I have a 91 with 202K miles on the 4.0 engine.
I had the oil change, WIX filter every 4-5K miles and I watch my oil levels. I usually add about a Qt in between changes. Drove to the beach 3 hours away this weekend but did NOT check before I left. Before heading home I checked and needed to put in 3 Qts. and a little Antifreeze. Antifreeze was not full of oil nor was there any sludgy pudding residue on dip stick etc.
I haven't run the A/C much this year but did run it while down at the shore and some on the way back. Return trip took 4 1/2 hours instead of the normal 3 hr. drive because of traffic.
Long story short is I was a Qt. low after getting back home, only 200 or so miles.

There is no physical evidence of any oil leak, no drip in the driveway and seemingly no more residue underneath than normal.
I have no idea where it is all going or what is actually leaking.
I had a head gasket done about 4K miles ago but don't think it was done well so I am thinking about redoing that but otherwise at a loss.

One other thing of note, when I add oil through the valve cover I can "hear" the oil trickle through to a lower part of the engine. Is that normal?

 

Trickling sound is normal. At least I hope it is or I'm in trouble haha.

You're either leaking somewhere or burning oil. Ever notice any blue smoke in your mirror?

 

^^^^^^^^^^^^^
Ha-Ha, took me longer to think.......
As far as the oil it is either:
1. Burning it
2. dumping it on the ground.
Not many other options.

 

X3

1. Leaking
2. Burning

 

Oil gnomes. They sneak in at night and pump your oil out through the dispstick.

 

I've heard of siphoning gas, never siphoning oil. That's a new one

 

Hmm... Just like I see no evidence of where the water's getting INTO my Jeep.

Jeeps are masters of burying evidence, huh?

 

Blue smoke, no; white smoke, yes but only when idling for more than a few minutes
I have zero puddles and no drips that are visible.

 

That's a bad sign. What's your temp gauge like when there's white smoke?

 

temps are all normal 190-210 and then if it reaches 210 drops right away

 

White smoke isn't good... Do a compression test

 

"I have zero puddles and no drips that are visible."

Park it on a sheet of cardboard let it idle for a while then sit overnight, check in the a.m. If you don't find a lake of oil, it's burning it.