Originally Posted by Mopargearhead
Do you know if the head has ever been off the Jeep? If it has and the old head bolts were used that would be the cause of the leak. The head bolts on the 4.0L are one time use. If head work is done and the old bolts are used the head will literally lift off the block slightly and spit out oil. I would do as suggested and clean the engine very well and recheck.
While the head bolts are one time use (TTY bolts), many people reuse them without any ill effects (not that I recommend reusing them however.)
To say that the head lifts up from the block from reusing head bolts is just plain dumb. If this were the case, you would be spewing coolant, losing compression, ect. It would be a mess. However it is possible to blow a head gasket around an oil passage close to the edge of the block allowing oil to seep out. I'd look at the valve cover and distributor shaft seal before assuming it's the head gasket though.