My 92 4.3 uses 9/16", my 88 Four uses 5/8", my Neighbors 93 uses a15mmAllen.
3/8"
It takes a 17mm Allen wrench to remove the fill plug.
It should be a 3/8" Allen wrench.
The size wrench to remove it should be 15mm.
13mm
What size line wrench for a 2005 freestar
13mm
15 millimeter
On mine it takes 14mm.
A 5/8" socket wrench.
My 92 has a 9/16 size plug My 1997 LeSabre has a 15mm drain plug.
14mm