Komatsu D155A-6 Operation & Maintenance Manual page 236

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
After warming up, engine speed
rises but engine oil pressure
caution lamp flashes
Steam spurts out from top of
radiator (pressure valve)
Red range at top of engine coolant
temperature gauge flashes
White range at bottom of engine
coolant temperature gauge flashes
Starting motor turns but engine
does not start
Exhaust gas is white or bluish
Exhaust gas sometimes becomes
black
Combustion sometimes makes
breathing noise
Abnormal sound is generated
(combustion or mechanical)
Main causes
Lack of oil in oil pan (air being
sucked in)
Clogged oil filter cartridge
Defective tightening of oil pipe,
pipe joint, oil leakage from
damage
Defective caution lamp
Lack of cooling water, water
leakage
Dirt or scale accumulated in
cooling system
Clogged or damaged radiator
fins
Defective thermostat
Loose radiator filler cap (when
operating at high altitudes)
Defective monitor panel
Defective thermostat
Defective monitor panel
Lack of fuel
Air entering fuel line
No fuel inside fuel filter
Cranking of engine by starting
motor is slow
Glow signal does not become red
Defective compression
Defective valve clearance
Too much oil in oil pan
Improper fuel
Clogged air cleaner element
Defective nozzle
Defective compression
Defective nozzle
Low-grade fuel being used
Overheating
Breakage inside muffler
Excessive valve clearance
TROUBLESHOOTING
Remedy
Add oil to specified level. See
Check before Starting
Replace. See EVERY 500
HOURS SERVICE
( Check, repair)
( Replace)
Check, add cooling water, repair.
See Check before Starting
Change coolant, flush inside of
cooling system. See WHEN
REQUIRED
Clean or repair. See WHEN
REQUIRED
( Replace thermostat)
Tighten cap or replace packing
( Replace monitor panel)
( Replace thermostat)
( Replace monitor panel)
Add fuel. See Check before
Starting
Repair places where air enters
fuel line
( Fill fuel filter with fuel. See
EVERY 500 HOURS SERVICE.)
See ELECTRICAL SYSTEM
See ELECTRICAL SYSTEM
( Adjust clearance)
Drain excess oil. See Check
before Starting
Replace with specified fuel
Clean or replace. See WHEN
REQUIRED
( Replace nozzle)
( See "Defective compression"
above)
( Replace nozzle)
Replace with specified fuel
See "Red range at top of engine
coolant temperature gauge
flashes" above
( Replace muffler)
( Adjust clearance)
3 - 185