A Line Mechanic reports he taxied an A320 to the gate and signed-off a post taxi walk-around accomplished by another Mechanic. He was later informed that an outbound First Officer had found a flat tip screw driver at the 6:00 o'clock position on the #1 engine right-hand fan exit strut; during his walk-around.

Narrative

After completing a #3 Service Check on an A320 aircraft; by doing the fuselage; tail and wheel well walk- around; signed for completion of #3 Service. Performed pre-taxi walk-around prior to aircraft delivery to gate for outbound flight. During walk-around; I did visually inspect #1 engine inlet and exhaust prior to boarding aircraft for delivery taxi to gate as a right seat taxi Mechanic.After delivery to gate; [we] de-boarded and while my left seat driver performed the post taxi walk-around at gate; I signed-off the pre-departure and aircraft Logbook Release. We departed the gate and returned back to company Maintenance Base. Shortly [thereafter we] received a call from the gate to return to assist in retrieving a tool (flat tip screwdriver) found by the outbound crew copilot during his pre-departure walk-around. The tool was located at the 6:00 o'clock position; right-hand side of the fan exit strut; at the intersection between the fan case and right-hand reverser. As viewed from front of engine; [screw driver was] behind fan blades and the fan exit guide vanes. Mechanics on gate opened right-hand reverser cowl; retrieved tool; inspected area; found minor crack and scratches on rubber seal at 6:00 o'clock position on the fan exit strut. Deferred the item and aircraft released for departure.