What was found
MIA - FLT 741 - EN ROUTE PHL TO MIA. ON TAXI-OUT, THE FLIGHT CREW NOTICED THAT THE LEFT RECIRCULATION FAN WAS NOISY. THE FAN WAS TURNED OFF AND THE FLIGHT PROCEEDED. DURING THE FLIGHT, THE FLIGHT CREW NOTICED AN OILY ODOR COMING FROM THE COCKPIT GASPER VENT. THE CREW SHUT-OFF THE RIGHT RECIRCULATION FAN, AND THE ODOR DISSIPATED. THE FLIGHT CONTINUED WITHOUT FURTHER INCIDENT. MAINTENANCE PLACED AIRCRAFT ON MEL. MAINTENANCE REPLACED THE LEFT RECIRCULATION FAN. OPERATIONALLY CHECKS OK.