What was found
ON CLIMBOUT WITH AIRCRAFT CLEAN AND CLIMB POWER SET AT APPROXIMATELY 7,000 FEET THE ENGINE NR 3 STRUT OVERHEAT LIGHT ILLUMINATED. COMPLIED WITH RED TAB PROCEDURE AND LIGHT WENT OUT AND STAYED OUT FOR REMAINING 30 MINUTE OF FLIGHT. FOUND 6TH STAGE DUCT LEAKING AT CLAMP DOWNSTREAM OF CHECK VALVE. REMOVED AND REPLACED CLAMP, OPERATIONAL AND LEAK CHECK GOOD.