What was found
AT FLT LEVEL 320 LOWER AFT BODY OVERHEAT LIGHT ILLUMINATED, WENT TO QRH TURNED RIGHT PACK SWITCH OFF, LIGHT STILL ON. CLOSED NR 3 BLEED LIGHT STILL ON. CLOSED CARGO HEAT SWITCH LIGHT STILL ON. WHEN NR 3 THRUST LEVER RETARDED LIGHT WENT OUT. WING ANTI-ICE WAS NEVER USED. CABIN ALTITUDE STARTED CLIMBING ABOVE 10,000 FT WENT ON 02 DIVERTED INTO MDT. FOUND BOTTOM CLAMP ON NR 3 PURGE VALVE POSITIONED SO THAT THE CLAMP GAP WAS DIRECTED ONTO THE OVERHEAT LOOP. REPOSITIONED CLAMP AND RAN ENGINES AND PACKS AT VARIOUS POWER SETTING. NO DEFECTS M/M 26-14-000-5.