[WFBowen]

eki:
If your cap's been missing, chances are the inside of the fan has lots of "patina" on it. If you can't find the mark, might be a good idea to yank the fan (may as well put on a new belt while you're there since most of the stuff comes off for replacement) then clean it up & find the mark. Once you've found it, you can clean up & paint the outer (car rear) side & establish new, accurate marks that you're sure of.
Good luck,
Bill.