Fault Phenomenon: Kobelco SK200 excavator after one hour of continuous operation, hydraulic oil temperature exceeds 90°C, machine automatically reduces power.

Troubleshooting Process:
– Checked radiator: hydraulic oil cooler exterior clogged with mud.
– Checked fan: fan motor speed low or belt slipping.
– Checked relief valve: main relief valve in relief state for extended period.
– Checked oil: incorrect oil viscosity.

Root Cause: The surface of the hydraulic oil cooler is completely covered with dust and oil sludge, resulting in almost zero cooling efficiency.

Required Parts: Clean radiator with compressed air or steam.