What was found
AFT LEFT SMOKE DETECTOR ALARMED CLIMBING THROUGH 9000FT. IMMEDIATELY SMELLED SMOKE IN COCKPIT APPROX. 30 SEC -1MIN. SMOKE ODOR CLEARED AND ALARM STOPPED. F/A'S INSPECTED LAV BIN AND SMOKE BUT DID NOT EVER SEE SMOKE OR FIRE. INSPECTED APU INLET FOR CONTAMINATION. FOUND TO BE CLEAN AND DRY. CHECK DOWNSTREAM DUCTS OF BOTH ACM'S & ANTI ICE VALVES. NO OIL FOUND. CLEAN AND DRY. ACCOMPLISHED OPERATION OF RECIRCULATION FAN, OPS CHECKED NORMAL. OPENED BOTH ENG UPPER AND LOWER COWLS FOR INSPECTION IAW 72-00-00-280-801C3 & 801C1. PERFORMED BORRSCOPE INSPECTION BOTH ENGINES LPC AND HPC. FOUND NO EVEIDENCE OF OIL LEAKS. ALSO INSPECTED BOTH ENGINES SADDLE DUCTS, NO DEFECTS NOTED. REMOVED AND REPLACED BOTH LT & RT WATER SEPARATOR COALESER BAGS IAW AMM 21-20-02-2. COMPLETED PNEU SMOKE /ODOR TROUBLESHOOTING IAW CARD 2120-2367. LEFT ENGINE REPLACED. PNEUMATIC SYS DUCT BURNOUT IAW CARD 7100-2619. NO ABNORMALITIES NOTED. ACFT OK FOR CONTINUED SERVICE.