What was found
AT FL 340, WE NOTICED A GREASE OILY SMELL COMING FROM THE PACKS. WE HAD JUST SELECTED A WARMER TEMPERATURE. FUMES VERY NOTICEABLE SMELL CEASED AFTER SETTING FLT DECK TEMP CONTROL TO PREVIOUS COOLER SETTING RAN PACKS SEPARATELY ON APU AIR AND AT DIFFERENT TEMP SETTINGS WITH NO DEFECTS NOTED. INSPECTED BOTH PACK BAYS WITH NO OIL RESIDUE NOTED. ALSO NOTED THAT THE ACM'S HAVE AIR BEARINGS. FURTHER T/S REQUIRED. PERFORMED AIR CONDITIONING SMOKE/FUME CONTAMINATION MAINT PRACTICES. REF AMM 21-00-21. RAN BOTH ENGINES AND PACKS AT MULTIPLE POWER AND TEMP SETTINGS. ISOLATING EACH PACK AND BLEED SOURCE. NO SMOKE OR FUMES NOTED. OK FOR SERVICE.