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Home / Wheel Loaders / Komatsu Wheel Loaders / Komatsu WA70-6

Komatsu WA70-6 Troubleshooting

The Komatsu WA70-6 wheel loader is powered by Komatsu 4D95LWE-5 4-cylinder direct injection water-cooled diesel engine with a rated power of 60.3 hp (45 kW) at 2350 rpm. The Komatsu WA70-6 is equipped with a two-speed hydrostatic transmission, power steering system, hydraulic disc brakes, and 12.5x18 standard tires. The hydraulic system has a pump with fluid flow rate of 14 gpm (53 lpm). The hydraulic pressure is 3335 psi (230 bar). The wheel loader has a rated operating capacity of 4620 lbs (2100 kg) and tipping load of 9240 lbs (4200 kg). The max lift height is 124 inches (3150 mm) to hinge pin, and boom breakout force is 8470 lbs (3850 kg).

Engine Troubleshooting

Engine starts hard or won't start
Air trapped in fuel system - Bleed air.
Fuel filter element is dirty - Service the filter.
Faulty or dirty injection nozzles - If necessary, replace with a new nozzle.
Water or dirt in fuel system - Drain, flush, and service the system.
Valve clearance is out of adjustment - Adjust valve clearance.
Fuel injection pump is broken - Replace or repair injection pump.

Engine starts but immediately stalls
Air cleaner is dirty - Clean or replace element.
Fuel filter element clogging - Change filter element.
Problems with fuel injection pump tightness - Inspect fuel injection pump for leaks.
Fuel injectors are dirty or defective - Clean or replace fuel injectors.
Fuel injection pump is faulty - Change pump or rebuild it.

Diesel shuts off while driving
Coolant temperature is low - Warm up the engine.
Dirty fuel filter - Clean or change the filter.
Air trapped in fuel system - Bleed air.
Faulty or dirty injection nozzles - If necessary, replace with a new nozzle.
Timing of fuel injection pump is incorrect - Adjust fuel injection pump as required.

Engine stops at low idle speed
Incorrect low idle speed adjustment - Adjust the low idle speed.
Fuel injection pump is not working correctly - Install a new fuel pump or repair.
Fuel injector fault - Inspect fuel injectors and change as required.
Improper valve clearance - Check and adjust as required.

Engine power is too low
Clogged air cleaner - Service or replace air cleaner.
Clogged or burnt injection nozzle - Inspect nozzles and replace if necessary.
Fuel injection pressure is wrong - Test fuel injection pressure and adjust it correctly.
Incorrect valve clearance - Check and adjust.
Incorrect low idle setting - Correct the settings.
Restricted fuel hoses or lines - Clean fuel lines and hoses.
Worn cylinder head gasket - Replace cylinder head gasket.
Leaking or defective piston rings - Change piston rings.

Engine is overheated
Low engine coolant - Fill the cooling system and check components for leaks or other faults.
Engine oil level low - Checking oil level and add if necessary.
Dirty radiator core or faulty radiator cap - Clean radiator or replace cap.
Fan belt is loose or defective - Change as required.
Diesel engine is overloaded - Load reducing required.

Low oil pressure
Engine oil level low - Add oil to the engine crankcase.
Oil filter is clogged - Replace or clean engine oil filter element.
Improper type of engine oil - Use oil of proper viscosity.
Main bearing oil clearance is excessive - Install new bearings.
Oil pump failure - Remove and inspect oil pump.

Engine knocking or noise
Engine oil level low - Fill up the engine oil.
Engine is not preheated - Normalize the temperature by warming up the engine.
Improper setting of fuel injection pump timing - Adjust fuel injection pump as required.
Incorrectly adjusted low idle speed - Adjust low idle speed.
Fuel injector fault - Inspect fuel injectors and change as required.
Misaligned or defective connecting rod - Align or replace connecting rod.
Pistons are scored or worn - Pistons replacement required.

Hydrostatic Transmission Troubleshooting

Hydrostatic transmission makes noise
Dirty transmission fluid or insufficient fluid level - Pour fresh fluid or add transmission fluid to proper level.
Worn or unadjusted speed control linkage - Adjust or replace linkage.
Defective relief valve - Change the valve.
Transmission is under excessive load - The load should be reduced.
Transmission components are damaged or worn - After disassembly and inspection, replace defective components.

Loss of power
Low oil level - Need to add transmission oil.
Relief valve failure - Replace relief valve.
Worn or out of adjustment speed control linkage - Adjust or change linkage.

Transmission oil overheating
Low fluid level - Need to add transmission fluid.
Dirty transmission oil filter element - Clean or change transmission oil filter.
Cooling components are defective or plugged - Check all cooling components and clean or replace if required.
Transmission overloaded - Reduce transmission load.

Transmission oil leaks
Seals or gaskets are worn - Gaskets or seal replacement required.
High internal transmission housing pressure - Check hydrostatic transmission components for defect or damage and change if necessary.
Clogged oil return pipe - Clean or change return pipe.

Hydraulics Troubleshooting

Hydraulic system is overheated
Hydraulic pressure is not correct - Hydraulic pressure must be set correctly.
Main relief valve malfunction or improper adjustment - Adjust or replace the relief valve.
Contaminated hydraulic oil - Change hydraulic oil.
Not enough hydraulic oil in the system - Fill the hydraulic system with oil.
Faulty hydraulic oil pump - Change or repair hydraulic pump if required.

Lift arm cannot be raised or lowered
Damaged lift controls - Replace or repair.
Defective hydraulic pump - Install new pump or repair it.
Faulty hydraulic control valve - Repair or change hydraulic valve.
Broken hydraulic cylinder - Repair or replace hydraulic cylinder.
Low hydraulic oil level - Need to add oil.

Bucket can't tilt
Bucket tilt controls are defective - Check and repair as required.
Damaged hydraulic oil pump - Install new pump or repair it.
Defective hydraulic control valve - Change or repair hydraulic valve.
Bucket cylinder malfunction - Replace or repair cylinder.
Insufficient hydraulic oil - Checking hydraulic oil level and add if necessary.

Bucket or lift arm functions slowly
Hydraulic pump is faulty - Check pump capacity and change if necessary.
Leaking hydraulic cylinder - Correct leakage by changing the seals.
Hydraulic oil level low - Checking hydraulic oil level and add if necessary.
Hydraulic control valve is unadjusted or worn - Repair or set correctly.
Low hydraulic pressure - Adjust pressure as required.

Lift arm or bucket jerks when working
Air trapped in hydraulic system - Need to bleed air.
Plugged hydraulic oil filter - Clean or install new filter.
Hydraulic oil is contaminated - Fill up with fresh hydraulic oil.
Cylinder tube or rod is scored - Change damaged component.

Hydraulic pump makes excessive noise
Not enough oil or hydraulic system leaking - Repair hydraulic leaks or add oil as required.
Plugged hydraulic filter - Service or replace hydraulic filter.
Plugged suction line - Need to clean the suction line.
Air enters the pump - Remove air from hydraulics.
Faulty pump components - Install new hydraulic pump or rebuild it.

Electrical Troubleshooting

Battery will not charge
Loose or corroded electrical wiring connections - Clean or tighten wiring connections.
Battery terminal clamps are faulty - Terminal clamps need to be replaced.
Battery is defective - Use a new battery.
Defective or loose belt - Change belt or adjust belt tension.

Starter motor turns slow
Low battery voltage - Recharge the battery.
Battery drains quickly - Service or change the battery.
Disconnected wires or corroded battery terminals - Check wiring connections and replace or clean terminals.

Starter motor is not working
Battery is drained or worn - Need to charge or replace the battery.
Wiring is incorrectly connected or disconnected - Inspect wiring and connect correctly.
Low battery power - Charge the battery.
Faulty starter motor - Replace or repair starter.

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WHEEL LOADERS SPECIFICATIONS

Wheel Loaders, Skid Steers, and Compact Track Loaders