Komatsu WA380-6 Operation & Maintenance Manual page 182

OPERATION
To warm up the hydraulic oil in cold areas, do as follows.
2. After carrying out the warming-up operation, check that the
engine rotation is smooth, then set the work equipment lock
lever to the FREE position (F).
3. Operate the bucket control lever to the TILT position (A) and
return it to the HOLD position (B) repeatedly to warm up the
hydraulic oil.
Relieve the circuit at the TILT position (A) for a maximum of 10
sec.
This brings the oil to the relief pressure and makes it quicker
warm up the oil.
4. Slowly operate the steering wheel to the left and the right about 10 times to warm up the hydraulic oil inside the
steering valve.
If the steering wheel is operated and stopped while the oil temperature is
low, there may be a time lag before the machine stops turning.
In this case, use the frame lock bar to ensure safety, and perform the
warm-up operation in a wide place.
Do not relieve the hydraulic oil in the circuit continuously for more than 5
seconds.
NOTICE
Turn the steering wheel a little and stop in that position. Confirm that the machine turns by an angle equivalent to the amount that
the steering wheel is turned.
5. After carrying out the warming-up operation, check that the
gauges and caution lamps are normal.
If there is any abnormality, carry out maintenance or repair.
Run the engine under a light load until engine water
temperature gauge (2) and torque converter oil temperature
gauge (3) are in the green range.
6. Check for abnormal exhaust gas color, noise, or vibration. If
any problem is found, contact your Komatsu distributor.
REMARK
The rotating speed of the cooling fan differs according to the following conditions, but this does not indicate any
abnormality.
The cooling fan speed increases when the hydraulic oil temperature, engine coolant temperature, or transmission
oil temperature are high.
However, when the cooling fan is rotating in reverse, it rotates at a fixed speed proportional to the engine speed,
regardless of any oil or coolant temperature.
WARNING
OPERATION
3 - 125