Komatsu PC138USLC Operation & Maintenance Manual page 175

MACHINE OPERATIONS AND CONTROLS MACHINE OPERATIONS AND CONTROLS
5. If the oil level is below the L line, add oil through oil filler (F) at
the top of the hydraulic tank.
REMARK
The oil level will vary depending upon the oil temperature.
Accordingly, use the following as a guide:
Before starting operation: Between H and L levels
(Oil temperature 10 to 30°C (50 to 86°F))
Normal operation: Around H level
(Oil temperature 50 to 80°C (122 to 176°F))
3 - 120
OPERATION OPERATION