What kind of car do you have? Four cylinder or six cylinder?

For the four banger, you should have a 24mm or 25mm (whatever the closet to 1" is) size head on the drain plug. Unless you've got an oil temperature sender (you'd see wires coming from the drain plug).. and I believe that's a 22mm head.

And as everyone else pointed out, check/replace the copper washer. I don't bother with oil filters at the dealer ($10), instead I go for Mann filters ($3 or so at FCP Groton). However, I don't have any trouble getting a few of the washers from the dealer for free anyways. It's worth a shot, otherwise you can get them for cheap online if you must.

- alex

'85 244 Turbo
'84 245 Turbo