GEAR SET 0006919 - Caterpillar

Probable Causes
Accessory equipment
Valve train components
Pistons
Connecting rod and main bearingsRecommended Actions
Accessory Equipment
Isolate the source of the noise. Remove the suspect engine accessory. Inspect the suspect engine accessory. Repair the engine accessory and/or replace the engine accessory if any defects are found.
If the mechanical noise is still apparent, refer to "Valve Train Components". Valve Train Components
Remove the valve mechanism cover. Check the following items for damage: camshaft, valve springs, lifters, pushrods and bridges. Thoroughly clean the valve train components. If the camshaft is being replaced, also replace the valve lifters. Ensure that all of the valves move freely. Replace any damaged parts.
If the mechanical noise is still apparent, refer to "Pistons". Pistons
Inspect the pistons for damage and wear. Replace any damaged parts.
If the mechanical noise is still apparent, refer to "Connecting Rod and Main Bearings". Connecting Rod and Main Bearings
Inspect the connecting rod and main bearings. Also, inspect the bearing surfaces (journals) on the crankshaft. Replace any damaged parts.If the fault is still apparent, refer to Troubleshooting, "Noise Coming from Cylinder".