What was found
ON CLIMBOUT THRU APPROXIMATELY 8000, RECEIVED A L JET OVHT FAIL CAUTION MESSAGE AND THEN A L JETPIPE OVHT WARNING MESSAGE. COMPLIED WITH QRC AND QRH AND MESSAGE CLEARED. RETURNED TO SFO. (FLIGHT 5953 - FILED CLOSED)PERFORMED INSP OF LT ENG ZONE B SENSING ELEMENTS, CONNECTIONS, AND WIRING. NO DISCREPANCIES FOUND. PERFORMED INSP OF10TH AND 14TH STAGE BLEED AIR DUCTS AND CONNECTIONS AT PYLON AREA. NO DISCREPANCIES FOUND. PERFORMED LT ENG RUN AND LEAK CHECK OF ASSOCIATED BLEED AIR DUCTS. NO LEAKS FOUND. REPLACED FIRE DETECTION CIRCUIT CARD A2. REF AMM 26-10-02. OPS CHECK GOOD.