What was found
DISTINCT "OILY" SMELL IN COCKPIT, SEEMINGLY FROM GASPERS. NO HAZE OR SMOKE NOTED. CABIN CREW DID NOT REPORT ODOR. C/W FIM TASK 71-00-00-810-817 AND SL DH8-400-SL-21-012A TO PURGE THE ECS. INSPECTED THE NR1 AND NR2 ENGINES FOR LEAKS, NONE NOTED. INSPECTED NR 1 AND NR 2 ENGINE OIL LEVEL, CHECKS GOOD. INSPECTED NR 1 AND NR 2 ENGINE COMPRESSOR INLET BLADES FOR OIL CONTIMINATION, NONE NOTED. INTERROGATED CDS FOR FAULTS "L BLEED DIFF PRESS "1502" AND "3B01 DIST DAMPER" FAULTS. CLEARED FAULTS. GROUND RAN ACFT, NO FAULTS NOTED. NO ODORS NOTED FROM BLEEDS. OPS TESTS GOOD. RETURNED TO SERVICE. NO PARTS REPLACED.