Head gasket leak on 2001 4.0

01saharatj

01saharatj

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Noticed a pool of water under Jeep but not under radiator.. seems head gasket is leaking on passenger side of block. Does stop leak work? Also if I replace head gasket before it over heats can I just swap out gasket and reinstall head without machine shop work being done to head?
 
I just did my neighbor's 04 4.0 WJ. Small slit in the heater hose. Kids overheated it. Pulled the thermostat, filled it with distilled water...fan tail of water between the block and heads when it got warm. I love it when a problem and solution is that obvious.

Took more time to take apart the double cat manifold than it did to pull the head, check a ton with a good straight edge, clean the absolute crap out of everything and put on a new head gasket.

I used copper gasket spray JIC which is a deviation from the FSM. New head bolts and replaced two push rods cause they looked wiggly.

Runs great. Daily driver for the last couple months no issues.

4.0s are like AK-47s. You can do everything wrong and they just work.

That being said...it might not be a head gasket. Passenger side has heater hoses. Freeze plugs. Could be water condisation from the AC or a bad heater core leaking through that drain.

Lots of things to rule out.

I'd do a combustion gas test...you can rent/borrow one from most auto parts stores...and report back. That'll tell you if combustion gas is making it into the antifreeze.

-Mac
 
Running your A/C? Could just be condensation from the drain. Dunno the temp where you are.

As far as stop leak? Don't even think about it. The leg humpers will be here soon to tell you why. And they will tell you about tupy heads.
 
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01saharatj said:
Noticed a pool of water under Jeep but not under radiator.. seems head gasket is leaking on passenger side of block. Does stop leak work? Also if I replace head gasket before it over heats can I just swap out gasket and reinstall head without machine shop work being done to head?
Click to expand...

No stop leak.

Get head checked for flatness before reassembly and be sure it is the updated version if applicable.

Make sure you know where the coolant is coming from before taking it apart.
 
P man said:
01 would fall into the range that experienced cylinder Head issues. Please verify which head you have and think about swapping to the updated version
Click to expand...

Didn’t know there was an issue with these heads ? Whats do I look for?
 
have an ‘01 as well, oil was seeping slowly from the backside of the engine. A little chocolate milk in the radiator cap when checked. If you’re going to replace the gasket, I’d take it to a machine shop to see if it’s cracked, that may be your issue. It was with mine.
 
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TU-PY or not TU-PY, that is the question.

The answer...

Get an aftermarket head unless you find a good deal on a TUPY head.

Remove the cap and look down into the head.

This is what you're looking for.

TUPY head appeared in late 2001/early 2002 I believe.

img_3207-jpg.jpg
 
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tr21triton said:
NON-TUPY = not the TUPY head (AKA before the TUPY MOD) (AKA the fix for the 0331 heads that were cracking ) !!!! Do we need to explain further ?
Click to expand...

Incase both of you missed it, I’ll explain further, I was agreeing with you. I stated yes, tupy 0331 is the one you want. What did you not understand? Doesn’t matter, don’t care.
Original post, I would say to be safe then yes you probably need an updated head. 🍻 And good luck

IMG_2597.png
 
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