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Preemptively changing head gasket....thoughts?

gearwhine

NAXJA Forum User
Location
Denver, CO
1996 4.0L with just ~136k. I bought with 134k...

Current issues:

1) light rattling under load. I have a previous thread going on about this
2) coolant leak at front of head

Getting in there this evening, I finally found the exhaust manifold crack (which was suggested as a likely culprit of my rattling). The coolant leak was at the top of the water pump, and I mis-diagnosed it as a head gasket leak 2 weeks ago. With that, I preemptively bought everything I need to do a proper head gasket replacement.

So now... It's more or less all coming apart aside from the head, and I have all the parts. I'm very familiar with hearing about the commonality of head gaskets going on the 4.0L.

What are the thoughts of getting in there? I am pretty positive there are no issues with the head gasket at this time... I'd like to leave it alone, but I am having some major pull to just do it all.
 
If it aint broke, dont mess with it. Set the new gasket aside for when it is needed, or return it, or sell it.

You pull the head, well then you might as well do a valve job, right? when does it stop, how deep of a project do you want to inflict on yourself?

Fix what is broke, and enjoy the drive.

Hey if you had known the leak was the pump, not the head, would you have bought the head gasket then?

Sounds like you want to do the job simply cause you have the part. but what of the labor, and then consider two years from now you end up HAVING TO doing it again cause your leak down test says you need a valve job, or a lifter fails. So are you going to put a head with 134K miles back on without doing the valves too? I say hold off on the extra work, you may never need to redo the head with its existing gasket. if eventual the gasket fails, or valves need work, or you need a new cam, or lifters, that is the time you put a new head gasket in.

thats my take on it.
 
I have +284,000 miles on the same head gasket. Don't mess with it.
 
x2. As Black1990jeep suggests, this is a black hole and it will be difficult to stop at the head gasket. I did this on my '90 and ended up removing all the valve's, changing the valve seals and spent hours on general cleanup. In my case it helped me to get emissions down but I am not sure that all that work really helped much.



If it aint broke, dont mess with it. Set the new gasket aside for when it is needed, or return it, or sell it.

You pull the head, well then you might as well do a valve job, right? when does it stop, how deep of a project do you want to inflict on yourself?

Fix what is broke, and enjoy the drive.

Hey if you had known the leak was the pump, not the head, would you have bought the head gasket then?

Sounds like you want to do the job simply cause you have the part. but what of the labor, and then consider two years from now you end up HAVING TO doing it again cause your leak down test says you need a valve job, or a lifter fails. So are you going to put a head with 134K miles back on without doing the valves too? I say hold off on the extra work, you may never need to redo the head with its existing gasket. if eventual the gasket fails, or valves need work, or you need a new cam, or lifters, that is the time you put a new head gasket in.

thats my take on it.
 
Has it developed the typical head gasket oil leak on the passenger side yet? If it has replace it now, it will save you a lot of oily mess and you are already doing the hard part with the intake and exhaust. If it hasn't, hold off.. And with all due respect to black1990jeep, 136k, imo, is no where near needing a valve job, these aren't no 1985 sbc. When I lost my head gasket due to overheating because of exploded radiator at 220k I just pulled it off, (with intake and exhaust still attached,) cleaned it up and slapped it back together. Same bolts too. At 250k, driven a hard, stop and go 150 miles a day, still runs like a top. Sometimes you just need to get back on the road and have limited funds and time to do it.

Flush out the block the best you can when that water pump is off though. You would not believe how much crap settles in there!
 
Well, these jobs have a way of snowballing. Parts break, bolts/studs snap. It's good you're prepared.

Once the manifolds are off, check your compression. Also look into the ports to check the tops/stems of the valves.

Here's what mine looked like.

BF0tOGtl.jpg


If there are no signs of leaks, I'd leave the headgasket alone.
 
Yeah. as far as stuff i'd do. Change the fluids. drive it til it breaks.
these oil cast iron blocks and heads are pretty much invulnerable.
 
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