A method includes initiating a test of a servo gauge by causing the servo gauge to attempt to move a displacer of the servo gauge, where the servo gauge uses a drum to move the displacer in a tank. The method also includes measuring a torque associated with the drum during or after the attempt to move the displacer and identifying a mechanical problem with the servo gauge based on the measured torque. For example, a stuck displacer can be identified when the measured torque exceeds an upper expected value. A lost displacer or a stuck drum can be identified when the measured torque is below a lower expected value.