What was found
LEFT PACK RUNNING OIL ODOR IN COCKPIT. ACP'D POWER RUN OF BOTH ENGINES, OPERATED PACKS TO ISOLATE SOURCE OF ODOR. FOUND ODOR PRESENT ONLY WHEN LEFT TRIM AIR SELECTED ON AND HEAT DEMANDED. CONDITION EXISTS REGARDLESS OF AIR SOURCE. ODOR NOT PRESENT WITH RIGHT PACK REGARDLESS OF AIR SOURCE. ODOR DISSIPATES WITH LEFT TRIM AIR DE-SELECTED. NEED FLT DECK AIR DISTRIBUTION MUFFLERS, ODOR ONLY OCCURS WHEN LT TRIM VALVE OPEN ON LT PACK. ODOR IS ONLY IN COCKPIT AREA, MUFFLER LOCATED FWD PIT LT SIDEWALL ACROSS FROM DOOR.