13 mm is the exact size but 1/2 " will do
I have the 4 volume factory service book set issued by Chrysler for this car...13 mm and torque to 30 ft. lbs. The drain plug even says "Metric" on the head of it. All car mfrs converted to MM in the 1980's for all fasteners...like lug nut are now 19mm and so on.
you should never use a power gun to remove a oil plug ,you could strip the plug or worse the oil pan. i'm talking about the treads.
If you've got a cheap wrench, a 1/2" will fit on a 13mm head. Try it with a Snap-On wrench, and it won't work. If you want to strip off a head, start with a cheap wrench! (P.S. I use Snap-On at work, because they provide our tools. At home? Craftsman!) If you are REALLY concerned about stripping the head off, use a 6-point socket and ratchet!
I can tell you they didn't switch for everything, my 99 and 92 Dakotas, 98-99 Cherokees and 95 Wrangler all use a random assortment of metric and standard size fasteners.
