GUARD AS-FAN 2563616 - Caterpillar

Rubber Crankshaft Dampers
It is recommended that a rubber crankshaft damper be replaced for any of the following reasons:
* The engine has a broken crankshaft and/or the engine has had a gear train failure.* The crankshaft front bearing is badly worn.* The gear train has a large amount of wear that is not caused by a lack of oil.* Inspection shows slippage (movement), either radially or axially, between the inner and outer members of the damper. [The damper can have visual wobble (movement to the front and rear when in rotation) on the outer ring. This does not mean a replacement is necessary. Some movement of the outer ring is normal.]* Inspection shows rubber deterioration (cracking, spalling, splitting, etc.).The rubber crankshaft damper should also be replaced at overhaul or the following intervals, whichever occurs first:
* 3406 Engines - At 380 000 L (100,000 U.S. Gallons) of fuel used, or 960 000 km (600,000 miles), or 12,000 hours.* 3408 Engines - At 513 000 L (135,000 U.S. Gallons) of fuel used, or 12,000 hours.* 3412 Engines - At 760 000 L (200,000 U.S. Gallons) of fuel used, or 12,000 hours. The 4P-4297 Damper Assembly should be replaced after 250 000 L (67,000 U.S. Gallons) of fuel used, or 640 000 km (400,000 miles), or 8000 hours.Viscous Crankshaft Dampers
The viscous crankshaft damper should be replaced for any of the following reasons:
* The engine has a broken crankshaft and/or the engine has had a gear train failure.* The crankshaft front bearing is badly worn.* The gear train has a large amount of wear that is not caused by a lack of oil.* Inspection shows fluid leakage or a dented (damaged) housing. Either condition can cause the internal metal ring to make contact with the housing and result in incorrect damper operation.If none of the above conditions are found, the viscous crankshaft damper can be used again.