Komatsuengine(no series)

Komatsu S6D105-1V(S/N 61676-UP)

Maintenance schedule, common problems & OEM parts breakdown

The Komatsu S6D105-1V engine (S/N 61676-UP) is a six-cylinder, turbocharged, direct-injection diesel powerplant used in the Komatsu 6D105 series family. It powers mid-size crawler excavators such as the PC200 and PC220, as well as wheel loaders like the WA300 and WA320, and motor graders including the GD500R and GD505. Operating weights for these machines typically range from 19,000 to 25,000 lb (8,600 to 11,300 kg). The S6D105-1V succeeded earlier S6D105-1 variants and was later replaced by the SAA6D107E-1 in newer Tier 4/Stage IIIa generations.

Across the 6D105 series generations, the primary changes involved the transition from mechanical fuel systems to electronic control units and the integration of emissions aftertreatment systems like the KDPF and SCR. The S6D105-1V remains significant in the used and parts market because it serves as the core powertrain for a massive installed base of PC200 and PC220 excavators. Its widespread use ensures high availability of aftermarket components and a deep knowledge base for rebuild, making it a critical reference point for fleet maintenance and resale valuation.

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 S6D105-1V(S/N 61676-UP) specifications

Engine

ModelS6D105-1V
Series6D105 Series
Cylinders6
Displacement6.5 L (396 cu. in.)
AspirationTurbocharged
Fuel SystemDirect injection, mechanical fuel system
Gross Power170 hp (127 kW)
Torque745 N·m (550 lb-ft)
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
Dig DepthNot documented for this exact serial range — verify with your dealer
Bucket CapacityNot documented for this exact serial range — verify with your dealer

Service capacities (summary)

Engine Oil Refill CapacityVaries by configuration/series (refer to engine model specific table in Operation and Maintenance Manual)
Cooling System CapacityVaries by configuration/series (refer to engine model specific table in Operation and Maintenance Manual)
Hydraulic System CapacityNot documented for this exact serial range — verify with your dealer
Fuel Tank CapacityNot 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 S6D105-1V(S/N 61676-UP) 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.
Every 250 h
  • Change engine oil and filter.
  • Grease all points including boom, stick, bucket, and swing bearing.
  • Check fluid levels.
  • Check air filter element.
  • Inspect belts and hoses.
  • Perform visual walk-around inspection.
Every 500 h
  • Replace fuel filter.
  • Replace hydraulic return filter.
  • Perform battery service and load test.
  • Test coolant SCA concentration.
  • Collect KOWA oil sample.
  • Perform detailed undercarriage inspection.
Every 1,000 h
  • Collect hydraulic oil sample.
  • Change final drive oil on both sides.
  • Inspect turbocharger.
  • Take wear measurements.
  • Check valve adjustment.
  • Perform structural inspection.
Every 2,000 h
  • Change hydraulic system oil.
  • Flush and replace coolant.
  • Service transmission.
  • Perform comprehensive component evaluation.
  • Check KDPF status.
  • Inspect and replace worn belts, hoses, and clamps.

Servicing the S6D105-1V(S/N 61676-UP) beyond the schedule

Predictive Maintenance & Fluid Analysis

Utilize KOWA fluid analysis at every 500-hour interval to monitor engine wear metals (iron, copper, lead, aluminum) and contaminants. Track hydraulic particle count and viscosity changes to predict pump and valve failures. Monitor coolant pH and SCA concentration to prevent liner cavitation. Use KOMTRAX telematics to correlate load frequency and fuel burn with oil oxidation levels. Early detection of fuel dilution or coolant ingress in the S6D105-1V prevents catastrophic bearing damage and extends service intervals safely.

Corrective & Common Repairs

Address S6D105-1V turbocharger boost leaks and injector seal failures promptly to maintain torque output. Replace worn turbocharger shafts and bearings if oil consumption exceeds limits. Inspect and replace cracked high-pressure fuel lines common in older mechanical systems. Check for coolant leaks at the water pump seal and thermostat housing. Replace worn injector O-rings to prevent compression loss and black smoke. Verify electrical connector integrity on the ECU and sensor harnesses to avoid erratic idle or shutdown codes.

Overhaul & Rebuild Points

Plan the S6D105-1V inframe overhaul at approximately 10,000 to 12,000 hours or when compression drops below specification. Replace piston rings, liners, and bearings during the inframe stage. Perform a full teardown overhaul at 15,000 to 20,000 hours, replacing the crankshaft, camshaft, and cylinder head gaskets. Inspect the turbocharger housing for cracks and replace if necessary. Rebuild the fuel injection pump and injectors to restore precise fuel delivery and combustion efficiency.

Seasonal & Environment Servicing

In cold climates, use Komatsu EO or equivalent low-viscosity diesel engine oil to ensure cold-start reliability. Install block heaters and coolant warmers to prevent gel in fuel filters and reduce wear during startup. In dusty environments, service the air filter more frequently and check the restriction indicator daily. In high-humidity areas, drain the fuel water separator more often to prevent microbial growth. Verify DEF tank heater operation in freezing conditions to prevent crystallization and injection system blockages.

S6D105-1V(S/N 61676-UP) common service parts

Part numberPart
07281-00197Clamp,(With Pre-Fuel Filter)Check fitment →
600-311-8291Cartridge,Fuel FilterCheck fitment →
600-311-9100Fuel Filter Ass'YCheck fitment →
6138-71-6100Fuel Filter Ass'Y,(See Fig.0419)Check fitment →
6136-71-6120Cartridge,Engine Fuel FilterCheck fitment →

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

S6D105-1V(S/N 61676-UP) fault codes & troubleshooting

CodeMeaningLikely causeWhat to do
CA115Engine crankshaft speed sensor and backup speed sensor failureFaulty crankshaft speed sensor, broken wiring harness, or corroded connector at the sensor pinInspect the speed sensor and wiring harness; replace the sensor if voltage is abnormal at the connector
CA111Internal engine controller faultElectronic Control Module (ECM) internal failure or critical software errorReplace or reprogram the ECM
CA451Common rail pressure sensor feedback value too highMalfunctioning rail pressure sensor, actual overpressure condition, or wiring shortDiagnose the fuel rail pressure sensor and check pump lines for blockage or leakage
CA452Common rail pressure sensor feedback value too lowFuel rail pressure sensor failure, low fuel supply pressure, or open circuitCheck the fuel supply pump and pressure sensor circuit; verify fuel delivery
CA234Engine overspeedThrottle calibration error, excessive engine load cycle, or operator misuseVerify throttle calibration and inspect the engine load cycle for anomalies
CA122Intake air pressure sensor feedback voltage too highFaulty intake pressure sensor, shorted wiring, or sensor signal errorVerify the intake pressure sensor operation and inspect the wiring harness for shorts
CA123Intake air pressure sensor feedback voltage too lowSensor short circuit, airflow restriction, or wiring open circuitCheck for a sensor short or an airflow restriction in the intake system
CA153Intake air temperature sensor feedback voltage too highFaulty Intake Air Temperature (IAT) sensor or wiring issueReplace or test the IAT sensor for proper resistance and voltage output
CA441Battery voltage too lowWeak battery, failing alternator, or loose connectionsReplace the battery or alternator; check the voltage regulator and connections
CA442Battery voltage too highFailing voltage regulator or alternator overchargingReplace the alternator or battery; check the voltage regulator operation

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

S6D105-1V(S/N 61676-UP) attachments & work tools

Crawler Dozer Blade Systems

The S6D105-1V engine is installed in D20, D21, D31, D40, and D41 crawler dozers. These machines utilize standard dozer blades and ripper attachments. Factory guarding options include ROPS/FOPS cabs and side guards for the undercarriage. Specific blade capacities vary by configuration and series.

Crawler Excavator Work Tools

The engine powers the PC200 and PC220 series excavators (PC200-1/2/3, PC220-1/2/3). Typical work tools include digging buckets, grading buckets, and rock buckets. Mounting systems utilize standard excavator quick couplers or pin-on connections. Hydraulic kit arrangements vary by configuration/series depending on the specific tool flow requirements.

Wheel Loader Attachments

The engine is used in WA300-1, WA320-1, and WA350-1 wheel loaders. Standard work tools include general purpose buckets, light material buckets, and rock buckets. Coupler systems are typically pin-on or quick-attach mechanisms. Factory configurations include varying bucket capacities based on the specific loader model and series.

Motor Grader Blades

The engine is fitted to GD405A-1, GD500R-2, GD505A-2, GD505R-2, GD521A-1, GD521R-1, GD523A-1, GD611A-1, and GD661A-1 motor graders. Work tools consist of moldboards, angle blades, and scarifiers. Mounting is integrated into the grader frame. Guarding options include operator protection structures.

Wheeled Excavator Tools

The engine is installed in the PW400MH-6 wheeled excavator. Work tools include standard digging buckets and hydraulic breakers. Hydraulic arrangements must match the machine's flow capacity. Mounting uses standard quick-attach or pin-on systems.

Industrial Engine Applications

The S6D105-1V is used in EG100-2, EG100S-2, and EG125-1/EG125S-1 industrial engines. These units do not use interchangeable work tools but are configured for power generation or pumping applications. Factory options include varying exhaust configurations and mounting bases.

All S6D105-1V(S/N 61676-UP) assemblies by section

Every catalogued assembly group for the Komatsu S6D105-1V(S/N 61676-UP). Open an assembly to preview the parts inside — full OEM part numbers are available in Heavy Parts AI.

Cooling System
Komatsu : S6d105-1v(S/N 61676-Up) : Cooling System : Corrosion Resistor And Piping
01***25Bolt,(Sandy? Dusty Terrain Spec.)4
01***29Washer,Spring (Cold Weather Spec.)4
01***30Washer,Spring(Sandy?Dusty Terrain S.)4
See all parts with full part numbers in Heavy Parts AI →
Komatsu : S6d105-1v(S/N 61676-Up) : Cooling System : Water Pump And Cooling Fan (Water Pump With Non Hardening Pulley)
01***16Bolt,(For Slag Handling)2
01***30Bolt,(Cold Terrain Spec.)3
01***30Bolt,(For France Noise Suppression)6
See all parts with full part numbers in Heavy Parts AI →
Cylinder Block
Komatsu : S6d105-1v(S/N 61676-Up) : Cylinder Block : Camshaft And Tappet
01***25Bolt,(Without Auto Priming System)2
01***25Washer,Spring?(Sandy And Dusty Spec.)2
01***16Washer,(For Shipping)2
See all parts with full part numbers in Heavy Parts AI →
Komatsu : S6d105-1v(S/N 61676-Up) : Cylinder Block : Crankshaft
01***25Bolt - Rear Guard Mounting6
01***36Washer,Radio Controlled Slag Handling6
61***11Bolt,Nylock (K2)1
See all parts with full part numbers in Heavy Parts AI →
Komatsu : S6d105-1v(S/N 61676-Up) : Cylinder Block : Cylinder Block
01***30Bolt,(For France Noise Suppression)3
01***50Bolt1
01***30Washer,Spring(Sandy?Dusty Terrain S.)4
See all parts with full part numbers in Heavy Parts AI →
Komatsu : S6d105-1v(S/N 61676-Up) : Cylinder Block : Flywheel And Flywheel Housing
01***40Bolt,(Dust And Dirt Protection)9
01***60Bolt, Trunnion Cap2
01***35Screw6
See all parts with full part numbers in Heavy Parts AI →
Komatsu : S6d105-1v(S/N 61676-Up) : Cylinder Block : Front Cover And Gear
01***22Bolt,(Cold Terrain Spec.)4
01***25Bolt,(Without Auto Priming System)4
01***60Bolt,(Without Alternator Bracket)8
See all parts with full part numbers in Heavy Parts AI →
Komatsu : S6d105-1v(S/N 61676-Up) : Cylinder Block : Oil Pan(#61676-63902)
01***22Bolt,(Cold Terrain Spec.)29
01***25Bolt,(Without Auto Priming System)8
01***30Bolt,(Cold Terrain Spec.)3
See all parts with full part numbers in Heavy Parts AI →
Komatsu : S6d105-1v(S/N 61676-Up) : Cylinder Block : Oil Pan(#63903-)
01***22Bolt,(Cold Terrain Spec.)29
01***25Bolt,(Without Auto Priming System)8
01***30Bolt,(Cold Terrain Spec.)1
See all parts with full part numbers in Heavy Parts AI →
Komatsu : S6d105-1v(S/N 61676-Up) : Cylinder Block : Piston And Connecting Rod
04***18Ring, Retaining2
61***40Crank Pin Metal A6
61***00Connecting Rod Ass'Y,(B)6
See all parts with full part numbers in Heavy Parts AI →
Cylinder Head
Komatsu : S6d105-1v(S/N 61676-Up) : Cylinder Head : Air Cleaner
01***08Nut,R.H. Thread8
01***30Washer,Spring(Sandy?Dusty Terrain S.)8
01***16Washer,Radio Controlled Slag Handling8
See all parts with full part numbers in Heavy Parts AI →
Komatsu : S6d105-1v(S/N 61676-Up) : Cylinder Head : Air Intake Manifold And Connection
01***20Bolt2
01***50Bolt,(For Trimming Dozer)2
01***65Bolt,(For Alternator Bracket Mount)10
See all parts with full part numbers in Heavy Parts AI →
Komatsu : S6d105-1v(S/N 61676-Up) : Cylinder Head : Cylinder Head
01***25Bolt,(Sandy? Dusty Terrain Spec.)2
01***30Washer,Spring(Sandy?Dusty Terrain S.)2
07***08Plug (Kit)7
See all parts with full part numbers in Heavy Parts AI →
Komatsu : S6d105-1v(S/N 61676-Up) : Cylinder Head : Cylinder Head Cover(#61676-79428)
01***25Washer,Spring?(Sandy And Dusty Spec.)2
02***22Bolt3
02***22Bolt2
See all parts with full part numbers in Heavy Parts AI →
Komatsu : S6d105-1v(S/N 61676-Up) : Cylinder Head : Cylinder Head Cover(#79429-)
07***23Clamp - Hose1
07***00Clip1
07***30Clip1
See all parts with full part numbers in Heavy Parts AI →
Komatsu : S6d105-1v(S/N 61676-Up) : Cylinder Head : Exhaust Manifold And Turbocharger
01***00Bolt (M10-1.50x100)12
01***32Washer,(With Auto Emergency Steering)1
02***38Bolt4
See all parts with full part numbers in Heavy Parts AI →
Komatsu : S6d105-1v(S/N 61676-Up) : Cylinder Head : Muffler
Komatsu : S6d105-1v(S/N 61676-Up) : Cylinder Head : Rocker Arm
01***80Bolt,(Shim 5 Pieces Over)2
01***06Nut, Regular Hexagon (M8-1.25)12
01***36Washer,Radio Controlled Slag Handling6
See all parts with full part numbers in Heavy Parts AI →
Komatsu : S6d105-1v(S/N 61676-Up) : Cylinder Head : Turbocharger (Except Japan)
61***00Turbocharger Ass'Y,(T04b-59)1
GA***00Clamp3
GA***01Bolt1
See all parts with full part numbers in Heavy Parts AI →
Electrical System
Komatsu : S6d105-1v(S/N 61676-Up) : Electrical System : Alternator (25a) (With Non Hardening Pulley)
60***60Alternator A. (25a),(With Non Hardening Pulley)1
KD***37Bearing,Ball? Front1
KD***72Slip Ring Ass'Y1
See all parts with full part numbers in Heavy Parts AI →
Komatsu : S6d105-1v(S/N 61676-Up) : Electrical System : Alternator And Mounting (25a) (Alternator With Non Hardening Pulley)
01***70Bolt2
01***25Bolt,(Sandy? Dusty Terrain Spec.)1
01***35Bolt, Mounting - Flywheel Housing End1
See all parts with full part numbers in Heavy Parts AI →
Komatsu : S6d105-1v(S/N 61676-Up) : Electrical System : Heater Signal And Heater Switch
60***70Switch,Air Intake Heater1
60***71Signal,Signal1
60***10Regulator Ass'Y1
See all parts with full part numbers in Heavy Parts AI →
Komatsu : S6d105-1v(S/N 61676-Up) : Electrical System : Starting Motor (5.5kw)(#61676-81586)
60***43Starting Motor A.,(5.5kw) (See Fig.0661)1
KD***10Clutch Ass'Y,Over Running1
KD***60Metal,Center1
See all parts with full part numbers in Heavy Parts AI →
Komatsu : S6d105-1v(S/N 61676-Up) : Electrical System : Starting Motor (5.5kw)(#81587-)
60***80Starting Motor Ass'Y,(5.5kw)1
KD***30Bracket,Center1
KD***50Clutch Ass'Y,Over Running1
See all parts with full part numbers in Heavy Parts AI →
Komatsu : S6d105-1v(S/N 61676-Up) : Electrical System : Starting Motor And Mounting (5.5kw)
01***35Bolt - Torque Converter Totransmission Mounting3
01***36Washer,Radio Controlled Slag Handling3
07***00O-Ring,(F4350-65a1 -5 )1
See all parts with full part numbers in Heavy Parts AI →
Engine Kit
Komatsu : S6d105-1v(S/N 61676-Up) : Engine Kit : Gasket Kit
07***70O-Ring,(For Intake Air Cover)1
07***00O-Ring,(F4350-65a1 -5 )1
07***45O-Ring,(F4320-61a0 -16 ), O-Ring; Was 07000-021451
See all parts with full part numbers in Heavy Parts AI →
Fuel System
Komatsu : S6d105-1v(S/N 61676-Up) : Fuel System : Additionl Fuel Filter
07***12Gasket,Mechanical Pump Piping2
60***91Cartridge,Fuel Filter1
60***00Fuel Filter Ass'Y1
See all parts with full part numbers in Heavy Parts AI →
Komatsu : S6d105-1v(S/N 61676-Up) : Fuel System : Fuel Filter And Piping
01***30Bolt,(For France Noise Suppression)4
01***30Washer,Spring(Sandy?Dusty Terrain S.)4
01***16Washer,Radio Controlled Slag Handling2
See all parts with full part numbers in Heavy Parts AI →
Komatsu : S6d105-1v(S/N 61676-Up) : Fuel System : Fuel Injection Pump (Coupling)
DK***00Bolt1
DK***00Washer,Lock2
DK***00Coupling,Cross1
See all parts with full part numbers in Heavy Parts AI →
Komatsu : S6d105-1v(S/N 61676-Up) : Fuel System : Fuel Injection Pump (Feed Pump)
DK***20Bolt, Joint1
DK***20Pump,Priming1
DK***20Housing1
See all parts with full part numbers in Heavy Parts AI →
Komatsu : S6d105-1v(S/N 61676-Up) : Fuel System : Fuel Injection Pump (Governor) (1/2)
Komatsu : S6d105-1v(S/N 61676-Up) : Fuel System : Fuel Injection Pump (Governor) (2/2)
DK***40Gasket,Air Compressor2
DK***00Nut,Cap1
DK***40Bolt2
See all parts with full part numbers in Heavy Parts AI →
Komatsu : S6d105-1v(S/N 61676-Up) : Fuel System : Fuel Injection Pump (Pump)
61***00Injection Pump Ass'Y1
DK***10Washer,Spring1
DK***30Bearing0
See all parts with full part numbers in Heavy Parts AI →
Komatsu : S6d105-1v(S/N 61676-Up) : Fuel System : Fuel Injection Pump And Piping
01***70Bolt4
01***35Bolt, Mounting - Flywheel Housing End4
01***25Bolt,(For Canvas Canopy?Head Guard)1
See all parts with full part numbers in Heavy Parts AI →
Komatsu : S6d105-1v(S/N 61676-Up) : Fuel System : Fuel Nozzle And Spill Pipe(#61376-)
01***55Bolt,(For Trimming Dozer)12
01***25Washer,Spring?(Sandy And Dusty Spec.)12
07***12Gasket,Mechanical Pump Piping2
See all parts with full part numbers in Heavy Parts AI →
Komatsu : S6d105-1v(S/N 61676-Up) : Fuel System : Water Separator
07***60O-Ring,(For Pc750?800?1800) (A2610)1
60***00Water Separator A.,(See Fig.2415)1
60***10Cover1
See all parts with full part numbers in Heavy Parts AI →
Lubricating Oil System
Komatsu : S6d105-1v(S/N 61676-Up) : Lubricating Oil System : Lubricating Oil Cooler
01***25Bolt,(Without Auto Priming System)5
01***30Bolt,(Cold Terrain Spec.)3
01***35Bolt,(Without Auto Priming System)16
See all parts with full part numbers in Heavy Parts AI →
Komatsu : S6d105-1v(S/N 61676-Up) : Lubricating Oil System : Lubricating Oil Filter And Piping
01***16Bolt,(For Slag Handling)2
01***35Bolt,(Without Auto Priming System)1
01***90Bolt1
See all parts with full part numbers in Heavy Parts AI →
Komatsu : S6d105-1v(S/N 61676-Up) : Lubricating Oil System : Lubricating Oil Pump And Suction Pipe
01***25Bolt,(Without Auto Priming System)3
01***30Bolt,(Cold Terrain Spec.)1
01***45Bolt,(S6d155-4b)1
See all parts with full part numbers in Heavy Parts AI →
Komatsu : S6d105-1v(S/N 61676-Up) : Lubricating Oil System : Turbocharger Lubricating Oil Piping
01***22Bolt,(Cold Terrain Spec.)2
01***35Bolt, Mounting - Flywheel Housing End2
01***25Washer,Spring?(Sandy And Dusty Spec.)2
See all parts with full part numbers in Heavy Parts AI →

S6D105-1V(S/N 61676-UP) serial number reference

The engine serial number plate is located on the left side of the engine block, near the injection pump or on a metal plate affixed to the valve cover area. To read the prefix, identify the alphanumeric model code (e.g., S6D105-1V) stamped on the plate, which indicates the engine family and configuration, followed by the sequential serial number starting from 61676 for this specific range.

PrefixIdentifies
S6D105-1VEngine Model

Frequently asked questions

What engine does the Komatsu S6D105-1V use?

The S6D105-1V is a six-cylinder, turbocharged, direct-injection diesel engine from the Komatsu 6D105 series family. It is mechanically controlled in earlier variants and electronically controlled in later versions, powering machines like the PC200 and PC220 excavators.

What is the operating weight of machines using this engine?

Operating weight varies by configuration and series. Machines powered by the S6D105-1V, such as the PC200 and PC220 excavators, typically range from 19,000 to 25,000 lb (8,600 to 11,300 kg) depending on the boom, stick, and undercarriage setup.

What replaced the Komatsu S6D105-1V?

The S6D105-1V was replaced by the SAA6D107E-1 engine in newer Komatsu excavator generations. The SAA6D107E-1 incorporates advanced emissions technology, including a KDPF and SCR system, to meet Tier 4 Final and Stage V regulations.

What S6D105-1V(S/N 61676-UP) owners discuss

What are the known powertrain and hydraulic behaviors associated with the Komatsu S6D105-1V engine series?
The S6D105-1V is a turbocharged, direct-injection diesel engine delivering approximately 170 horsepower and 550 lb·ft of torque. Community consensus indicates that Komatsu hydraulic systems are generally smooth and fuel-efficient. However, older Dash 6 machines in this engine family are noted for main control valve issues, particularly on PC150 and PC120 models. A critical operational behavior is that hydraulic pump failure often precedes or coincides with engine failure, contributing to lower resale values for this generation of equipment. Operators report that the engine and hydraulics are tightly coupled; if the engine drops RPM heavily under load, the hydraulic system may be placing excessive load on the engine rather than suffering from internal leakage.
What undercarriage and wear patterns are typical for machines powered by this engine series?
Machines equipped with the S6D105-1V series (such as the PC200 and PC220 excavators) exhibit standard heavy-duty undercarriage wear. Common failure points include worn track bushings, bearings, and track pads. Worn bushings lead to increased noise and vibration, while degraded bearings can cause premature track failure. Operators note that track tension must be monitored closely, as repeated loosening is a common issue. The machine is designed to wear out complete systems simultaneously rather than failing gradually in isolated components, meaning undercarriage replacement often coincides with major powertrain or hydraulic overhauls.
What are the specific engine quirks and maintenance requirements for the S6D105-1V series?
The S6D105-1V series (specifically the S6D105-1 variant) utilizes hardened liners, high-alloy piston rings, and a Bosch-style fuel system with injector pressures around 3,200 PSI. This design is considered robust compared to earlier soft-liner or single-head configurations. Maintenance requires strict adherence to Komatsu Genuine Oil specifications, including Komatsu EO diesel engine oil, Komatsu TO powertrain oil, and Komatsu AXO axle oil. The cooling system requires Super-coolant AF-NAC. Operators report that engine performance issues, such as power loss or increased fuel consumption, are often linked to airflow restrictions (clogged charge-air coolers or radiators) or fuel delivery components rather than internal engine wear, provided the engine is kept within operating temperature ranges.
What are the common electrical and sensor issues reported for this engine series?
Komatsu excavators of this generation rely heavily on electronic control systems. Common electrical complaints include intermittent starting, dashboard display failures, and random machine shutdowns. These symptoms are frequently triggered by a single faulty sensor or an unstable power supply. Operators report that multiple fault codes often appear simultaneously due to these electrical instabilities rather than distinct mechanical failures. Grounding issues at the engine and chassis are also cited as a primary cause of erratic sensor behavior and starting difficulties.
What hydraulic behaviors should be monitored when the machine becomes weak when hot?
When hydraulic functions work normally when cold but become weak after the machine reaches operating temperature, the primary suspect is internal leakage that becomes more pronounced as oil viscosity decreases. This pattern points to wear in the hydraulic pump, main control valve, travel motors, or swing motors. Operators are advised to measure system performance both cold and hot to confirm this diagnosis. It is critical not to replace the hydraulic pump immediately based solely on temperature behavior; pressure and flow testing is required to distinguish between pump wear and main control valve leakage.
What should be checked when buying a used machine with the S6D105-1V engine (S/N 61676-UP)?
When inspecting a used machine with this engine serial range, verify the exact engine model against the equipment guide, as the S6D105-1V (S/N 61676-UP) may be associated with specific grader or excavator models like the PW400MH-6 or GD300-A. Check for signs of the 'Dash 6' era valve problems if the machine is an older PC150 or PC120. Inspect the cooling package (radiator, hydraulic oil cooler, charge-air cooler) for packed debris, as overheating is a common failure mode. Verify the condition of the undercarriage, as track tension and component wear are critical. Finally, test all hydraulic functions both cold and hot to identify viscosity-related leakage, and check for electrical grounding issues that cause intermittent starting or dashboard faults.
What is the safety-critical fix for engine overheating during heavy excavation?
If the engine overheats during heavy work, stop the machine immediately to prevent catastrophic damage. Inspect the cooling package for debris packed between the radiator, hydraulic oil cooler, and charge-air cooler. Check the coolant level when the engine is cold and verify fan operation. If the system becomes highly pressurized or expels coolant shortly after a cold start, deeper engine diagnosis is required. Have your dealer verify the cooling system integrity and thermostat operation to ensure safe operating temperatures.

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

Need a specific S6D105-1V(S/N 61676-UP) part?

Search live OEM part data, check fitment, and cross-reference alternatives with Heavy Parts AI.