What was found
DUE TO HISTORY OF APU HOC, AND CONSULTATION WITH TOMC, FILL APU OIL LEVEL TO FULL, RAN APU FOR TWO HOURS WITH APU BLEED OFF. APU BURNED 1 QT OF OIL. NO LEAKS FROM LUBE DRAINS. DID FIND OIL LEAKING FROM SURGE VALVE COUPLING DUCT AT AFT DUCT MOUNT POINT. APU FAILING INTERNALLY. APU HAS INTERNAL FAILURE. FOUND APU TO BE BURNING 1 QT EVERY TWO HOURS WITH NO EXTERNAL LEAKS OR LEAKAGE FROM LUBE DRAINS. FOUND OIL LEAKING OUT OF SURGE VALVE DUCT COUPLER AT AFT MOUNT WHERE AIR GOES INTO EXHAUST STREAM. SLIGHT SMELL OF OIL IN CABIN AND OIL SMELL IN EXHAUST. REPLACED APU PER AMM, OPS AND LEAK CHECK NORMAL.