Komatsu PC138US-11 Operation & Maintenance Manual page 109

OPERATION
Red range (A) position: Engine coolant temperature caution lamp (E) shows abnormality display.
Red range (B) position: Engine speed changes to low idle, engine coolant temperature caution lamp (E) shows
abnormality display and alarm buzzer sounds at the same time
The overheat prevention system continues to operate until the pointer enters the green range.
When the engine is started, if the indicator is at position (D), engine coolant temperature caution lamp (E) shows
the low-temperature display.
In this case, perform warm-up operation. For details, see "METHOD FOR ENGINE WARM-UP OPERATION
(3-159)".
Display (G) when temperature is low: Caution lamp background
(K) is white.
Display (H) when temperature is correct: Caution lamp back-
ground (K) is blue.
Display (J) when condition is abnormal: Caution lamp back-
ground (K) is red.
HYDRAULIC OIL TEMPERATURE GAUGE
Hydraulic oil temperature gauge shows the hydraulic oil tem-
perature.
If the indicator is in green range during operations, it is normal.
When the indicator nears the red range (A) during operation,
the hydraulic oil temperature has exceeded 102 °C. Then run
the engine at low idle or stop it and wait for the hydraulic oil
temperature to drop.
(A) to (B): Red range
(A) to (C): Green range
(C) to (D): White range
REMARK
When the indicator reaches red range (A), the hydraulic oil temperature is as follows.
Red range (A) position: 102 °C or more
Red range (B) position: 105 °C or more
When the indicator is in red range (A) to (B), hydraulic oil temperature caution lamp (E) indicates abnormality.
When the engine is started, if the indicator is at position (C), the hydraulic oil temperature is below 20 °C and
hydraulic oil temperature caution lamp (E) indicates low temperature. In this case, perform warm-up operation.
For details, see "METHOD FOR HYDRAULIC SYSTEM WARM-UP OPERATION (3-161)".
Display (G) when temperature is low: Caution lamp background
(K) is white.
Display (H) when temperature is correct: Caution lamp back-
ground (K) is blue.
Display (J) when condition is abnormal: Caution lamp back-
ground (K) is red.
WENAM00111
EXPLANATION OF COMPONENTS
3-39