In addition to what Jim said, I agree I would do a little more investigating before you go after the head gasket. Not that the gasket isn't a possibility, its just a lot of work to just jump into, and there are other checks you can do to narrow down the possibilities.

First look at your oil and coolant levels, and condition.
ò If you have leak between the cooling jacket and a combustion area you will be getting crap in your coolant, and like Jim said you will be over pressurizing the cooling system and puking it out the over flow.
ò If you have a leak between the cooling jacket and the oil system, you will have oil in the coolant and coolant in the oil. The coolant will get murky and dirty, and the oil will start to look like a chocolate milkshake, and the oil filler cap will get a real nasty build up on it that will be easy to see.
Next do a compression check.
ò If you are leaking combustion into the coolant you will lower compression on the ôbadö cylinder.
Next do a leak down check.
ò If you are leaking combustion into the coolant you will see bubbles in the coolant.
If after all of that you determine you are leaking between a combustion chamber and the cooling jacket, I would check the torque on all of the head bolts. If any of them are low, I would torque per the spec, and repeat the previous test, to see if there was any improvement.
If you still believe you have a leak between a combustion chamber and the cooling jacket, odds are it is most likely the head gasket, in which case, I would get a gasket kit for the top end of the engine and plan a weekend to do the work. The top end gasket set will have the head, valve cover, intake, exhaust gaskets, etc, valve guide seals, and all the little bits and pieces you donÆt really think of. While you have the head off, you might as well replace all the gaskets and seals you can. If your engine is high mileage, you might want to replace the water pump, hoses, thermostat, and flush the cooling system too. I agree you can do the work with the engine in the jeep too, its not too bad.

Sean