JET AS-PISTON COOLING 9Y4121 - Caterpillar

The crankshaft vibration damper limits the torsional vibration of the crankshaft. The visconic damper has a weight that is located inside a fluid filled case. Damage to the crankshaft vibration damper or failure of the damper can increase torsional vibrations. This can result in damage to the crankshaft and to other engine components. A deteriorating damper can cause excessive gear train noise at variable points in the speed range.A damper that is hot is due to excessive torsional vibration. Monitor the temperature of the damper during operation.The 8T-2821 Temperature Indicator or the 8T-2822 Temperature Indicator are recommended for monitoring the temperature of the damper. Evenly space four of the adhesive indicators around the outer diameter of the damper.Note: If you use an infrared thermometer to monitor the temperature of the damper, use the thermometer during operation with similar loads and speeds. Keep a record of the data. If the temperature begins to rise, reduce the interval for inspecting the damper.If the temperature of the damper reaches 110 °C (230 °F), consult your Caterpillar dealer.Inspect the damper for evidence of dents, cracks, and leaks of the fluid.If a fluid leak is found, repair the damper or replace the damper. The fluid in the damper is silicone. Silicone has the following characteristics: transparent, viscous, smooth and sticky.Inspect the damper and repair or replace the damper for any of the following reasons.
The damper is dented, cracked, or leaking.
The paint on the damper is discolored from heat.
The engine has had a failure because of a broken crankshaft.
An analysis of the oil has revealed that the front bearing of the crankshaft is badly worn.
There is a large amount of gear train wear that is not caused by a lack of oil.Removal and Installation
Refer to the Service Manual, "Disassembly and Assembly" or consult your Caterpillar dealer for information about damper replacement.