What was found
(CAN) DURING SCHEDULED OIL CHANGE, THE NR 4 CYLINDER ROCKER COVER WAS FOUND LEAKING. UPON REMOVAL THE C-CLIP WHICH HOLDS THE HYD PISTON IN ON THE LIFTER WAS FOUND NEAR ROCKER. PUSH ROD AND TUBE SHOWED SMALL AMOUNT OF DAMAGE FROM C-CLIP. NEW LIFTER, PUSH ROD AND TUBE INSTALLED. VALVE CLEARANCE CHECKED WITHIN LIMITS, VALVE COVER REINSTALLED WITH NEW GASKET.