What was found
LAX - LEFT ENGINE LOOP-A LIGHT FOLLOWED BY LEFT ENGINE FIRE WARNING DURING CLIMBOUT AT APPROXIMATELY 6000 FEET. THROTTLES TO IDLE AND LIGHTS AND WARNING WENT OUT. LEFT EXHAUST GAS TEMPERATURE AT TAKEOFF IN YELLOW ZONE. RIGHT ENGINE EXHAUST GAS TEMPERATURE NORMAL. CONTINUED OPERATION AT IDLE FOR 20 MINUTES. LANDED LAX WITHOUT INCIDENT. FOUND 13TH STAGE MANIFOLD INNER CASE BLOWN APART. CHANGED LEFT ENGINE. SYSTEM GROUND CHECKED NORMAL OPERATION.