Coolant Temperature Becomes Too High (Overheating) - Komatsu Galeo PC800-8 Shop Manual

SEN00795-02
S-14 Coolant temperature becomes too high (overheating)
General causes why coolant temperature becomes too high
• Lack of cooling air (deformation, damage of fan)
• Drop in heat dissipation efficiency
• Problem in coolant circulation system
• Increase of oil temperature
Confirm recent repair history
Degree of use of
Operated for long period
machine
Sudden overheated
Condition of
overheating
Always tends to overheat
Rises quickly
Coolant temperature
gauge (if installed)
Does not go down from red range
Radiator coolant level monitor indicates drop of coolant level (if monitor is installed) Q
Engine oil level has risen, oil is milky
Fan speed is low
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 are clogged with dirt or mud
Coolant is leaking because of cracks in hose or loose clamps
Coolant flows out from radiator overflow hose
Inspect EGR cooler for coolant leakage
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 tempera-
ture
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 directly
When coolant temperature is measured, it is fount to be normal
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Causes
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Remedy
40 Troubleshooting
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PC800, 850-8