I agree with Carl. The Viton "o" rings are pretty much impervious to most
common oils and common industrial chemicals. The extra cost will be repaid
in reliability.

Yes, until you need to make a "special" by cutting out a section and
re-joining it. Cyanoacrylate (super-glue) works surprisingly well with
natural or nitrile rubber, but it won't work with viton (or silicone).