What was found
FUMES IN COCKPIT AND CABIN WHILE SMOKE REPORTED BY OTHER AIRCRAFT FROM ENG NR 1 ON GROUND AFTER 2.5 HOUR TAXI GATE RETURN. REMOVED AND REPLACED LT AND RT WATER SEPARATOR/COALESCER BAGS REFERENCE AMM 21-20. REPLACED NR 1 ENGINE. PERFORMED NO GO ODI PREVENTION ATA 2172 WORK CARD 2120-2367, 2120-2368, 7100-2619. FOUND NO EVIDENCE OF TURBO OIL IN IN ANY PNEUMATIC DUCTS. DUCT BURNOUT PERFORMED RAN ENGINES & A/C PACKS NO FUMES PRESENT A/C OK FOR SERVICE.