What was found
DURING CLIMB, PILOT NOTED RT OIL PRESS FLUTUATING SLIGHTLY & SLOWLY FALLING. ENGINE SHUTDOWN & RETURNED TO BASE. INVESTIGATION REVEALED A LEAKING OIL COOLER HOSE. LEAK POINT COVERED BY FIRESLEEVING. HOSE REMOVED & SLEEVING CUT OPEN REVEALING WIRE BRAID. EXTERNAL EXAMINATION DID NOT INDICATE ANY OBVIOUS VISIBLE DEFECT. FURTHER INVESTIGATION USING A FLEXIBLE LIGHT SOURCE REVEALED A FAILED INNER WALL MID-WAY IN THE HOSE AND ON THE INSIDE RADIUS OF THE HOSE BEND. THE HOSE MANF. DATE 01/04. PROBABLE CAUSE WAS INCORRECT HANDLING OR INSTALLATION OF HOSE AT SOME POINT WHICH RESULTED IN KINKING OF THE HOSE AND EVENTUAL FAILURE OF THE INNER WALL.