What was found
OIL ODOR IN THE COCKPIT AFTER DEPARTURE THAT DID NOT SUBSIDE. RETURNED TO DEPARTURE. R & R NR 1 & 2 WATER SEPARATOR COALESCER BAGS AS PRECAUTION TO REMOVE ANY RESIDUE THAT MIGHT CAUSE ODOR IN COCKPIT IAW AMM 21-51-16-3. AFTER REPLACEMENT, PERFORMED AN AIR COOLING SYS SERVICING. CLEANED AIR CON DUCTS IAW AMM 21-51-00-3, PERFORMED BOTH APU & ENG BLEED AIR SYS CLEANING IAW AMM 21-51-00-3. RAN APU IAW JRH, & PERFORMED ENGINE RUN IAW JRH CH 6. ALL INDICATIONS NORMAL. ACFT OK FOR SERVICE. APU INLET & COMPT INSP, NO OIL FOUND.