What was found
LARGE PLUME OF WHITE SMOKE FROM APU EXHAUST ON NORMAL SHUTDOWN. VERIFIED APU OIL AT A SERVICABLE QTY ON EICAS 5.7 WITH APU OFF. OPERATED APU FOR 30 MINS WITH NO LOAD. PERFORMED A NORMAL SHUTDOWN & STILL SAW WHITE SMOKE AFTER INTIAL SHUTDOWN. NO WHITE SMOKE DURING OPS. IAW AMM 49-11-00, 12-13-04, OPERATED APU AGAIN WITH NORMAL SHUTDOWN, LARGE PLUME OF SMOKE STILL PRESENT. SMOKE SMELLED OF OIL. REPLACED LUBE CLUSTER IAW FIM 49-10 TASK 836. REPLACING FUEL CLUSTER AS A PRECAUTION, DUE TO REMOVAL TO GET ACCESS TO LUBE CLUSTER. R & R APU FUEL & LUBE CLUSTERS IAW AMM 49-31-31, 49-27-27. LEAK CHKD GOOD. COMPLETED APU FUEL CLUSTER & LUBE CLUSTER INSTALLATION TEST IAW AMM 49-31-31, 49-27-27. OPS CHKD GOOD.