How big of a headache is replacing blown head gasket?

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k0m0d067

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My mechanic skills are fairly decent...my father was a professional mechanic his whole life, and a lot of it rubbed off on me over the years growing up...I do all the mechanic work on my own rigs when it becomes necessary...but fortunately I've never had to tackle a blown head gasket.

Since moving to Australia I haven't replaced the majority of my tools, as I haven't needed to, so what am I going to need, minimum, to do it? Anything out of the ordinary, aside from a good torque wrench?

Any tips/tricks/advice to share would be much appreciated...

'03 TJ 4.0, manual transmission, air conditioning...
 
Definitely not a hard job if you have some basic mechanical skills. Take pictures / label parts so you can remember where everything goes. A good socket set, torque wrench and maybe some plyers are really all you need, assuming everything isn't rusted up. Couple of tips:
1- spend the money on a good head gasket and valve cover gasket. Don't buy the cheapest ones you can find unless you want to do it again​
2- The back valve cover bolts are a pain to get to - a good extension and maybe a universal adapter will make it easier​
3- Replace the head bolts - they should never be re-used. They elongate when you torque them the first time and greatly lose strength it re-used​
4- spend the time to really clean up the mating surfaces of all old head gasket material. It doesn't take much to cause the new gasket to fail and leak​
5- The hardest bolts to get out will be the exhaust manifold. It may be easier (and less risk of snapping of the bolts) to remove the catalytic converter down pipe from the manifold. It those bolts break, it is as simple as putting in a new one vs. having to extract a broken one from the head.​
6- Eat your Wheaties - the head is heavy on the straight 6!​
 
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If you think you might add a turbocharger or supercharger in the future, this would be a very good time to upgrade the head bolts with ARP studs (or bolts). The studs will add strength and distribute clamping force better than bolts, reducing the odds of gasket failure in the future.

I seem to recall that the bolts can be reused once. If you’re confident the bolts have never been removed or loosened then you should be okay to reuse them this time.
 
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Find a good shop who will machine the head too.
When you tighten the head treat it just like you would a tire by alternating tightening each bolt. That way it will apply even pressure.
 
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Awesome, thanks folks!

I seem to recall reading somewhere about lining the exhaust manifold up, when reinstalling, being a huge pain? And the oerson recommended removing the fender to make it easier? Seems a bit extreme?
 
Remove the fender. It is fast and easy. It will make the manifold a breeze and give you ample room to work. It will probaly save you time and if not if will definitely save you some frustration.
 
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Dredging up an old thread here, someone told copper head gaskets are the way to go with engines like the I-6. Do they make copper head gaskets for our engine? If not, what's the best one to go with? I definitely don't wanna do this twice haha
 
Craig 06 TJ said:
Dredging up an old thread here, someone told copper head gaskets are the way to go with engines like the I-6. Do they make copper head gaskets for our engine? If not, what's the best one to go with? I definitely don't wanna do this twice haha
Click to expand...
Mopar is under $40 at rockauto, you would probably be fine with the $10 ultra-power as well, it's not like this is a high performance engine. I'd probably use the factory Mopar part since the job is so big anyway and it isn't too expensive. I wouldn't use anything fancy like copper, seems like a waste.
 
I’ve done many many head gaskets on in-line diesels, never a 4.0 though. The one trick that stuck in my mind was not to remove anything more than is absolutely needed to get the head clear. I’ve had several engines that after disconnecting the intake piping and exhaust pipe, along with hoses and wiring, I pulled the head with the manifolds attached. No idea if it’ll work in a Jeep, but it might!
 
If you're looking for gaskets that can survive forced induction or other modifications, consider buying ARP head studs instead (or in combination). The studs are stronger and have better clamping force, thereby reducing the odds of blowing a gasket.

https://www.amazon.com/dp/B00E5YSKBS/?tag=wranglerorg-20

If you're not adding forced induction or stroking it, I wouldn't bother.
 
Steel City 06 said:
If you're looking for gaskets that can survive forced induction or other modifications, consider buying ARP head studs instead (or in combination). The studs are stronger and have better clamping force, thereby reducing the odds of blowing a gasket.

https://www.amazon.com/dp/B00E5YSKBS/?tag=wranglerorg-20

If you're not adding forced induction or stroking it, I wouldn't bother.
Click to expand...

Having gone down this route, an MLS headgasket is what you want. The cheaper Felpro head bolts are strong enough and allow you to keep the mounting clips that clip on the head studs. The ARP head bolts are plenty too, the ARP head studs are overkill and more difficult to work with.
 
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My first question is how do you know it is a blown head gasket? The job is fairly straight forward with hand tools, but the 4.0L usually doesn't blow the head gasket after an overheat event. The ones I have seen that have been severely overheated have either cracked or warped the cylinder head. Neither of these problems would be fixed by simply replacing the head gasket. I'm not saying your problem isn't a head gasket, but if doing the head gasket I would confirm the other two potential issues to not be a problem during this repair, or you will be pulling it apart again.
 
This can be done in a few hours, there are a few write ups, might want to do your thermostat and water pump while your in there
 
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I'm definitely worried about what I'm gonna find while I'm in there, but I'm hopeful that it's just a head gasket. I have wet spots all around the head. Not sure what to look for though.
 
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