ROD AS 3763921 - Caterpillar

Probable Causes
Lubrication
Valve train componentsRecommended Actions
Lubrication
Ensure that the engine oil pressure is satisfactory. Low engine oil pressure can cause excessive component wear.
Remove the valve mechanism cover. Refer to Disassembly and Assembly, "Valve Mechanism Cover - Remove and Install" for the correct procedure.
Crank the engine and check the lubrication in the valve compartment. Ensure that there is adequate engine oil flow in the valve compartment. The passages for the engine oil must be clean. Note: Do not run the engine without the valve mechanism cover.Valve Train Components
Check the hydraulic lifters for correct operation. Refer to Systems Operation, Testing, and Adjusting, "Engine Valve Lash - Inspect".
Inspect the following components of the valve train. Refer to Disassembly and Assembly for any components that must be removed for inspection.
Rocker arms
Valve bridges
Pushrods
Hydraulic lifters
Camshaft
Valve stems
Rocker shaft
Check the components for the following conditions: abnormal wear, excessive wear, straightness and cleanliness. If necessary, use new parts for replacement. Note: If the camshaft is replaced, new valve lifters must also be used.