Komatsu SAA6D114E-3 - Coolant Temperature Becomes too High (Overheating)

40 Troubleshooting SEN00458-01
114E-3 Series
21
S-14 Coolant temperature becomes too high (overheating) 1
General causes why coolant temperature becomes too high
q Lack of cooling air (deformation, damage of fan)
q Drop in heat dissipation efficiency
q Problem in coolant circulation system
q Rise in oil temperature in power train
Carry out troubleshooting on applicable machine
Causes
Broken cylinder head, head gasket Holes 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 Rise in power train oil temperature on applicable machine side
Questions
Confirm recent repair history
Degree of use of machine Operated for long period EE EE
Condition of overheating
Suddenly overheated Qw Q
Always tends to overheat Qww Q
Coolant temperature gauge
(if installed)
Rises quickly Qw
Does not go down from red range w
Radiator coolant level monitor indicates drop of coolant level (if monitor is
installed)
w
Engine oil level has risen, oil is milky wQ
Fan belt tension is low w
Check items
When fan pulley is turned, it has play w
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 on applicable machine side 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
Fan belt whines under sudden acceleration w
Power train oil temperature enters red range faster than engine coolant
temperature (if oil temperature gauge and coolant temperature gauge are
installed)
w
Troubleshooting
When compression pressure is measured, it is found to be low q
Carry out troubleshooting
on applicable machine
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
temperature
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 belt, pulley directly q
When coolant temperature is measured, it is found to be normal q
Remedy
Replace Replace Replace
Add
Replace Replace
Correct Correct
Replace
Correct
Replace
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