Komatsu Galeo PC800-8 User Manual

26 PC800, 850-8
SEN00795-02 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)
• Drop in heat dissipation efficiency
• Problem in coolant circulation system
• Increase of oil temperature
Causes
External leakage of coolant from EGR cooler Broken cylinder head, head gasket Damaged cylinder liner O-ring, hole caused by pitting Clogged, broken oil cooler Lack of coolant Broken water pump Defective operation of thermostat Clogged, crushed radiator fins Clogged radiator core Defective radiator cap (pressure valve) Slipping fan belt, worn fan pulley Defective coolant temperature gauge Decreased performance of fan pump or fan motor
Questions
Confirm recent repair history
Degree of use of
machine
Operated for long period EEE EE
Condition of
overheating
Sudden overheated QQw Q
Always tends to overheat Qww Q
Coolant temperature
gauge (if installed)
Rises quickly Qw
Does not go down from red range
Radiator coolant level monitor indicates drop of coolant level (if monitor is installed) Qw
Engine oil level has risen, oil is milky wQ
Fan speed is low w
Check items
Milky oil is floating on coolant w
There are excessive air bubbles in radiator, coolant spurts back w
When light bulb is held behind radiator core, no light passes through w
Radiator shroud, inside of underguard are clogged with dirt or mud ww
Coolant is leaking because of cracks in hose or loose clamps w
Coolant flows out from radiator overflow hose w
Troubleshooting
Inspect EGR cooler for coolant leakage q
Carry out troubleshooting in H-mode
When compression pressure is measured, it is found to be low q
Inspect cylinder liner directly q
Inspect oil cooler directly q
Temperature difference between upper and lower tanks of radiator is large q
When operation of thermostat is carried out, it does not open at cracking tempera-
ture
q
Temperature difference between upper and lower tanks of radiator is slight q
Inspect radiator core directly q
When operation of radiator cap is carried out, its cracking pressure is low q
Inspect fan directly q
When coolant temperature is measured, it is fount to be normal q
Remedy
Replace Replace Replace Replace Add Replace Replace Correct Correct Replace Correct Replace
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Komatsu Galeo PC800-8 Specifications

General

Brand	Komatsu
Model	Galeo PC800-8
Category	Excavators
Language	English