I agree, if you decide the head gasket needs done I would at least get the existing head magnafluxed or just go ahead and get a clearwater head to put back on.

 

Everyone’s situation is different. I don’t have buy two new heads kind of money for a cheap Jeep toy.

My 0331 head gasket was blown. I pulled it, had it pressure Checked, shaved and I throw it back on. Engine ran great before hand and ran great after.

if this head last 3,000 miles it’ll last my lifetime.

but, had it been cracked I would have put a tupy or went with Clearwater.

pretty sure the places in between cylinder 3/4 are thinner. Not sure if you can eye ball it but good luck.

 

The usual 0331 head failure is the crack between 3 & 4 that lets coolant leak out the top of the head under the valve cover. I haven't seen anyone get pressurized coolant from the typical failure.

 

The absence of milky oil and the pressurization of the coolant has been an issue in a few other threads here...which is why I'm just swapping it (head) out. If it does not fix the issue then I'll be asking where the heck else could the exhaust pressure and coolant system be communicating? Coolant flows thru the head, if the head is cracked and communicating with the coolant, but not the oil, then the problem must reside in the head...this logic is so simple but if someone knows of how exactly one can have clean oil and high pressure in the coolant then please, I'm all ears. I'm not trying to be sarcastic btw...just trying to use logic to diagnose this thing,

 

The head must be cracked, all external seals are holding, I'm not losing coolant anywhere externally. As questioned earlier, how can this motor have clean oil, yet so much pressure in the coolant system? An update to my earlier symptoms, after running it for a few miles these last day or so, the brand new coolant in the brand new coolant system is no longer even close to green. So, either there's a location where exhaust can enter the coolant system after the head, or it's the head. And seeing as though virtually everyone with a 0331 says to replace when possible, I'm gonna replace, especially Bec I find it very hard to imagine how a gasket leak can take place between coolant and exhaust without a cracked head. If the head weren't cracked, then where else can coolant communicate with exhaust gases? See, just talked myself in a circle and that circle ends at the head. I'd love to be wrong, but this just seems too obvious not to drop $600 to keep this beautiful truck on the road.

Also, when I open the valve on the cap after driving it 5 miles, it pushes the cap up off the radiator so hard and violently that the outer seal on the cap doesn't hold and sprays out a bit in addition to filling the overflow tank.

 

a head gasket leak between the combustion chamber and coolant can pressurize the coolant.

 

Without oil contamination or external leaks from the head or block?

 

Pretty common on the first gen Equinox I had. Everyone that I knew had to do the head gaskets around 140k miles. My first symptom was quacking like a duck when I let off the gas. Then later random overheats as idle as gases built up in the head. The noise was the gases burping out of the head and out of the surge tank cap.

 

Very good to know! Thanks!

I'll report findings for sure...and I do hear gurgling on the passenger side every time I shut her down...so I'll be pretty excited to find no cracked head and a simple busted gasket. Pretty sure I'll still apply the Clearwater head tho...just DD if it's not cracked...I do intend on doing some off roading once she's up to par with my expectations.

 

Whether it's the head or the gasket you have to pull the head off and once you are that far it would be crazy to put the 0331 back on.

The only other place I know where combustion can get to the water is in the cylinder bores, but that is very unlikely except in rebuilds that have been bored way over or engines that have been overheated until they almost glow.

 

Thanks for the info and help in decision making...this thread has helped churn different thoughts concerning my decisions / plans for this XJ...in the best way possible. I've owned 1 CJ, 2 YJ's and a few later model Wranglers. The later model Wranglers simply don't hold the same nostalgia vs the earlier YJ's, and this Cherokee will help with that nostalgia when I NEED to put the kids in the car and just go. Once successful, I'll even post some pics, this thing is "pristine" underneath for a 21 yr old vehicle, and I'm looking forward to helping it maintain many more years of service.

Much appreciated all...I'll see you on the other side!

 

One last question...can anyone point me towards a part # for a good American made exhaust manifold to replace my original while I'm down there? or maybe point me towards a thread discussing a good manifold with part #?

 

New Clearwater Head

Relaxed day disassembling


Tomorrow morning the old head comes off (bolts already loosened) and the new head goes on. I'm going to use the stock exhaust manifold as the Dorman I bought looks to have lesser cavity for air flow and there are no obvious cracks in the stock manifold. On the way in I broke a fe brittle vacuum lines (will heat shrink them) and a connector to the air regulator on the cabin side (found all of the pieces so shouldn't be too much trouble to re-construct.

There was an obvious exhaust leak in the front most exhaust port, still looking for the crack but you guys know how this all goes.

The head I'm removing has the markings "NH2" and "99" under the valve cover looking up in addition to the "0331" along the driver side looking up.

 

Hard to tell from the picture, but how bad is the rust on those freeze plugs? Is that white lithum grease spoozed all over the bolts? Or did you **** off a goose?

 

the foaming version of PB Blaster. And they're rusty for sure but no deep pitting.