What was found
RIGHT ENGINE SHUT DOWN DURING TAXI DUE TO HIGH ENGINE OIL TEMP. FUEL OIL HEAT EXCHANGER AND VALVE WERE REPLACED AND PROBLEM SEEMED FIXED. NO DISCREPANCIES FOR NEARLY FOUR WEEKS. THEN LOW OIL QUANTITY AND INCREASING OIL TEMPERATURE HIT AGAIN. NR 5 BEARING PRESSURE AND SCAVENGE TUBES REPLACED WITH NO EFFECT. ROOT CAUSE FINALLY FOUND AS THE RETAINING STUDS ON THE GEARBOX SCAVENGE PUMP FAILED AND ONE HELICOIL STRIPPED. COA WRITTEN TO INCORPORATE FIX. COA ACCOMPLISHED ON THIS ENGINE AND NO FURTHER DISCREPANCIES FOUND.