What was found
(CAN) ON CLIMB OUT THE ENG OIL PRESS WARNING LIGHT ILLUMINATED & THE CREW ELECTED TO RETURN. THE ACFT LANDED WITHOUT FURTHER INCIDENT. THE CREW PERFORMED A VISUAL INSPECTION OF THE ENG & FOUND EVIDENCE OF OIL LEAK. INSPECTED THE ENG, REPLACED THE PROPELLER CONTROL UNIT & FLANGE O RINGS. PERFORMED A LEAK CHECK & RELEASED THE ACFT BACK INTO SERVICE. FOLLOWING THE NEXT FLIGHT, OIL WAS AGAIN NOTICED IN THE VICINITY OF THE PCU. THE NR 1 PCU WAS REPLACED. OPERATIONAL & LEAK TEST COMPLETED BEFORE RELEASING THE ACFT.