Komatsu D31EX-21, Operation & Maintenance Manual, Page: 180 / 256

TROUBLESHOOTING
OPERATION
3-128
ENGINE 3
q
( ): Always contact your Komatsu distributor when dealing with these items.
q
In cases of abnormalities or causes which are not listed below, contact your Komatsu distributor for repairs.
Problem Main causes Remedy
Engine oil pressure caution lamp
remains alight when engine speed
is raised after completion of warm-
up
•Engine oil pan oil level is low (suck-
ing air)
•Clogging oil filter cartridge
•Defective tightening of oil pipe, pipe
joint, oil leakage from damaged part
•Defective monitor panel
•Add oil to specified level, see
CHECK BEFORE STARTING
•Replace cartridge, see EVERY
500 HOURS SERVICE
(•Check, repair)
(•Repair)
Steam is emitted from top part of
radiator (pressure valve)
•Cooling water level low, water leak-
age
•Loose fan belt
•Dirt or scale accumulated in cooling
system
•Clogged radiator fin or damaged fin
•Defective thermostat
•Loose radiator filler cap (high alti-
tude operation)
•Defective monitor panel
•Add cooling water, repair, see
CHECK BEFORE STARTING
•Adjust fan belt tension, see
EVERY 250 HOURS SERVICE
•Change cooling water, clean
inside of cooling system, see
WHEN REQUIRED
•Clean and repair, see EVERY
500 HOURS SERVICE
(•Replace thermostat)
•Tighten cap or replace
packing
(•Repair)
Engine water temperature caution
lamp flashes
Engine does not start when starting
motor is turned •Lack of fuel
•Air in fuel system
•Defective fuel injection pump or
nozzle
•Starting motor cranks engine slug-
gishly
•Defective compression
•Defective valve clearance
•Add fuel, see CHECK BEFORE
STARTING
•Repair place where air is sucking
(•Replace pump or nozzle)
•See ELECTRICAL SYSTEM
(•Adjust valve clearance)
Exhaust gas is white or blue •Too much oil in oil pan
•Improper fuel
•Add oil to specified level, see
CHECK BEFORE STARTING
•Change to specified fual
Exhaust gas occasionally turns
black •Clogged air cleaner element
•Defective nozzle
•Defective compression
•Clean or replace, see WHEN
REQUIRED
(•Replace nozzle)
(•Adjust valve clearance)
Combustion noise occasionally
makes breathing sound •Defective nozzle
•Lack of fuel (air in fuel) (•Replace nozzle)
•Add fuel (bleed air)
Abnormal noise generated
(combustion or mechanical) •Low grade fuel being used
•Overheating
•Damage inside muffler
•Excessive valve clearance
•Change to specified fuel
•See item “indicator of water
temperature gauge is in red
range on right side of gauge“
(•Replace muffler)
(•Adjust valve clearance)