What was found
L 14TH BLEED AIR WARNING FREQUENTLY CLIMBING THRU 20,000FT ONCE EVERY 3 SECONDS, C/W QRH BROUGHT ENG TO IDLE. MSG CONTINUED 1 EVERY MINUTE. STOPPED WHEN ENG SHUT DOWMN ON GROUND. (BK 4) SNYOPTIC SHOWED RED BETWEEN 14TH SATGE SOC, MSOV AND COWL SOV. ALSO RECEIVED BLEED AIR DUCT AURAL WARNING. ***AIRCRAFT REMOVED FROM SERVICE*** PERFORMED LH ENGINE 14TH STAGE BLEED AIR LEAK TEST WITH ENGINES BLEED AIR IAW AMM 36-12-00 FOUND LH 14TH SOV AND LH AICE CLAMPS LOOSE. RE TIGHTENED LOOSE CLAMPS IAW AWAC SUP 10-008, NO LEAKS NOTED AT THE TIME. ALSO PERFORMED LH BLEED AIR LEAK OPERATIONAL CHECK IAW AMM 36-21-10, OPS CHECK GOOD.