GASKET 9Y5111 - Caterpillar

Illustration 1 g01668376
Variable pitch fan system (1) Fan hub (2) Valve (3) Air pump (A) Filtered airThe variable pitch fan periodically changes the pitch of the fan blades in order to clear the cooling system of debris. Air pump (3) draws filtered air from the engine air intake. The air pump compresses the air to 760 kPa (110 psi). Valve (2) allows the compressed air to flow to fan hub (1). The compressed air moves a piston inside the fan hub. The movement of the piston causes the fan blades to swivel by 90 degrees. This movement will reverse the flow of air through the cooling system.In this position, the fan blades will purge the cooling system of debris. The purge lasts for 20 seconds. When the purge ends, the pump and the valve shut off. When the pump shuts off, the pressure in the fan hub will vent through a vent port on the valve. The fan blades will return to the normal position. The fan will continue to operate in normal mode until the next purge. The default setting for the duration between two purges is 20 minutes. The interval and duration of fan pitch variation can be modified in the engine ecm configuration.The purge cycle may be initiated manually in the monitor display, under the ENGINE menu. Select SETTINGS to get to REVERSING FAN PURGE. The minimum time between purge cycles is 3 minutes. If activated within 3 minutes of the previous cycle, the purge cycle will be delayed until the 3 minutes have passed. Automatic operation will resume after the manual purge is complete.