition switch in the gray Saginaw Steering column and sprung to life. The motor sounded good. So that’s it, right? I’ve fixed the failed cylinder head, now the Jeep is ready to go to a new owner.
No.
As I said before, this Jeep is a menace. You see that list of nearly 30 parts I’ve already had to replace? This XJ is going to make sure the count hits 50. It is on a mission to take the remaining scraps of my youth and turn it into busted knuckles and oily bedsheets.
Despite my new water pump, thermostat, and radiator cap, the Jeep keeps overheating, especially at a long standing idle. Steady-state conditions where I keep speeds below 50 mph, it’ll run cool seemingly indefinitely, but crank the speeds up to 75 or come to an idle, and the need whips clockwise towards the dreaded red.
After buying a special funnel to ensure that the system was completely deaerated, I broke out a bunch of tools to determine what’s going on. The first was a radiator pressure tester. I screwed it onto my radiator, pumped the cooling system up to my radiator cap’s 13 PSI rating, and waited.
The needle fell, indicating that I have a leak somewhere. Sadly, that leak does not appear to be external, as even a close inspection of the radiator, water pump housing, and thermostat housing shows no dripping ethylene-glycol mixture.
The second tool I used was a “block tester” (shown on the left), which basically involves pouring a blue detection fluid into a cylinder, shoving that cylinder into the radiator, and sucking air from the cooling system through the blue fluid. If there are combustion gases in the coolant, they will turn the blue detection fluid yellow, meaning there’s a head or head gasket issue. My test fluid remained blue.
I also broke out my compression gauge, finding all cylinders to read between 100 psi and 120 psi — these are below the 120 to 150 spec, but maybe the gauge isn’t reading right. What’s more important with compression tests is consistency across all cylinders, and my engine has that, and does not burn any oil.
That brings me to the real problem: The motor does gain oil.
Yes, my oil reading on my dipstick is increasing. Between that and my lack of cooling system pressure, I suspect an internal problem. Do I have a cracked block? Did I somehow screw up my head installation? Maybe my bolts bottomed out or my gasket scuffed during installation? I don’t know the answer to these questions.
I may send an oil sample out to Blackstone Labs to have them confirm that it is indeed coolant in my oil and that I am indeed utterly screwed. Until them, I’m going to make a few other adjustments, maybe add some fuel injector cleaner to my fuel (lest I have an injector that’s leaking gas into my oil), tighten some hose clamps, and possibly thread a mechanical temperature gauge into my cylinder head for a more reliable reading.
This Jeep has been a nightmare since I bought it off that used-car lot in Indianapolis in 2018. I was lured by its beauty, its manual transmission, its awesome vent windows — but as they say, it’s what’s inside that counts, and this Jeep is rotten to the radiator core. Just yesterday while trying to suss out this cooling issue, I learned of a failed upper control arm weld, so I’ll be replacing that, too.
Have mercy Jeep gods. Let this just be a bad injector and a loose hose clamp. I don’t want to lift that heavy cylinder head off that engine. I really, really don’t. More importantly, I want to deliver Tracy a reliable Jeep; she’s in a pickle right now, as she was expecting this machine to work, and has no other car to get around. So the pressure is on.
First of all, hang in there, brother. We’ve all been there. In 1980 I bought an old house in East Tawas and, one Sunday night with the water off, I just could not get my solder joint to take. It was “make the joint, turn the water back on, find a leak, turn the water off and do it all again.” I was down to my last little bit of solder and, of course, there was no place to buy solder on a Sunday night in northeast Michigan. I cried. I swore. I prayed. But,eventually, I got it done. There was a reason my joints were bad, I just didn’t know why. (I finally became adept at sweating copper pipe). There is a reason your Jeep is overheating. You just know know that reason yet. You’ll get there, I’m sure.
Three weekends ago, my 2003 Outback overheated on the highway going to my parents’ house. No bubbles in the coolant reservoir, no milkshake oil, just a car that would rapidly overheat when standing still and then usually (but not always!) rapidly cool off when I got moving again.
Two weekends ago, I burned up a whole weekend and a couple hundred bucks replacing the water pump, thermostat, timing belt, and performing a coolant flush. It did not go smoothly—I had multiple water pump bolts strip out their holes the aluminum cylinder block, I got a timing belt with subtly wrong reference marks on it, etc. But I got it all done, and my fiancee even drove it to and from her farm for a week with zero issues. I also ran a compression test on the engine, and got 180 +/- 2 psi on all cylinders. Great, right? Dodged a bullet!
Last weekend, I drove it down to MA to return my parents’ 4Runner which they had very generously loaned me. Then, on the way back, it overheated again. Exact same symptoms… except this time there *are* bubbles in the coolant reservoir. God damn car had been hiding a blown head gasket the whole time. I mean, I know it’s an old Subie but I’d had the head gaskets replaced with the better-than-factory MLS ones less than 50,000 miles ago. I thought I was good on that, you know?
Now I have a car with a blown head gasket that is too old and worthless to be worth investing the time and money into fixing. Replacing the head gaskets on a Subaru is an engine-out procedure, and while I’m generally looking to level up my wrenching skills, this just doesn’t seem worth it. I admitted defeat, put a bottle of head gasket sealer in there (I promise not to sell it to anyone without making it clear that it has blown gaskets) and commenced looking for a new ride.
I’d really hoped to ride out this insane market with that Outback for a couple more years. Now though, my only trustworthy car is a 1996 Miata (glad I went with reliability when I bought a toy car) and I don’t drive that in the winter because salt. I need a new all-rounder, and I need it by October.
I’m currently thinking either a hybrid Maverick or an AWD Mazda 3 hatch. Pretty different, but both viable options and both at similar price points. The Maverick gets better gas mileage, has more shit-hauling capability, and offers a platform for DIY improvement. The 3 is more luxurious, has AWD, is still practical enough for my needs, and is just… unf. Gorgeous. So pretty. Lickable.
Anyway, that’s where I’m at. It’s been a ride, and I think I’ve made the right call admitting defeat in this case. Advice is welcome.
Sometime with an older engine that had the head off and then new gasket on the old block, would use a bottle of K-Seal or Blue Devil sealer to make sure things are good.
Wouldn’t use Antifreeze till I was sure things were working right.
Water in the oil won’t destroy bearings like Antifreeze will, when the motor is milkshake making mode.
Once the system holds pressure with Water, then drain and replace with Antifreeze.
David, you know what the Blackstone labs result will tell you, right? The thing rising in the dipstick is no oil, but blood – blood from the condemned leaking up from the pits of Hell into the jagged chambers of this cursed engine.
Have a look at the coolant level and tell me if it isn’t also rising… whatever was is in there before is now being diluted in the tears of the sinners from below.
Check the car history, I believe it will show that a previous owner decided to eschew a regular garage and just interred it in a pet cemetery, with a monkey’s paw in the glovebox just for good measure.
Time to call a priest of your preferred belief system. They won’t fix the issue, but they may contain the demonic influence from spreading to the rest of your fleet. Trust me, you do not want to face a possessed Jeep FC :-S
With that list of replaced parts, this is the Jeep of Theseus
As it is gaining ‘oil’ the coolant is either leaking at the head gasket or the block- I had this happen when a head stud was too long and went through the water jacket- if I remember correctly it was some AMC thing AMX or a Cherokee- or a VW Iltis, as it just started I would suspect that moving the head around messed up the gasket
Hey, what happened to you packing up your shit and heading to So-Cal?
Are you still looking to get a CDL to drive one of these babies?
https://en.wikipedia.org/wiki/Car_carrier_trailer
You decked the head, but if the block is a little warped then you will still have a small leak that is not a crack. Just a thought.
You know what time it is, we all know what time it is…
TIME TO LS SWAP IT!
I may be missing the point here, but what I take away from this article is that THIS JEEP MAKES ITS OWN OIL.
It’s easy to have old cars, but hard to have old cars that run; there’s always another issue coming including with stuff you thought you already fixed. This is not the right vehicle for that lady who doesn’t have sense enough to shut down an overheating motor or have any money anyway, she needs a 15-year-old Camry or something.
Not the easiest thing to say, but this is the closest thing to the truth.
Signed, a dude who’s owned (and wrenched on) over 40 old cars.
3 words: sunk cost fallacy.
At this point I feel you would’ve been better off sourcing a longblock from a junkyard with decent mileage and moving on…Those are like 500-1000 here.
Prep it with some 3-in-1 oil and get me a set of ball bearings.
It’s all about ball bearings now!
I saw one comment about reverse rotation water pump. I had a 1990 XJ with serpentine belt and am sure it was a reverse rotation pump. I think there is a casting mark on the pump housing iirc. I know it wouldn’t explain the rising oil level but might be worth double checking.
David, I just noticed something. You said that Tracy left with the title in her hand, but was going to send you the money when she got home. Did she ever pay you? I may have misunderstood, but, if no money has changed hands, tell her it cant be fixed, have her send back the title, and cancel the sale. Life is too short to keep banging your head against a brick wall.
I could be reading more into it than is there, but I think she NEEDS a car AND the car was originally purchased NEW by her family… DT’s on a mission from JEEP.
David always triumphs over Goliath, this time is no different.
Have you considered the radiator? I recently read an article authored by an eminent and respected former cooling system engineer. He was of the opinion that the radiator is of an inadequate size for the 4.0. If it’s clogged up with scale that will further impair its effectiveness. A $20 IR heat gun will let you read the difference in temp across the core, or you can just run your hand over it. You might try a flush or go big and have it rodded out by a rad shop.
That doesn’t explain the increase in oil level, which is concerning. I know everybody here is pussyfooting around the words “cracked block”, but that possibility can’t be dismissed. I think it’s unlikely that sliding the head around a bit to align it would have damaged the gasket.
Another long shot could a reverse water pump impeller. I’m not sure if the pumps interchange between the v-belt version and serp belt version of this pump without doing a parts lookup. I have seen this on both Ford and Chevy motors, but not sure if this is a reverse rotation pump or if they ever built a 4.0 with one. In twelve years owning a parts store, I saw a lot of stuff in the wrong box with the wrong part # on it that came right from the warehouse.
At any rate, I’m sure you’ll figure this out without my help. I just posted this to say that I’m enjoying the hell out of the new site. The lineup here is full of big hitters, and you all have hit a grand slam home run. The addition of Mercedes makes it nearly complete. Now if you could just get Fancy Kristen to come over from the dark side….
It would indeed be nice if they could get Kristen. Fingers crossed.
May I suggest a section called “symptoms” laid out somewhere with all the summary details we need to see in a bullet list to look over? Maybe put it in a nice decorative box labelled “symptoms”.
And, can we start an numbering system so we can keep track as time goes on. It would kinda be funny if you kept track of all the repairs done by the staff, with numbers. Mercedes is catching up fast, I’m sure.
What was the first repair???
David I know this isn’t very manly advice, but coming from a guy who has always been small and weak and is now old, small, and weaker, consider one of those $200 engine cranes from Harbor Freight to use for lowering your cylinder heads onto the block. (Chevy 6 guy speaking).
Or just ask the collective here to borrow one. I have a bluebird knockdown hoist unit along with a leveler, a truck to haul it in, and live 1 town over from DT.
Ive been here…
I was tired
I hadnt slept in 4 days
I was seeing brake discs and calipers in my head
My car was up on a self imposed lift — my wife was pissed at me cause she couldnt park her CAH in the right spot…
It took me 4 days to undo a SCREW… and I felt utterly worthless.
I spent 1 day calling around.. to have someone help me undo a damn Caliper bolt.
I now know.. I was at the end of my rope.. when it was starting to rain, I didnt care. I was worried Id never get my car going again and these stupid screws are making me crazy.
I couldnt undo the calipers.. they were fucked 3 ways to sunday.
Pads were shit
Discs were more warped than a big woman’s tittays.
I went to school… to pick up my Son, looking like I just fell off a Flatbed. I walked up to the most sensible stranger I knew.. and asked if they had a 20lb sledge. I told them of my problem. Dude knocked it out in 5min.— I felt like human waste.
Over the next week.. I put everything back together.
But… personally, between you and I… I would seek professional help. PREFERABLY FREE. PREFERABLY with a SLEDGE and BEER. Why….. cause ya going to ruin yourself.
One of these days DT is just going to wake up and notice that he has a giant “4RUNNER” tramp stamp on his back side. He’ll wonder what really happened the night before, and without a good memory of it, he’ll just take that as an omen bestowed upon him by the ancient Roman God Wrenchius. We all know what happens next.
Jeep ZJ > 4Runner.
Especially one with an AX-15!
Cracked block. Have it towed to the junkyard.
Drive to the nearest junkyard, leave it there and catch a bus home.
test