What was found
ON 5/25/04, WHILE RETURNING, THE PILOT NOTICED AN INTERMITTENT LOSS IN MANIFOLD PRESSURE ON THE RT ENGINE. A GRADUAL LOSS OF OIL PRESSURE BEGAN TO DEVELOP SO THE PILOT SHUT DOWN THE ENGINE AS A PRECAUTIONARY MEASURE AND CONTINUED ON COURSE TO FAI. AIRPLANE LANDED WITHOUT PROBLEMS. MAINT THOROUGHLY INSPECTED THE ENGINE AND FOUND NO MAJOR DEFECTS. OIL WAS ADDED TO BRING THE LEVEL FROM FOUR TO ELEVEN QUARTS AND OPERATIONAL CHECK FLIGHT WAS CONDUCTED TO SEE IF THE PROBLEM PERSISTED. AFTER THE CHECK FLIGHT, THE OIL FILTER WAS REINSPECTED AND NO DEFECTS WERE NOTED. AIRCRAFT RETURNED TO SERVICE.