Komatsu PC138USLC Operation & Maintenance Manual page 174

OPERATION
Check Oil Level in Hydraulic Tank, Add Oil
The parts and oil are at high temperature immediately after the engine is stopped, and may cause burns. Wait for the
temperature to go down before starting the work.
When removing the oil filler cap, turn it slowly to release the internal pressure, then remove it.
1. If the work equipment is not in the position shown in the
diagram on the right, start the engine, run the engine at low
speed, retract the arm and bucket cylinder rods fully, then
lower the boom, set the bucket teeth in contact with the ground,
and stop the engine.
2. Turn the starting switch to the ON position.
3. Within 15 seconds after stopping the engine, move each
control lever (for work equipment and travel) to the full stroke
in all directions to release the internal pressure.
4. Open the door of the pump room on the right side of the
machine, and check sight gauge (G). The oil level should be
between the H and L lines.
NOTICE
Do not add oil above the H line. This will damage the hydraulic circuit or
cause the oil to spurt out.
If oil has been added above the H level, stop the upper structure so that the
drain plug (P) under the hydraulic tank will be between both tracks, and
stop the engine and wait for the hydraulic oil to cool down, then drain the
excess oil from drain plug (P).
MACHINE OPERATIONS AND CONTROLS
WARNING
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