What was found
DISTINCTIVE OIL ODOR ISOLATED TO COCKPIT PACK AIRFLOW FROM COCKPIT PACK VERY WEAK. RAN APU, NO ODOR NOTED FROM EITHER PACK AND AIRFLOW WAS NORMAL FROM BOTH PACKS. VERIFIED STRONG FLOW AT BOTH ACM INTAKES. STARTED ENGINES AND TURNED OFF APU OIL. AGAIN AIRFLOW WAS STRONG IN BOTH COCKPIT AND CABIN WITH NO OIL ODOR NOTED AND STRONG FLOW AT ACM INTAKES. PER THE CUSTOMER REQUEST, INSPECTED WATER SEPARATOR SOCK AND FOUND NOT TO HAVE ANY KNAP ON EITHER SOCK. REMOVED AND REPLACED BOTH SOCKS AS REQUIRED IAW 750 M/M CH 21-51-00. PERFORMED GROUND RUN. OPS/LEAK CHECK GOOD.