3176C, 3406E and 3456 Industrial Engines Troubleshooting – Engine Has Mechanical Noise (Knock)

Probable Causes


  • Accessory equipment 
  • Valve train components 
  • Pistons 
  • Crankshaft 
  • Gear train 

Recommended 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 necessary.

Valve Train Components

Remove the valve mechanism cover. Check the following items for damage: camshaft, valve rotocoil, valve springs, camshaft followers, rocker shaft, bridges and injectors. 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.


Inspect the pistons for damage and wear. Replace any damaged parts.


Inspect the crankshaft and the related components. Inspect the connecting rod bearings and the bearing surfaces on the crankshaft. Make sure that the bearings are in the correct position. Look for worn thrust plates and wear on the crankshaft. Check the counterweight bolts. Replace any damaged parts.

Gear Train

Inspect the condition of the gear train. Replace any damaged parts.

Inspect the flywheel and the flywheel bolts.

Inspect the engine oil filters for nonferrous material. Flaking of nonferrous material could indicate worn gear train bearings.

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