To our knowledge, we present the first experimental evidence of a “colloidal motor” behavior of a suspension. Previous attempts to observe such a phenomenon with ferrofluids under alternating magnetic fields have failed. Here, the viscosity decrease is obtained by making use of Quincke rotation: the spontaneous rotation of insulating particles suspended in a weakly conducting liquid when the system is submitted to a DC electric field. In such a case, particles rotate around any axis perpendicular to the applied field. Nevertheless, when a velocity gradient (simple shear rate) is applied along the E field direction, the particles rotation axes will be favored in the vorticity direction (the direction perpendicular to the suspension velocity and the velocity gradient). The collective movement of particles drives the surrounding liquid and then leads to a reduction of the apparent viscosity of the suspension. The decrease in apparent viscosity is sufficiently important for the suspension to display motor behavior.