As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
APU ON AT GATE FOR 3 MIN. PUT BOTH PACKS ON NOTICED BLUE-OIL SMOKE IN COCKPIT & CABIN. REPLACED APU. STAT-O-SEALS FAILED IN THE DRIVEN COMPRESSOR MODULE. RUBBER WAS EXTRUDED AND TORN FROM BOLT HEAD AND SHAFT. NO LOOSE BOLTS NOTED. SEALING FUNCTION COMPROMISED ON BACKSHROUD INNER DIAMETER BOLT CIRCLE.