During fatigue testing of prototype austempered ductile iron crankshafts, cracks formed along crankpin fillets. These cracks were not detected by the conventional magnetic particle method but were readily imaged by a modified version of the gel electrode technique. The crankshaft was coated with a thin (∼0.5 μm) polymer film, either prior to, or after, the fatigue test. When the surface was subsequently inspected with a gel electrode probe, an impressed current from the probe flowed preferentially to the fatigue sites. Information is displayed in two formats: (i) qualitatively as a direct image of the fatigue sites, and (ii) quantitatively as the spatial distribution of charge flow to the surface. Both the primary fatigue cracks and a distribution of secondary sites of less severe fatigue damage were detected. The cracks formed near the edges of a fillet while the root of a fillet developed primarily secondary fatigue damage.