What was found
DURING CLIMB OUT, LEFT ENGINE OIL PRESSURE BEGAN TO FLUCTUATE. AFTER MOMENTS OF FLUCTUATION, OIL PRESSURE DROPPED THROUGH CAUTION AND ENGINE WAS MANUALLY SHUTDOWN. DURING INSPECTION FOUND ONE OF THE OIL PRESSURE PUMP TRANSFER TUBE O-RINGS FAILED. REPLACED O-RINGS AND INSPECTED ENGINE. NO FURTHER DEFECTS NOTED. OPS AND LEAK CHECK GOOD. PROBABLE CAUSE IS AGE AND USE OF O-RING. ENGINE AND OIL PUMP ARE 180.3 HOURS FROM OVERHAUL. NO MAINTENANCE ON COMPONENT NOTED SINCE NEW. TO PREVENT RECURRENCE EVALUATE IF THERE IS A NEED OF RESEAL BETWEEN OVERHAUL.