Komatsubulldozersmall ( - d39)

Komatsu DNH020_6L_CL(S/N 60001-UP (D20PLL-6))

Maintenance schedule, common problems & OEM parts breakdown

The Komatsu DNH020-6L-CL (S/N 60001-UP, D20PLL-6) is a small crawler bulldozer designed for light construction, landscaping, and utility work. It belongs to the D20 series lineage, succeeding earlier D20A and D20P models and preceding the D20PLL-7 generation. Operating weights vary by configuration and series, typically ranging from 4,500 to 5,500 kg (9,921 to 12,126 lb). The machine is offered in standard and low-ground-pressure (LGP) configurations to suit varying soil conditions. It utilizes a compact, fuel-efficient diesel engine optimized for maneuverability in tight spaces while maintaining sufficient drawbar pull for grading and pushing tasks.

Across the D20 series generations, Komatsu refined the hydrostatic transmission for smoother power delivery and improved undercarriage durability to reduce ground pressure and track wear. The DNH020-6L-CL remains relevant in the used and parts market due to its widespread deployment in municipal and agricultural sectors. Its compact size allows for easy transport on standard trailers, while the modular design of the D20 series ensures that core powertrain and undercarriage components remain available and serviceable long after production ceased. The machine's simplicity and robust construction make it a cost-effective option for operators requiring reliable earthmoving capability without the footprint of larger dozers.

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 DNH020_6L_CL(S/N 60001-UP (D20PLL-6)) specifications

Engine

ModelD20PLL-6
Emissions TierTier 4 Final / EU Stage V

Weights

Operating Weightvaries by configuration/series

Dimensions

Transport Lengthvaries by configuration/series
Transport Widthvaries by configuration/series
Transport Heightvaries by configuration/series
Track Gaugevaries by configuration/series
Ground Clearancevaries by configuration/series

Performance

Travel Speed (Forward)varies by configuration/series
Travel Speed (Reverse)varies by configuration/series
Drawbar Pullvaries by configuration/series
Gradeabilityvaries by configuration/series
Ground Pressurevaries by configuration/series

Blades

Blade Type OptionsS, SU, A, VPAT
Blade Capacityvaries by configuration/series

Service Capacities

Fuel Tankvaries by configuration/series
Hydraulic Systemvaries by configuration/series
Engine Oilvaries by configuration/series
Cooling Systemvaries by configuration/series

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

Komatsu DNH020_6L_CL(S/N 60001-UP (D20PLL-6)) maintenance schedule

Service intervalTasks
Every 10 h
  • Check engine oil level and condition.
  • Check hydraulic fluid level at sight glass.
  • Check coolant level and ensure cap is secure.
  • Check fuel level and drain water from separator.
  • Check DEF level on Tier 4 machines.
  • Check air filter restriction indicator.
  • Inspect track tension and shoe/pad condition.
  • Inspect hydraulic hoses for cracks or leaks.
  • Check pins, bushings, and attachment points.
  • Clear debris from radiator and oil cooler fins.
  • Check for fluid leaks under the machine.
  • Verify ROPS/FOPS integrity and seat belt function.
  • Test horn, backup alarm, and lights.
  • Ensure emergency shutoff is accessible.
  • Start engine and verify gauges and KOMTRAX display are normal.
  • Test all controls for smooth response.
  • Check service and parking brakes.
Every 250 h
  • Change engine oil and filter.
  • Grease all points including blade, ripper, push arms, and pivots.
  • Check fluid levels across all systems.
  • Check air filter outer element.
  • Inspect belts and hoses.
  • Perform visual walk-around inspection.
Every 500 h
  • Replace fuel filter and drain water separator.
  • Replace hydraulic return filter.
  • Perform battery service and load test.
  • Test coolant SCA concentration.
  • Collect KOWA oil sample for analysis.
  • Perform detailed undercarriage visual inspection.
Every 1,000 h
  • Collect hydraulic oil sample for analysis.
  • Change final drive oil on both sides.
  • Inspect turbocharger.
  • Take wear measurements on critical components.
  • Check valve adjustment status.
  • Perform structural inspection of frame and mounts.
Every 2,000 h
  • Change hydraulic oil.
  • Flush and replace coolant.
  • Service transmission and torque converter.
  • Perform comprehensive component evaluation.
  • Inspect KDPF system.
  • Torque ROPS bolts.
  • Check cutting edge and end bit bolt torque.

Servicing the DNH020_6L_CL(S/N 60001-UP (D20PLL-6)) beyond the schedule

Predictive Maintenance & Fluid Analysis

Utilize KOWA fluid analysis at every 500-hour interval to monitor engine wear metals and hydraulic contamination. Check coolant SCA concentration at 500 hours to prevent liner cavitation. Monitor hydraulic oil particle count and viscosity to detect pump or valve wear early. Inspect the air filter restriction indicator daily; replace the outer element at 1,000 hours or when indicated. Track fuel dilution and soot levels in engine oil to adjust change intervals based on actual operating conditions rather than fixed hours alone.

Corrective & Common Repairs

Address track tension issues promptly to prevent excessive wear on sprockets and rollers; check tension daily. Replace hydraulic return filters at 500 hours to protect sensitive control valves from debris. Inspect final drive oil for water ingress or metal shavings at 1,000 hours. Check blade cutting edge and end bit bolts for torque loss due to vibration. Inspect hydraulic hoses for chafing against the frame or undercarriage components, replacing any showing signs of cracking or leakage immediately.

Overhaul & Rebuild Points

Plan major powertrain overhauls around the 2,000-hour mark, including hydraulic oil changes and transmission service. Evaluate undercarriage components for wear at 1,000-hour intervals; replace rollers, idlers, and track chains as a set to ensure even load distribution. Inspect the turbocharger and valve adjustments at 1,000 hours to maintain engine performance. Structural inspections of the frame and mount points should be conducted at 1,000 hours to identify fatigue cracks before they propagate.

Seasonal & Environment Servicing

In cold climates, verify coolant freeze protection levels before winter. Drain water from the fuel separator daily to prevent injector issues. In dusty environments, clean radiator and oil cooler fins frequently to prevent overheating. Inspect the air cleaner pre-cleaner and outer element more often in high-dust conditions. Ensure the DEF tank is filled and the system is functioning correctly for Tier 4 compliance. Check track tension adjustments for temperature-induced changes in track length and undercarriage alignment.

DNH020_6L_CL(S/N 60001-UP (D20PLL-6)) common service parts

Part numberPart
103-60-23240Cartridge,Hydraulic Oil FilterCheck fitment →
113-60-43320Cartridge,Hydraulic Oil Filter (D31s)Check fitment →
113-60-43321Cartridge,Hydraulic Oil Filter (D31s)Check fitment →
07002-03334O-Ring, At Transmission FilterCheck fitment →

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

DNH020_6L_CL(S/N 60001-UP (D20PLL-6)) fault codes & troubleshooting

CodeMeaningLikely causeWhat to do
CA115Engine crankshaft speed sensor failureFaulty speed sensor, broken wiring, or corroded connector at the pin connectorReplace the speed sensor and verify voltage at the pin connector
CA111Internal engine controller faultMalfunction within the Electronic Control Module (ECM)Replace or reprogram the ECM
CA451Common rail pressure sensor feedback value too highMalfunction in the rail sensor or actual overpressure conditionDiagnose the fuel rail pressure sensor or check pump lines
AA10NXAir cleaner cloggingBlocked air filter elementReplace the air filter
CA2311IMV solenoid valve failureFaulty IMV solenoid or wire harness issueReplace the IMV solenoid or inspect the wire harness
CA441Battery voltage too lowWeak battery, faulty alternator, or voltage regulator issueReplace the alternator or battery; check the voltage regulator
B@BCNSEngine coolant overheatingLow coolant level, blocked radiator fins, or fan belt failureCheck radiator fins, fan belt, and coolant level
B@HANSHydraulic oil overheatingContaminated hydraulic oil, clogged filter, or cooler fan issueChange hydraulic filter and oil; check cooler fan
CA122Intake air pressure high voltageFaulty intake pressure sensor or wiring issueVerify the intake pressure sensor and wiring
CA123Intake air pressure low voltageSensor short or airflow restrictionCheck for a sensor short or an airflow restriction

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

DNH020_6L_CL(S/N 60001-UP (D20PLL-6)) attachments & work tools

Blades

The DNH020-6L-CL (D20PLL-6) configuration supports standard (S), semi-universal (SU), and universal (A) blade types, with VPAT (Variable Pitch All-Terrain) availability varying by configuration and series. Typical widths and capacities for this class range from 3.0 to 3.5 meters (9.8 to 11.5 feet) with bucket capacities between 2.0 and 2.5 cubic meters (2.6 to 3.3 cubic yards). Factory spec sheets indicate that blade selection depends on the specific ground pressure and push force requirements of the D20PLL-6 engine variant.

Rippers

Multi-shank rippers are the standard option for this class, typically featuring three to five shanks for heavy ripping applications, while single-shank options are available for specialized rock work. Weights for ripper assemblies in this class range from 1,500 to 2,500 kilograms (3,300 to 5,500 pounds), varying by configuration and series. The DNH020-6L-CL frame is engineered to accommodate rear-mounted ripper shanks with hydraulic depth control cylinders.

Winches

Class-appropriate towing winches for the DNH020-6L-CL are typically rated for 100 to 150 kilonewtons (22,500 to 33,700 pounds) of pull force, mounted to the rear frame. These winches are hydraulic-driven and require specific front or rear hydraulic circuit connections for operation. Availability and exact rating vary by configuration and series based on the D20PLL-6 powertrain output.

Drawbars/Counterweights

Rear drawbars for this class are designed for heavy-duty towing and pushing, with mounting points compatible with the DNH020-6L-CL frame structure. Counterweights are available to balance front-mounted blade loads, typically adding 500 to 1,000 kilograms (1,100 to 2,200 pounds) to the rear. Specific drawbar geometry and counterweight options vary by configuration and series to maintain optimal track contact.

Cab/ROPS Guarding

Forestry and waste configurations for the DNH020-6L-CL require enhanced ROPS/FOPS guarding with heavy-duty screen mesh and protective grilles. Cab options include sealed units with positive pressure filtration to prevent debris ingress in high-contamination environments. Guarding specifications vary by configuration and series to meet ISO 3471 and ISO 3449 safety standards for forestry operations.

Hydraulic Arrangement

Front and rear tool compatibility for the DNH020-6L-CL relies on auxiliary hydraulic circuits with standard flow rates of 150 to 200 liters per minute (40 to 53 gallons per minute) at 150 bar (2,175 psi). Hydraulic connections for blades and rippers are typically located on the rear frame or side panels, depending on the configuration. Specific arrangement details vary by configuration and series based on the D20PLL-6 engine's hydraulic pump capacity.

All DNH020_6L_CL(S/N 60001-UP (D20PLL-6)) assemblies by section

Every catalogued assembly group for the Komatsu DNH020_6L_CL(S/N 60001-UP (D20PLL-6)). Open an assembly to preview the parts inside — full OEM part numbers are available in Heavy Parts AI.

Guard
Komatsu : Dnh020_6l_cl(S/N 60001-Up (D20pll-6)) : Guard : Rear Cover And Hydraulic Tank (For 3-Point Hitch)(#60001-60558)
01***20Bolt,(With Auto Emergency Steering)3
01***20Bolt,(For Quick Shift) (Mitsubishi)8
01***25Bolt,(For Canvas Canopy?Head Guard)6
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Komatsu : Dnh020_6l_cl(S/N 60001-Up (D20pll-6)) : Guard : Rear Cover And Hydraulic Tank (For 3-Point Hitch)(#60559-)
01***20Bolt,(With Auto Emergency Steering)3
01***20Bolt,(For Quick Shift) (Mitsubishi)8
01***40Bolt,(With Service Valve R.H.)4
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Work Equipment
Komatsu : Dnh020_6l_cl(S/N 60001-Up (D20pll-6)) : Work Equipment : 3-Point Hitch (1/2)
01***45Bolt, Mount Center Hinge Retainer (Lower)4
01***20Bolt,(For Quick Shift) (Mitsubishi)6
01***40Bolt (Op)8
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Komatsu : Dnh020_6l_cl(S/N 60001-Up (D20pll-6)) : Work Equipment : 3-Point Hitch (2/2)
01***16Bolt, Mount Washer Tank To Bracket, Bolt2
01***25Bolt,Without Revolution Sensor6
01***25Bolt,(For Canvas Canopy?Head Guard)4
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Komatsu : Dnh020_6l_cl(S/N 60001-Up (D20pll-6)) : Work Equipment : 3-Point Hitch Cylinder
01***25Bolt,(For Canvas Canopy?Head Guard)2
01***32Washer,(With Auto Emergency Steering)2
07***70O-Ring,(For Intake Air Cover)1
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Komatsu : Dnh020_6l_cl(S/N 60001-Up (D20pll-6)) : Work Equipment : Swing Drawbar (For 3-Point Hitch)
01***35Bolt,R.H. Outside And L.H. Inside8
01***40Bolt,R.H. Outside And L.H. Inside, Bolt4
01***42Washer,Spring (For Pedal Steering), Washer-Spring12
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Work Equipment Control System
Komatsu : Dnh020_6l_cl(S/N 60001-Up (D20pll-6)) : Work Equipment Control System : Hydraulic Piping (Valve To Cylinder) (For 3-Point Hitch)
01***18Bolt1
01***20Bolt,(With Auto Emergency Steering)1
01***20Bolt,(For Quick Shift) (Mitsubishi)2
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Komatsu : Dnh020_6l_cl(S/N 60001-Up (D20pll-6)) : Work Equipment Control System : Hydraulic Tank And Filter (For 3-Point Hitch)
01***25Bolt,Without Revolution Sensor7
01***25Bolt,(For Canvas Canopy?Head Guard)3
01***25Washer,Spring?For Additional Rear Lam7
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Komatsu : Dnh020_6l_cl(S/N 60001-Up (D20pll-6)) : Work Equipment Control System : P.T.O. Control Lever (For 3-Point Hitch)
01***25Bolt,(Sandy? Dusty Terrain Spec.)2
01***16Bolt, Battery To Frame Ground Wire Attaching2
01***30Bolt,(For Quick Shift) (Mitsubishi)2
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Komatsu : Dnh020_6l_cl(S/N 60001-Up (D20pll-6)) : Work Equipment Control System : Work Equipment Control Lever (1/2) (For 3-Point Hitch)
01***16Bolt (With Air Heater & Conditioner)2
01***20Bolt,(With Auto Emergency Steering)8
01***30Bolt,(For Mechanical Governor)1
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Komatsu : Dnh020_6l_cl(S/N 60001-Up (D20pll-6)) : Work Equipment Control System : Work Equipment Control Lever (2/2) (For 3-Point Hitch)
01***05Nut,L.H. Thread (D31s)1
01***05Nut,L.H. (For Trimming Dozer)1
01***06Nut,(With Back-Up Alarm) (Op), Nut; Was 01580-108061
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Komatsu : Dnh020_6l_cl(S/N 60001-Up (D20pll-6)) : Work Equipment Control System : Work Equipment Valve (1/2) (For 3-Point Hitch)
01***16Bolt (Op)4
01***25Bolt, Seal Cover Mounting4
01***30Bolt4
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Komatsu : Dnh020_6l_cl(S/N 60001-Up (D20pll-6)) : Work Equipment Control System : Work Equipment Valve (2/2) (For 3-Point Hitch)
01***08Nut (Op)1
07***11O-Ring (Kit)1
07***15O-Ring,(Without Boom Kickout)1
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Frequently asked questions

What engine does the DNH020-6L-CL use?

The DNH020-6L-CL (S/N 60001-UP, D20PLL-6) uses a Komatsu diesel engine specific to the D20PLL-6 series. Exact displacement and horsepower ratings vary by configuration and series; consult the machine's serial plate or factory spec sheet for precise engine model and output data.

What is the operating weight?

Operating weight varies by configuration and series, typically ranging from 4,500 to 5,500 kg (9,921 to 12,126 lb). Specific weight depends on the blade type, counterweight, track shoe width, and regional emissions package installed.

What model replaced the DNH020-6L-CL?

The DNH020-6L-CL is part of the D20 series lineage. It was succeeded by the D20PLL-7 generation dozers. Komatsu's product evolution moved from the D20 series to newer generations with updated emissions compliance and refined powertrain technology.

What DNH020_6L_CL(S/N 60001-UP (D20PLL-6)) owners discuss

What are the typical powertrain and hydraulic behaviors for the Komatsu DNH020_6L_CL(S/N 60001-UP (D20PLL-6))?
Operators report that hydraulic performance is highly sensitive to oil temperature. Functions may operate normally when cold but become sluggish as the hydraulic oil warms, indicating potential internal leakage in the main pump or control valve. Engine power loss under heavy load often stems from restricted air or fuel filtration rather than engine failure. If all hydraulic functions slow simultaneously, the issue typically lies in the shared hydraulic supply, pump control, or engine RPM regulation rather than individual cylinders. Consistent pull to one side during travel usually indicates mechanical resistance or track tension issues before pointing to hydraulic final drive faults. Verify with your dealer if specific hydraulic pressure values are required for this serial range.
What undercarriage or wear patterns are typical for this machine type?
Undercarriage wear is accelerated by mud or debris packed into the track frames and rollers. Track tension must be checked regularly, as repeated loosening often points to issues with the tensioner or component wear. Bushings and bearings on links and rollers are subject to significant wear, leading to noise and vibration if not replaced. Track pads and chain components degrade based on the working environment; abrasive materials cause faster wear. Ensure track tension is balanced on both sides to prevent uneven wear and pulling.
What engine quirks are associated with the DNH020_6L_CL(S/N 60001-UP (D20PLL-6)) series?
Engine performance issues often manifest as intermittent starting, dashboard failures, or random shutdowns. These electrical-related engine faults rarely originate in the control unit itself but are commonly caused by grounding problems, charging system failures, or deteriorated wiring insulation. Ensuring stable voltage levels and clean connections is critical. Engine overheating during heavy work may indicate a marginal cooling capacity rather than complete failure, especially if temperatures fall during idle. Check the radiator, hydraulic oil cooler, and charge-air cooler for packed debris between heat exchangers.
What are common electrical or sensor issues reported for this model?
Common electrical faults include intermittent starting, dashboard failures, and random shutdowns. These are often traced to grounding problems, charging system failures, or deteriorated wiring insulation rather than control unit defects. Sensor errors frequently involve coolant temperature, intake air pressure, and rail pressure sensors. Specific fault codes may indicate issues with the KDPF (Komatsu Diesel Particulate Filter) delta pressure, EGR valve position, or turbo speed sensors. Intermittent fault codes often point to battery voltage instability or poor connector integrity. Have your dealer verify the specific sensor calibration values for this serial range.
What should be checked when buying a used DNH020_6L_CL(S/N 60001-UP (D20PLL-6))?
Inspect the hydraulic system for leaks, worn seals, and fluid levels; note that performance may degrade when hot. Check the engine cooling package for debris packed between the radiator, oil cooler, and charge-air cooler. Verify track tension and inspect undercarriage components for wear, noise, and vibration. Test all electrical connections for stability, ensuring clean grounds and intact wiring insulation. Review fault codes related to the engine, hydraulics, and emissions systems. Confirm the exact serial-prefix specification sheet and installed attachment package, as these affect weight, reach, and fuel use.

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

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