Fault Phenomenon: Komatsu PC300 excavator hydraulic oil appears milky white, system components abnormally worn.

Troubleshooting Process:
– Checked tank cap: poor seal, rainwater ingress.
– Checked cooler: water cooler internal perforation leaking.
– Checked breather: humid air condensation.
– Checked oil sample: excessive water content.

Root Cause: The hydraulic oil water cooler internally perforated, allowing cooling water to enter the hydraulic system, causing oil emulsification.

Required Parts: Replace hydraulic oil, filter, and repair or replace cooler.