Coolant Temperature Becomes Too High (Overheating) - Komatsu PC130-8 Shop Manual

40 Troubleshooting
S-14 Coolant temperature becomes too high (overheating)
General causes why coolant temperature becomes too high
Lack of cooling air (deformation, damage of fan)
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q Drop in heat dissipation efficiency
q Problem in coolant circulation system
Confirm recent repair history
Degree of use of machine
Condition overheating
Coolant temperature gauge
Radiator coolant level monitor indicates drop of coolant level
Engine oil level has risen, oil is milky
Fan belt tension is low
When fan pulley is turned, it has play
Milky oil is floating on coolant
There are excessive air bubbles in radiator, coolant spurts back
When light bulb is held behind radiator core, no light passes through
Radiator shroud, inside of underguard side are clogged with dirt or mud
Coolant is leaking because of cracks in hose or loose clamps
Coolant flows out from radiator overflow hose
Fan belt whines under sudden acceleration
Hydraulic oil temperature enters red range faster than engine coolant
temperature
When compression pressure is measured, it is found to be low
Inspect cylinder liner directly
Inspect oil cooler directly
Temperature difference between upper and lower tanks of radiator is large
When operation of thermostat is carried out, it does not open at cracking
temperature
Temperature difference between upper and lower tanks of radiator is slight
Inspect radiator core directly
When operation of radiator cap is carried out, its cracking pressure is low
Inspect fan belt, pulley directly
When coolant temperature is measured, it is found to be normal
PC130-8
Operated for long period
Sudden overheated
Always tends to overheat
Rises quickly
Does not go down from red range
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Remedy
SEN04125-02
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Causes
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