The thing screwed into the side of my oil pan, that I assume to be a level sensor, is leaking oil out.

Do you think it will require replacing or is there some kind of gasket/seal that can be tightened/renewed?

There is a washer(seal) for that . It is p/n E9DZ-6C626-B and it has a list of 2.81 and LVC cost is $2.11

Max Zuckerberg
Parts Specialist
Five Star Ford
7100 east Mc Dowell Road
Scottsdale AZ 85257
Direct 1-800-866-1520 ext 236
Fax 1-480-949-8478
parts@fivestarford.com