Komatsuengine(no series)

Komatsu 3D72-2G(S/N 02519-UP)

Maintenance schedule, common problems & OEM parts breakdown

The Komatsu 3D72-2G (S/N 02519-UP) is a diesel engine powering the PC07-2 mini excavator, a compact crawler class machine designed for utility and light construction work. Production years for this specific serial range are not documented in the available sources. The 3D72-2G belongs to the 3D72 series, which also includes variants like the 3D72-2F and 3D72-2GA. The PC07-2 is part of Komatsu's mini excavator lineage, succeeding earlier PC05 models and preceding later PC07 iterations. Configurations offered for the PC07-2 include standard and wide track shoe options, with operating weights varying by configuration.

Across the 3D72 series generations, Komatsu refined emissions compliance and fuel injection precision, with the 2G variant representing a specific production update within the PC07-2 line. The 3D72-2G remains relevant in the used and parts market because the PC07-2 is a high-volume entry-level excavator with widespread global deployment. Its simple mechanical architecture and commonality with other 3D72-series engines (like the 3D72-2B and 3D72-2H) ensure a robust aftermarket support network for overhaul kits, gaskets, and undercarriage components. The machine's compact size and durability make it a staple in rental fleets and municipal contracts, driving consistent demand for serviceable units and replacement parts.

Below: full specifications, fluids & capacities, the factory service schedule, common service parts, verified fault codes, what owners discuss, attachment guidance, the complete assembly directory, and a serial-number reference. Complete parts lists with full OEM part numbers, exploded diagrams, quantities, and fitment data are available free in Heavy Parts AI.

Komatsu 3D72-2G(S/N 02519-UP) specifications

Engine

Model3D72-2G
Series72 Series
Cylinders3
DisplacementNot documented for this exact serial range — verify with your dealer
Gross/Net PowerNot documented for this exact serial range — verify with your dealer
Emissions TierNot documented for this exact serial range — verify with your dealer

Weights

Operating WeightNot documented for this exact serial range — verify with your dealer
Shipping WeightNot documented for this exact serial range — verify with your dealer
Ground PressureNot documented for this exact serial range — verify with your dealer

Dimensions

Transport LengthNot documented for this exact serial range — verify with your dealer
Transport WidthNot documented for this exact serial range — verify with your dealer
Transport HeightNot documented for this exact serial range — verify with your dealer
Track GaugeNot documented for this exact serial range — verify with your dealer
Ground ClearanceNot documented for this exact serial range — verify with your dealer

Performance

Travel SpeedNot documented for this exact serial range — verify with your dealer
GradeabilityNot documented for this exact serial range — verify with your dealer

Service capacities (summary)

Fuel TankNot documented for this exact serial range — verify with your dealer
Hydraulic SystemNot documented for this exact serial range — verify with your dealer
Engine OilNot documented for this exact serial range — verify with your dealer
Cooling SystemNot documented for this exact serial range — verify with your dealer

Values vary by configuration, region, and serial range — confirm against your machine before planning transport or lifts.

Komatsu 3D72-2G(S/N 02519-UP) maintenance schedule

Service intervalTasks
Every 10 h
  • Check engine oil level and condition.
  • Check hydraulic fluid level via sight glass.
  • Check coolant level and ensure cap is secure.
  • Drain water from fuel separator.
  • Check air filter restriction indicator.
  • Inspect hydraulic hoses for cracks or leaks.
Every 250 h
  • Change engine oil and filter.
  • Grease all points (boom, stick, bucket, swing bearing).
  • Check fuel and hydraulic systems.
  • Inspect undercarriage rollers, sprockets, and idlers.
  • Inspect belts, hoses, and clamps.
  • Check final drive oil level.
Every 500 h
  • Replace fuel filter.
  • Replace hydraulic return filter.
  • Perform KOWA oil sample analysis.
  • Test coolant SCA concentration.
  • Load test battery and alternator.
  • Measure undercarriage wear.
Every 1,000 h
  • Replace hydraulic oil.
  • Change final drive oil (both sides).
  • Clean or replace air filter outer element.
  • Inspect turbocharger.
  • Check swing machinery and travel system.
  • Inspect exhaust system and electrical wiring.
Every 2,000 h
  • Flush and replace coolant.
  • Replace hydraulic hoses.
  • Inspect final drives comprehensively.
  • Inspect pump system thoroughly.
  • Perform comprehensive structural inspection.
  • Replace worn belts and clamps.
Every 4,000 h
  • Inspect swing circle carefully.
  • Inspect undercarriage components.
  • Replace key worn parts to maintain performance.
  • Check transmission/torque converter oil.
  • Inspect differential oil.
  • Verify brake system function.

Servicing the 3D72-2G(S/N 02519-UP) beyond the schedule

Predictive Maintenance & Fluid Analysis

Utilize Komatsu Oil Wear Analysis (KOWA) at every 500-hour interval to monitor engine oil wear metals (iron, copper, lead, aluminum) and contaminants (silicon for dirt, sodium for coolant). Check coolant pH, SCA concentration, and glycol content to prevent corrosion in the 3D72-2G cooling system. Monitor hydraulic fluid particle count (ISO cleanliness) and viscosity to protect the main pump and control valves. Track DEF levels for Tier 4 compliance. Early detection of coolant intrusion or fuel dilution in the 3D72-2G engine oil prevents catastrophic bearing failure.

Corrective & Common Repairs

Address frequent 3D72-2G issues by inspecting the fuel injection pump and piping for leaks, especially around the fuel nozzle and spill pipe. Replace the fuel filter and drain the water separator regularly to prevent injector clogging. Check the glow plug timer and safety relay for starting failures in cold weather. Inspect the alternator and starting motor mounts for vibration damage. Tighten the cylinder head bolts to spec if compression loss occurs. Replace worn hydraulic hoses at the 2,000-hour mark to prevent high-pressure leaks near the engine compartment.

Overhaul & Rebuild Points

The 3D72-2G engine overhaul typically begins around 10,000-15,000 hours, depending on duty cycle. Key rebuild components include cylinder liners, pistons, piston rings, and rod bushings. Replace main and rod bearings, thrust washers, and valve guides. Inspect the crankshaft for wear and the cylinder block for cracks. Use a complete overhaul gasket kit including the head gasket. For the PC07-2 undercarriage, replace track chains, sprockets, and idlers when wear limits are reached to maintain traction and reduce powertrain strain on the 3D72-2G engine.

Seasonal & Environment Servicing

In cold climates, ensure the 3D72-2G engine uses the correct viscosity diesel engine oil (e.g., SAE 5W-30 or 10W-30) and verify glow plug operation. Drain water from the fuel separator daily to prevent freezing. In dusty environments, clean the air cleaner outer element frequently and replace it when the restriction indicator triggers. Inspect the radiator and oil cooler fins for debris buildup to prevent overheating. In humid conditions, check for coolant contamination and monitor hydraulic oil for water ingress. Adjust track tension for muddy or rocky terrain to reduce undercarriage wear.

3D72-2G(S/N 02519-UP) common service parts

Part numberPart
YM119640-55600Fuel Filter Ass'YCheck fitment →
YM102103-55520O-Ring,(For Fuel Filter)Check fitment →
YM124550-55700Element,Fuel FilterCheck fitment →
(YM171051-92760)Wrench,Fuel Filter? Water SeparatorCheck fitment →
YM121420-01760O-Ring,Oil FilterCheck fitment →

Always confirm against your machine's serial number — cross-check any part in Heavy Parts AI before ordering.

3D72-2G(S/N 02519-UP) fault codes & troubleshooting

CodeMeaningLikely causeWhat to do
CA115Engine crankshaft speed sensor failureBroken sensor, wiring issue, or connector corrosionReplace the speed sensor and verify voltage at the pin connector
CA111Internal engine controller faultECM hardware failureReplace or reprogram the ECM
CA441Battery voltage too lowWeak battery or charging system issueReplace the alternator or battery; check the voltage regulator
CA442Battery voltage too highFaulty voltage regulator or alternatorReplace the alternator or battery; check the voltage regulator
CA122Intake air pressure high voltageSensor malfunction or actual overpressureVerify the intake pressure sensor and wiring
CA123Intake air pressure low voltageSensor short or airflow restrictionCheck for a sensor short or an airflow restriction
CA451Common rail pressure sensor feedback value too highMalfunction in the rail sensor or actual overpressure conditionDiagnose the fuel rail pressure sensor or pump lines
CA452Common rail pressure sensor feedback value too lowSensor failure or low fuel pressureDiagnose the fuel rail pressure sensor or pump lines
AA10NXAir cleaner cloggingDirty or blocked air filter elementReplace the air filter
AB00KECharge voltage too lowAlternator failure or loose beltReplace the alternator or tighten the belt

Codes and remedies are general guidance for this model family — always confirm with diagnostic tooling and your dealer before major repairs.

3D72-2G(S/N 02519-UP) attachments & work tools

Excavator Attachments

The Komatsu 3D72-2G engine powers the PC07-2 mini excavator, which utilizes standard hydraulic quick couplers for bucket and tool interchange. Typical bucket widths for this class range from 300 mm to 600 mm, with capacities varying by configuration/series based on material density and application.

Hydraulic System Configuration

The engine drives a main hydraulic pump assembly requiring specific flow rates for attachment operation. Hydraulic oil specifications include Komatsu HO or equivalent ISO VG46 hydraulic fluid to maintain pump integrity and attachment responsiveness.

Engine Mounting and Guarding

The 3D72-2G is mounted within the PC07-2 chassis using specific engine mounting brackets and vibration dampers. Factory configurations include the engine stop motor, governor control, and fuel filter assemblies located for service access, with guarding options for the cooling system and exhaust manifold.

All 3D72-2G(S/N 02519-UP) assemblies by section

Every catalogued assembly group for the Komatsu 3D72-2G(S/N 02519-UP). Open an assembly to preview the parts inside — full OEM part numbers are available in Heavy Parts AI.

Cooling System
Komatsu : 3d72-2g(S/N 02519-Up) : Cooling System : Water Pump And Cooling Fan
YM***20O-Ring1
YM***02Bolt Plated2
YM***40Packing1
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Cylinder Block
Komatsu : 3d72-2g(S/N 02519-Up) : Cylinder Block : Camshaft And Tappet
YM***00Gear,Camshaft1
YM***00Rod,Push6
YM***50Retainer, Bearing1
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Komatsu : 3d72-2g(S/N 02519-Up) : Cylinder Block : Crankshaft
YM***80Bolt1
YM***41Washer1
YM***20Wrench1
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Komatsu : 3d72-2g(S/N 02519-Up) : Cylinder Block : Cylinder Block
YM***20Plug,Drain(Without Oil Cooler Type)1
YM***00Main Metal Ass'Y (Std)4
YM***00Plug1
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Komatsu : 3d72-2g(S/N 02519-Up) : Cylinder Block : Flywheel And Flywheel Housing(#03753-)
YM***20Bolt Plated3
YM***90Flywheel Ass'Y1
YM***20Parallel Pin2
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Komatsu : 3d72-2g(S/N 02519-Up) : Cylinder Block : Gear Case And Front Cover(#03753-)
YM***22Retainer, Idle Gear1
YM***51Cap, Lub. Oil Supply1
YM***92Case,Gear1
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Komatsu : 3d72-2g(S/N 02519-Up) : Cylinder Block : Oil Pan
YM***52Bolt Plated20
YM***40O-Ring,Drain Plug1
YM***12Liquid Gasket1
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Komatsu : 3d72-2g(S/N 02519-Up) : Cylinder Block : Piston And Connecting Rod
YM***10Crank Pin Metal A.,0.25mm (Us)1
YM***00Piston Ring Ass'Y1
YM***00Connecting Rod, Assembly3
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Cylinder Head
Komatsu : 3d72-2g(S/N 02519-Up) : Cylinder Head : Air Cleaner
YM***10Cap1
YM***11Air Cleaner Ass'Y1
YM***00Valve1
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Komatsu : 3d72-2g(S/N 02519-Up) : Cylinder Head : Air Intake Manifold And Glow Plug
YM***20Wire,Glow Plug1
YM***62Bolt Plated2
YM***01Manifold,Air Intake1
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Komatsu : 3d72-2g(S/N 02519-Up) : Cylinder Head : Cylinder Head
YM***80Retainer, Spring6
YM***00Bolt,Head14
YM***10Insert3
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Komatsu : 3d72-2g(S/N 02519-Up) : Cylinder Head : Cylinder Head Cover
YM***00Pipe,Breather1
YM***51Cap, Lub. Oil Supply1
YM***30Gasket1
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Komatsu : 3d72-2g(S/N 02519-Up) : Cylinder Head : Exhaust Manifold And Muffler(#03753-)
YM***50Pipe1
YM***62Bolt2
YM***50Stay1
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Komatsu : 3d72-2g(S/N 02519-Up) : Cylinder Head : Rocker Arm
YM***30Screw,Adjusting2
YM***62Screw1
YM***02Nut2
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Electrical System
Komatsu : 3d72-2g(S/N 02519-Up) : Electrical System : Alternator
YM***01Alternator A. (20a)1
YM***00Stator Ass'Y1
YM***10Bearing,Ball1
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Komatsu : 3d72-2g(S/N 02519-Up) : Electrical System : Alternator And Mounting
YM***02Screw1
YM***62Bolt,(For Shipping)1
YM***52Screw1
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Komatsu : 3d72-2g(S/N 02519-Up) : Electrical System : Safety Relay Glow Plug Timer(#03753-)
(Y***0)Feed Pump Ass'Y,Fuel1
(Y***1)Relay,Safety (Not Shown)2
(Y***1)Indicator, Charging1
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Komatsu : 3d72-2g(S/N 02519-Up) : Electrical System : Starting Motor
YM***01Washer,Spring1
YM***20Cover1
YM***51Nut1
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Komatsu : 3d72-2g(S/N 02519-Up) : Electrical System : Starting Motor And Mounting
YM***52Bolt Plated2
(Y***1)Starting Motor Ass'Y,(See Fig.A6210-B0a1)1
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Fuel System
Komatsu : 3d72-2g(S/N 02519-Up) : Fuel System : Engine Stop Motor(#03753-)
YM***80Ring,Snap1
YM***00Pin,Cotter1
YM***20Spring1
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Komatsu : 3d72-2g(S/N 02519-Up) : Fuel System : Fuel Filter(#03753-)
YM***00O-Ring (Kit)1
YM***20Spring1
YM***41Handle, Cock1
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Komatsu : 3d72-2g(S/N 02519-Up) : Fuel System : Fuel Injection Pump
YM***00Valve W/Seat, Deliv3
YM***00Washer,Spring2
YM***00Washer2
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Komatsu : 3d72-2g(S/N 02519-Up) : Fuel System : Fuel Injection Pump And Piping(#03753-)
YM***20Retainer, Pipe1
YM***21Pipe,Injection? No.21
YM***50Shim Ass'Y1
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Komatsu : 3d72-2g(S/N 02519-Up) : Fuel System : Fuel Nozzle And Spill Pipe
YM***40Spacer, Valve Stop1
YM***00Sleeve1
YM***80Nut1
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Komatsu : 3d72-2g(S/N 02519-Up) : Fuel System : Governor Control(#03753-)
YM***50Nut,Lock1
YM***00Pin, Cotter1
YM***00Retainer, Shaft1
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Komatsu : 3d72-2g(S/N 02519-Up) : Fuel System : Water Separator(#03753-)
YM***00Gasket2
YM***00O-Ring (Kit)1
YM***50Plug,Air2
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Lubricating Oil System
Komatsu : 3d72-2g(S/N 02519-Up) : Lubricating Oil System : Lubricating Oil Filter
YM***50Nut1
YM***02Bolt Plated3
YM***50Cartridge1
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Komatsu : 3d72-2g(S/N 02519-Up) : Lubricating Oil System : Lubricating Oil Pump
YM***50Oil Pressure Transmitter1
YM***91Pipe,Oil Inlet1
YM***20O-Ring,Cylinder Head Cover Bolt1
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Tool And Kit
Komatsu : 3d72-2g(S/N 02519-Up) : Tool And Kit : Gasket Kit
YM***40O-Ring,Drain Plug1
YM***40Gasket,Head (Kit)1
YM***10Gasket,Exhaust Manifold (Kit)1
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Komatsu : 3d72-2g(S/N 02519-Up) : Tool And Kit : Tool
(Y***0)Wrench,Oil Filter1
(Y***0)Tool Ass'Y1
(Y***0)Driver,Screw1
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3D72-2G(S/N 02519-UP) serial number reference

The PIN plate is riveted to the right-hand side of the cab on the lower frame, typically just behind the front idler or beneath the operator's window. Read the first three characters of the 17-character ISO PIN (positions 4–6) to identify the engine family and configuration variant.

PrefixIdentifies
3D72-2GEngine Model

Frequently asked questions

What engine does the Komatsu 3D72-2G (S/N 02519-UP) use?

The Komatsu 3D72-2G is the engine model itself, a diesel engine powering the PC07-2 mini excavator. It is part of the 3D72 series, distinct from the 3D72-2F and 3D72-2GA variants.

What is the operating weight of the machine powered by this engine?

The operating weight varies by configuration/series. The PC07-2 mini excavator typically falls in the compact class, with weights generally under 20,000 lbs, but exact figures vary by track shoe width and attachment package.

What replaced the Komatsu 3D72-2G engine?

The 3D72-2G engine was succeeded by newer Komatsu engine generations (such as the SAA6D107E series in larger machines) and later iterations of the PC07 series excavators. Specific successor engine model for the PC07-2 is not documented in the available sources.

What 3D72-2G(S/N 02519-UP) owners discuss

What engine powers the Komatsu 3D72-2G(S/N 02519-UP) and what are its known quirks?
The Komatsu 3D72-2G engine is a three-cylinder diesel unit. It is mechanically identical to the Yanmar 3TNA72. Common quirks include sensitivity to fuel quality; contamination or extended service intervals accelerate injector wear. Owners report that the engine is robust but requires strict adherence to air and fuel filter intervals to prevent power loss under load. The engine is known for efficient fuel consumption but can suffer from loping or rough idle if the governor or fuel delivery components are worn or if air enters the fuel supply. Verification: The engine model is confirmed by service manuals linking the 3D72-2 series to machines like the PC05-5. The cross-reference to the Yanmar 3TNA72 is documented in owner forums discussing parts availability. No specific horsepower or torque figures are provided in the source text for this exact serial range.
What are the typical hydraulic behaviors and common failure modes for this machine type?
Hydraulic systems in this class of Komatsu excavator are known for smooth operation and fuel efficiency. A common diagnostic pattern is weakness when hot; as oil warms and viscosity drops, internal leakage in the main pump, control valve, or cylinders becomes apparent. If all functions slow simultaneously, check the hydraulic oil level, filter condition, and engine RPM. If only one function is slow, investigate the specific cylinder, control valve spool, or load-holding valve. The main safety valve is critical; grinding or repairing it can resolve slow heating or pressure issues. Verification: Hydraulic troubleshooting patterns are derived from general Komatsu excavator diagnostics. Specific fluid recommendations include Komatsu Hydraulic Oil (HO) or equivalent ISO VG46. No specific flow rates or pressures are provided in the source text.
What undercarriage and wear patterns are typical for this machine?
Undercarriage components such as track pads, bushings, and bearings are subject to significant wear. Worn bushings lead to noise and vibration, while worn bearings can cause premature track failure. Track tension must be monitored regularly; repeated loosening often indicates adjuster or component wear. Mud or debris packed into the undercarriage can cause uneven travel speed or pulling to one side. Mechanical resistance from track-chain condition and roller wear should be checked before diagnosing hydraulic travel issues. Verification: Wear patterns are described in general used Komatsu excavator maintenance guides. No specific undercarriage dimensions or wear limits are provided in the source text.
What are the common electrical and sensor issues reported by owners?
Komatsu excavators rely heavily on electronic control systems. A single faulty sensor or unstable power supply can trigger multiple warning signals. Owners report intermittent starting, dashboard failure, or random shutdowns. Common electrical checks include battery state of charge, terminal condition, engine/chassis grounds, and main starter cable integrity. Voltage collapse under load during starting indicates a weak battery rather than a starter fault. Multiple fault codes often point to battery, ground, or connector issues. Verification: Electrical issues are described in general Komatsu troubleshooting guides. No specific sensor types or voltage values are provided in the source text.
What should be checked when buying a used Komatsu 3D72-2G(S/N 02519-UP)?
Verify the exact serial number to confirm the engine model and configuration, as specs vary by serial range. Check the cooling system for blockages in the radiator, hydraulic oil cooler, and charge-air cooler, as material packed between heat exchangers is common. Inspect the hydraulic system for leaks, worn seals, and proper fluid levels. Test the engine under load to check for power loss, overheating, or loping. Inspect the undercarriage for track tension, roller condition, and bushing wear. Check the battery and electrical connections for corrosion or loose grounds. Verify the operation of the main safety valve and swing brake. Note: The Komatsu line is noted for poor resale value if major components like the pump or engine fail, so thorough inspection is critical. Verification: Buying advice is synthesized from general used Komatsu excavator guides and forum discussions on resale value and common failures. No specific price or valuation data is provided in the source text.
What fluids and specifications are recommended for this engine and machine?
Komatsu recommends using Komatsu Genuine fluids that meet Komatsu Engineering Standards. For the engine, use Komatsu Diesel Engine Oil (EO) or equivalent. For the hydraulic system, use Komatsu Hydraulic Oil (HO) or equivalent ISO VG46. For the cooling system, use Super Coolant AF-NAC. Axle oil should be Komatsu Axle Oil (AXO) or equivalent SAE 80W-90. Powertrain oil should be Komatsu Powertrain Oil (TO) or equivalent. Verification: Fluid specifications are derived from Komatsu fluid guides and lubricant recommendations. No specific capacities or part numbers are provided in the source text.
What safety-critical fixes require dealer verification?
Safety-critical systems include the swing brake, travel motors, and final drives. If the upper structure drifts or will not hold position, the swing brake or mechanical play must be inspected. If the machine pulls to one side or travels at different speeds, the travel circuit and final drives must be checked. Grinding or repairing the main safety valve is critical for smooth hydraulic operation. Have your dealer verify the exact serial number configuration and perform pressure tests on the hydraulic and travel circuits to ensure safe operation. Verification: Safety notes are derived from general Komatsu troubleshooting and maintenance guidelines. No specific torque values or pressure settings are provided in the source text.

Compiled from owner and technician discussions across the industry — experiences vary by serial range and machine history.

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