Water Temperature Becomes Too High (Overheating) - Komatsu PC130-7 Shop Manual

TROUBLESHOOTING
S-14 Water temperature becomes too high
(Overheating)
General causes why water temperature becomes too
high
• Lack of cooling air (deformation, damage of fan)
• Drop in heat dissipation efficiency
• Defective cooling circulation system
• Rise in oil temperature in power train
a Carry out troubleshooting for chassis.
Confirm recent repair history
Degree of use of machine
Condition of overheating
Water temperature
gauge
Radiator water level sensor lights up
Fan belt whines under sudden load
Cloudy white oil is floating on cooling water
Cooling water flows out from overflow hose
Excessive air bubbles inside radiator, water spurts back
Engine oil level has risen, oil is cloudy white
There is play when fan pulley is rotated
Radiator shroud, inside of underguard are clogged with dirt or mud
When light bulb is held behind radiator, no light passes through
Water is leaking because of cracks in hose or loose clamps
When belt tension is inspected, it is found to be loose
Power train oil temperature enters red range faster than
engine water temperature
Temperature difference between top and bottom radiator tanks
is excessive
Temperature difference between top and bottom radiator tanks
is slight
When water filler port is inspected, core is found to be clogged
When function test is carried out on thermostat, it does not
open even at cracking temperature
When water temperature is measured, it is found to be normal
When oil cooler is inspected directly, it is found to be clogged
When measurement is made with radiator cap tester, set
pressure is found to be low
When compression pressure is measured, it is found to be low
Remove oil pan and inspect directly
20-622
(1)
Operated for long period
Suddenly overheated
Always tends to overheat
Rises quickly
Does not go down from red range
Remedy
Causes
—
PC130-7
S-14