What was found
DURING OIL CHECK FOR W/O 342506 FOUND # 2 ENG OIL CAP MISSING REMOVED FROM SERVICE. OPENED #2 ENG FAN COWLS & THRUST REVERSERS IAW E715 AMM 71-11-00-910-801A & 78-30-01-910-801-A INSPECTED SURROUNDING AREA, NO DAMAGE NOTED & CAP NOT FOUND. CLOSED FAN COWLS & REVERSERS IAW AMM 71-11-00-910-802A & 78-30-01-910-81-A. ALSO PERFORMED GVI OF UNDERWING & FLAPS WITH NO DEFECTS FOUND. FOUND WHAT APPEARS TO BE SCRATCH ON #2 O/B AFT CORE COWL WITH PAINT TRANSFER APPROX 22 INCHES IN LENGTH WITH NO MEASURABLE DEPTH. DEFERRED. INSTALLED NEW OIL CAP ASSY. IAW MCN E790007-01 STEP 2A & 3C&D, A/C OK FOR SERVICE.