A bearing isolator seal comprising: a rotor surrounding and rotationally fixed to a rotatable shaft, said rotatable shaft being configured to rotate about a rotation axis; an O-ring retention groove; a shut off O-ring expandably located within the O-ring retention groove and configured to rotate with the rotor; a stator surrounding the rotatable shaft and configured to remain stationary when the rotor is rotating; a stator extension, the stator extension being an extension of the stator that is overlapped by the shut off O-ring, so that the shut off O-ring makes a seal with the stator extension when the rotor is at rest, but is expanded away from the stator extension by centripetal force when the rotor is rotating; and a tapered section included in the stator extension, the tapered section being a section of the stator extension that is at least partly overlapped by the shut off O-ring when the rotor is in the neutral position, characterized in that the O-ring retention groove is formed in an inward-facing surface of the rotor, the shut off O-ring has an inner diameter that extends inwardly beyond the inward facing surface of the rotor, the rotor and stator are configured to allow the rotor to shift axially relative to the stator from a neutral, axially aligned position when at rest to an axially misaligned position further removed from the stator while rotating, the tapered section has a surface that is tapered such that a diameter of the stator extension directly beneath the O-ring is reduced when the rotor is in the axially misaligned position, as compared to when the O-ring is in the neutral position, the bearing isolator seal further comprising a horizontal section of the stator that extends under the shut off O-ring beyond the tapered section, the horizontal section being configured to form a line-on-line fit with the shut off O-ring when the rotor moves beyond the maximum axial displacement. a rotor surrounding and rotationally fixed to a rotatable shaft, said rotatable shaft being configured to rotate about a rotation axis; an O-ring retention groove; a shut off O-ring expandably located within the O-ring retention groove and configured to rotate with the rotor; a stator surrounding the rotatable shaft and configured to remain stationary when the rotor is rotating; a stator extension, the stator extension being an extension of the stator that is overlapped by the shut off O-ring, so that the shut off O-ring makes a seal with the stator extension when the rotor is at rest, but is expanded away from the stator extension by centripetal force when the rotor is rotating; and a tapered section included in the stator extension, the tapered section being a section of the stator extension that is at least partly overlapped by the shut off O-ring when the rotor is in the neutral position, characterized in that the O-ring retention groove is formed in an inward-facing surface of the rotor, the shut off O-ring has an inner diameter that extends inwardly beyond the inward facing surface of the rotor, the rotor and stator are configured to allow the rotor to shift axially relative to the stator from a neutral, axially aligned position when at rest to an axially misaligned position further removed from the stator while rotating, the tapered section has a surface that is tapered such that a diameter of the stator extension directly beneath the O-ring is reduced when the rotor is in the axially misaligned position, as compared to when the O-ring is in the neutral position, the bearing isolator seal further comprising a horizontal section of the stator that extends under the shut off O-ring beyond the tapered section, the horizontal section being configured to form a line-on-line fit with the shut off O-ring when the rotor moves beyond the maximum axial displacement.