Komatsu PC138USLC Operation & Maintenance Manual page 258

OPERATION
Engine
( ): Always contact your Komatsu distributor when dealing with these items.
In cases of problems or causes which are not listed below, contact your Komatsu distributor for repairs.
Problem
Engine oil pressure monitor lights
up
Steam spurts out from top of
radiator (pressure valve)
Engine water temperature gauge
indicator is in red range
Engine dose not start when
starting motor is turned
Exhaust gas is white or blue
Exhaust gas sometimes becomes
black
Combustion noise occasionally
make breathing sound
Main causes
Oil level low in oil pan (sucking
air in)
Clogging oil filter cartridge
Defective tightening of oil pipe,
pipe joint, oil leakage from
damaged point
Defective engine oil pressure
sensor
Defective monitor
Coolant level low, leakage of
water
Loose fan belt
Dirt scale accumulated in cooling
system
Clogging radiator fins or
damages fins
Defective thermostat
Loose radiator filler cap (high
altitude operations)
Defective monitor
Lack of fuel
Air in fuel system
Defective fuel injection pump or
defective nozzle
Starting motor cranks engine
sluggishly
Pre-heating monitor dose not
light up
Defective compression
( Defective valve clearance)
Too mach oil in oil pan
Improper fuel
Clogging air cleaner element
Defective nozzle
Defective compression
Defective turbocharger
Defective nozzle
TROUBLES AND ACTIONS
Remedy
Add oil to specified level, see
CHECK BEFORE STARTING
Replace cartridge, see EVERY
500 HOURS SERVICR
( Check, repair)
( Replace sensor)
( Replace monitor)
Check, add coolant, repair, see
CHECK BEFORE STARTING
Adjust fan belt tension, see
EVERY 500 HOURS SERVICE
Change coolant, flush inside of
cooling system, see WHEN
REQUIRED
Clean or repair, see EVERY
500 HOURS SERVICE
( Replace thermostat)
Tightening cap or replace
packing
( Replace monitor)
Add fuel, see CHECK BEFORE
STARTING
Repair place where air in
sucked in, see EVERY 500
HOURS SERVICE
( Replace pump or nozzle)
See ELECTRICAL SYSTEM
See ELECTRICAL SYSTEM
( Adjust valve clearance)
Add oil to specified level, see
CHECK BEFORE STARTING
Change to specified fuel
Clean or replace, see WHEN
REQUIRED
( Replace nozzle)
( See "Defective compression")
( Clean or replace turbocharger)
( Replace nozzle)
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