Fault Phenomenon: John Deere 772G grader high water temperature, but the fan speed remains very low, not changing with temperature.

Troubleshooting Process:
– Checked silicone clutch: silicone leaked, unable to engage.
– Checked temperature-sensing spring: bimetallic spring failed.
– Checked fan blades: blades deformed.
– Checked belt: belt normal.

Root Cause: Silicone oil leaked from the fan silicone clutch, preventing engagement; the fan remained disengaged, resulting in insufficient airflow.

Required Parts: Fan silicone clutch assembly.