What was found
IN CRUISE FLIGHT AT FL 270, LOWER AFT BODY OVERHEAT LIGHT CAME ON. OPERATING ENGINES 2 AND 3 BLEEDS AT THE TIME WITH BOTH PACKS. OVERHEAT LIGHT WENT OUT AFTER FOLLOWING ABNORMAL EMERGENCY RED TABS CHECKLIST. OVERHEAT LIGHT WENT OUT AFTER SHUTTING OFF NR 2 ENGINE BLEED, (1 MINUTE). CHECKED AFT BODY HEAT AREA FOUND AIR LEAK IN KEEL BEAM AREA. TIGHTENED CLAMP RE-RAN ENGINES, OPERATIONAL CHECK GOOD.