Help! Can't unscrew 2001 JGC 4.0L oil filler plug!

Aw...never mind. I just figured out DC's wacky design on this thing. I pried the top cover off and then unscrewed the remaining threaded section with pliers. Then pounded the thing back together with a mallet for reinstall.

This same exact thing happened years ago...but I forgot. Duh!

My 4.0's filler cap did that when I first got the Jeep (used). I found that the cap is made from two pieces of plastic that are snapped together.

The first few times that I changed the oil, I had the same problem as you. Expecting to have to buy a new cap, I twisted the cap so much that the top piece popped off (you could pry it off without much effort). Then, using a wide-bladed screwdriver, I pushed against the "ratchet fins" to back-off the actual (inner/lower) cap. Afterwards, I snapped the two pieces back together. As I said ths happened for the first few oil changes - then it just healed itself.

Jim '98 XJ