How much oil does my Mitsubishi engine hold? Engine Model Low to High S6B3 13.7 - 18.5 gal S6A3 18.5 - 26.4 gal S6R 29.1 - 37.0 gal S12A2 24.3 - 31.7 gal S12R 41.7 - 52.8 gal S16R 51.5 - 68.7 gal