What was found
ON FLIGHT 4173 THE CREW REPORTED AN OILY SMELL IN COCKPIT AFTER TAKEOFF. BOTH PACKS OPERATING ALT TO-1 THRUST. THE AIRCRAFT WAS REMOVED FROM SERVICE. REMOVED AND REPLACED THE GEN NR 4 GARLOCK SEAL IAW RR MM 72-63-10. THE OPERATIONAL CHECK WAS GOOD AND THE LEAK CHECK WAS GOOD. A FUNCTIONAL CHECK FLIGHT WAS PERFORMED AND FOUND TO BE SATISFACTORY. GROUND RAN BOTH ENGINES AT IDLE AND MAX TAKEOFF SETTINGS IAW ROLLS ROYCE MM 72-00-00. NO NOTICEABLE OIL ODOR IN EITHER COCKPIT OR CABIN. THE OPERATIONAL CHECK WAS GOOD. THE AIRCRAFT WAS RETURNED TO SERVICE.