What was found
DURING CRUISE FLT AT FL300 250KTS, HAD WHITE SMOKE OMITTING FROM TOP OF GLARESHIELD. REF QRH SMOKE FUMES OF ELECT, AIR COND OR UNKNOWN REASONS, DECLARED EMERG WITH VHHH AND EXPEDITED TO A LANDING AT VHHH. SMOKE DISSIPATED BY LANDING CREW VERBAL NOT ELECT BURN, JUST SMELL OILY AND ACFT ALL SYSTEM WORK NORM. INSP AV COMPT & ALL DU'S INST PNL AREA, ALL WIRING NO DISCREPANCY. INSP ALL 3 PACK'S COALESCER BAG FOUND NR 3 HAS SLIGHT OILY SMELL. PERF AIR COND ODOR DIST DUCT CLEANING PER MM 21-53-00-7.RR ALL 3 COALESCER BAG'S PER 21-54-05-2.C/W THE MTSI INSP ALL 3 ENG 8TH STAGE CHECK VALVE & APU LBV DUCTING NO WET SIGN PER 36-11-01-4 & 36- 16-02. PRECAUTIONARY DEF NR 3 PACK PER MEL 21-51-01-A. ACFT OK FOR SERVICE.