3.7 Troubleshooting Operation Engine z ( ): Always contact your KOMATSU distributor when deal- ing with these items. z In cases of abnormalities or causes which are not listed below, please contact your KOMATSU distributor for repairs. 3-120 WA150-5H – VEAM934100 Problem Main causes Remedy Engine oil pressure caution pilot lamp lights up z Low engine oil pan oil level (sucking in air) z Clogged oil filter cartridge z Defective tightening of oil pipe joint, oil leakage from damaged part z Defective monitor z Add oil to specified level. See CHECK BEFORE START- ING z Replace cartridge.
See EVERY 500 HOURS SER- VICE z (Check, repair) z (Replace) Steam is emitted from top part of radiator (pressure valve) Engine coolant temperature gauge is in red range Engine coolant temperature moni- tor lights up z Low coolant level, leakage of water z Defective fan pump motor z Dirt or scale accumulated in cooling system z Clogged radiator fin or damaged fin z Defective thermostat z Loose radiator filler cap (high altitude operation) z Defective monitor z Check, add coolant, repair. See WHEN REQUIRED z (Check, repair) z Change coolant, clean inside of cooling system. See WHEN REQUIRED z Clean or repair.
See WHEN REQUIRED z (Replace thermostat) z Tighten cap or replace packing z (Replace) Engine coolant temperature gauge is in white range on left z Defective thermostat z Defective monitor z (Replace thermostat) z (Replace) Engine does not start when starting motor is turned z Lack of fuel z Air in fuel system z No fuel in fuel filter z Defective injection pump or noz- zle z Starting motor cranks engine too slowly z Starting motor does not turn z Preheating pilot lamp does not light up z Defective valve clearance (Defective compression) z Add fuel. See CHECK BEFORE START- ING z Repair place where air is sucked in z Fuel filter with fuel.
See EVERY 500 HOURS SER- VICE z (Replace pump or nozzle) See ELECTRICAL SYSTEM z (Adjust valve clearance) Exhaust gas is white or blue z Too much oil in oil pan z Improper fuel z Add oil to specified level. See CHECK BEFORE START- ING z Change to specified fuel Exhaust gas occasionally turns black z Clogged air cleaner element z Defective nozzle z Defective compression z Defective turbocharger z Clean or replace.
See WHEN REQUIRED z (Replace nozzle) z (See defective compression above) z Clean or replace turbocharger Combustion noise occasionally makes breathing sound z Defective nozzle z (Replace nozzle) Abnormal noise generated (com- bustion or mechanical) z Low grade fuel being used z Overheating z Damage inside muffler z Excessive valve clearance z Change to specified fuel z Refer to “Engine coolant temper- ature gauge is in red range“ as above z (Replace muffler) (Adjust valve clearance)