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You guys ever seen this? Pin holes in head

GreatOdin'sRaven

NAXJA Forum User
Location
Las Vegas, NV
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So I had overheating problems and Jeep was leaking bad in the back near the firewall.

Just took off the head to get to the gasket and saw where the water was coming from. Shooting out of these holes onto my firewall like a hose.

Is this a common thing?


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:rolleyes:

Yup and yup. What they said.
 
Like everyone else said that's your freezeplugs failing, and yeah it does happen. They're not hard to replace except for the whole Step 1: remove manifolds/engine part :shiver:. Just tap-rotate them out with a screwdriver and a hammer at 3 or 9 o'clock on each one. Please, for the love of god, replace them with a good-quality brass set and don't make the mistake of using cheap ones matched at the parts store... I had to do mine twice after one of those cheap ones popped out on the freeway, instantly dumping all my coolant and leaving me to catch a flatbed tow home.

The only redeeming part of that experience was that it happened on the freeway, instead of 25 miles into the desert where I was heading that day. When I tore it apart and fixed it I used the best brass kit I could find and JB-welded them all in :laugh:
 
Good time to replace the plugs in the block...
 
Guys, awesome.

I've never known about freeze plugs. Going to replace it soon with brass💪.

Some of you mentioned freeze "plugs" (plural)

Are there multiple plugs or just one?


Also bonus question:

Since my engine is all torn apart is this a good time to get anything else done/replaced?


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Since my engine is all torn apart is this a good time to get anything else done/replaced?
How many miles on the engine, did you happen to do a compression test before you took the head off?
 
Thanks! I guess it would make sense to change ALL of them now and save my self the headache in the future.
Yep! If one is already toast, the rest are close behind.

In this picture that Sidewinder posted, the expansion plug in the bottom right corner is the Cam Plug, don't mess with that. If it looks rusty, clean it up and paint.


135k.

Did not do a compression test.
Flip the head upside down and support it so the surface that mates to the block stays level. Pour Mineral Spirits into each combustion chamber and watch the intake/exhaust runners. If the Mineral Spirits leak through, have an automotive machine shop look it over.
 
Yep! If one is already toast, the rest are close behind.

In this picture that Sidewinder posted, the expansion plug in the bottom right corner is the Cam Plug, don't mess with that. If it looks rusty, clean it up and paint.



Flip the head upside down and support it so the surface that mates to the block stays level. Pour Mineral Spirits into each combustion chamber and watch the intake/exhaust runners. If the Mineral Spirits leak through, have an automotive machine shop look it over.

I guess you could do it that way, but if the head is off I just drop it off at the machine shop and let them go through it. From what I have seen 4.0's benefit from head work every 160,000 miles and you're pretty close to that.
 
I guess you could do it that way, but if the head is off I just drop it off at the machine shop and let them go through it. From what I have seen 4.0's benefit from head work every 160,000 miles and you're pretty close to that.





Was planning on dropping it off at a local machine shop for peace of mind. The Jeep did ovwrheat a couple times as I was figuring out what the hell was going on.

I just need to find a pack of brass freeze plug now.

Also gonna paint a few items now that everything it out of my way.

Thanks so much guys. Love this forum, always super helpful


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I guess you could do it that way, but if the head is off I just drop it off at the machine shop and let them go through it. From what I have seen 4.0's benefit from head work every 160,000 miles and you're pretty close to that.

Since he has to pull the engine to work on the plug on the back, what is the service life on the timing chain?

I would at least replace the gaskets on the bottom end, and the rear main seal.
 
Doing the oil pan, RMS, and oil filter o-rings would be a good idea.

No idea on the service life of the 4.0 timing chain.

Really depends on the maintenance of the vehicle.

When I did lower end gasket work on my 97 when I first got it at 184K it was at about the halfway wear point, and when I did the same lower end seal work on my 01 at around 330K it was also at about the halfway wear point.
 
Where does someone find "Quality" Brass freeze out plugs?

I'm in the same boat -- engine swap -- although the replacement only has 27,000 on it I was thinking of changing out the freeze out plugs
 
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