Komatsuengine(no series)

Komatsu 6D105-1BB(S/N 62390-UP)

Maintenance schedule, common problems & OEM parts breakdown

The 6D105-1BB is a specific factory build within Komatsu's 6D105-1 family of mechanical, jerk-pump-injected industrial diesel engines: an inline 6-cylinder unit with a 105 mm x 125 mm (4.13 in x 4.92 in) bore and stroke, roughly 6.49 liter displacement, direct injection, and no engine control module. It belongs to the Dash-1 generation of Komatsu's mechanical-engine era, and the S/N 62390-UP block is factory-documented against the WA200-1 wheel loader, a mid-size wheel loader in roughly the 9.5 to 9.7 tonne operating-weight class. Komatsu offered the 6D105-1 architecture across several parallel build codes (1F, 1L, 1M-A, 1M-AM, 1M-F, and 1M-P among them), each tied to its own serial range and host application, with the 1BB code representing the configuration and accessory rating built for this particular chassis and duty cycle.

Across the 6D105-1 lineup the core architecture stayed constant while accessory drives, injection calibration, and turbocharging carried the differences between build codes, and later Komatsu dash generations moved this same bore family toward turbocharged and eventually electronically governed variants. No factory record ties a direct one-model successor to this exact suffix and serial block, so continuity today runs through parts and rebuild support rather than a documented replacement engine. That is also where its market value sits: a simple, ECM-free mechanical diesel with well-understood wear points, injector seepage, cooling-system seal wear, and liner-driven oil consumption, is comparatively cheap to diagnose and rebuild in the field, which keeps 6D105-1BB units and cores in active demand among rebuilders and independent shops long after the host machine itself left production.

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 6D105-1BB(S/N 62390-UP) specifications

Engine

Engine modelKomatsu 6D105-1 series, production build 6D105-1BB (applies from engine serial no. 62390 and up)
ConfigurationInline 6-cylinder, water-cooled diesel, direct injection
Displacement6.49 L (6,494 cc)
Bore x stroke105 mm x 125 mm
AspirationNaturally aspirated per the 6D105-1 base-series shop manual; not documented specifically for the 1BB production build — verify aspiration and turbo fitment against the host machine's own engine tag before ordering parts
Gross/net powerNot published for this specific serial-range build. Across 6D105-1-series installations in period Komatsu machines, rated flywheel output runs roughly 70-82 kW (95-110 PS/hp) depending on host machine and governed speed — varies by configuration/series
Emissions tierNone — mechanical, pre-emissions-regulation diesel (no ECM, no aftertreatment)

Weights

Operating/shipping weightNot documented for the bare engine. As factory-fitted to its documented host, a wheel loader, the machine sits in roughly the 9.5 to 9.7 tonne operating-weight class, varying by bucket, counterweight, and configuration
Ground pressureNot applicable — no ground-engaging chassis is defined for this engine record

Dimensions

Transport length/width/heightNot documented for this bare-engine serial-range build
Wheelbase / track gaugeNot applicable — no chassis is defined for this engine record
Ground clearanceNot documented

Performance

Travel speedNot applicable — this record is a bare engine build/serial break, not a complete machine, so no travel-speed or drivetrain performance figures apply
Class performance (lift/dig/dump/drawbar)Not applicable for a bare engine assembly
GradeabilityNot published

Service capacities (summary)

Engine oil capacityAbout 24 L total pan capacity, about 23 L on a filter-change refill (6.3 US gal / 6.1 US gal), per the 6D105-1 series shop manual
Cooling system capacityNot fixed for the bare engine — family shop data shows a wide 21 to 44 L (5.5 to 11.6 US gal) range depending on the host machine's radiator package; confirm against the host machine's own operation manual
Fuel tank capacityNot applicable to a bare engine record — fuel tank sizing is set by the host machine, which is not confirmed for this exact serial range
Hydraulic system capacityNot applicable — this is an engine, not a complete hydraulic machine

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

6D105-1BB(S/N 62390-UP) fluids & capacities

SystemCapacityRecommended fluid
Engine crankcase (with oil filter)About 24 L total pan capacity, about 23 L on a filter-change refill (6.3 US gal / 6.1 US gal)Komatsu Genuine diesel engine oil (EO series). Same-family shop data calls for SAE 30 in normal ambient conditions and SAE 10W below 0°C (32°F) on this engine generation; current-issue Komatsu Genuine EO10W-30 covers roughly -30°C to 30°C and EO15W-40 suits warmer ranges. Use an oil meeting at minimum API CD/CE-class diesel engine oil performance.
Cooling system (radiator + block)Not fixed for the bare engine — shop data for this 6D105-1 engine family shows a wide 21 to 44 L (5.5 to 11.6 US gal) range depending on the radiator/cooling package of the machine it is installed in; confirm against the actual host machine's OMMKomatsu Genuine Super Coolant (AF-NAC), an ethylene-glycol, phosphate/OAT-type, factory pre-mixed (50/50) antifreeze-corrosion inhibitor coolant. Do not mix with silicate-type coolants. Change interval per Komatsu genuine coolant is 2 years or 4,000 service hours, whichever comes first.
Fuel systemFuel tank capacity is set by the host machine and is not published for the bare 6D105-1BB engineDiesel fuel to ASTM D975 No. 2-D for normal service; switch to No. 1-D (winter/cold grade) below 0°C (32°F) for reliable cold starting, per the shared 6D105-1 engine family fuel spec.
Grease pointsPer fitting, no reservoir volume specifiedKomatsu Genuine multipurpose lithium-base grease (G2-LI), NLGI No. 2 for normal ambient temperatures; switch to a softer NLGI No. 0/1 grade in sustained sub-freezing conditions.

Capacities are refill values from factory literature — always fill to the dipstick/sight gauge, not the number.

Komatsu 6D105-1BB(S/N 62390-UP) maintenance schedule

Service intervalTasks
Every 50 h
  • Check engine oil level before starting and top up to the full mark (daily).
  • Drain water and sediment from the fuel pre-filter/water separator (daily).
  • Check coolant level in the radiator and sub-tank and inspect hose fittings for leaks (daily).
  • Listen for abnormal engine noise and check exhaust smoke color at startup (daily).
  • Check the air-cleaner restriction indicator and service the element if it trips (weekly).
  • Check fan and alternator belt tension and inspect belts for cracking (weekly).
Every 250 h
  • Change engine oil and replace the oil filter.
  • Replace the fuel filter cartridge and bleed the fuel system.
  • Check battery electrolyte level and clean terminal connections.
  • Inspect and adjust drive-belt tension for the water pump and alternator.
  • Clean the crankcase breather.
Every 500 h
  • Drain and clean the fuel tank of accumulated water and sediment.
  • Inspect the exhaust manifold and its mounting hardware for leaks and loose fasteners.
  • Test coolant condition and corrosion-inhibitor concentration.
  • Check engine mounting bolts and rubber isolators for wear or looseness.
  • Inspect starter and charging-circuit wiring for corrosion or loose connections.
Every 1,000 h
  • Check and adjust intake and exhaust valve clearances to factory spec.
  • Test fuel injection nozzles, reset opening pressure, and recondition any unit seeping at idle.
  • Check fuel injection pump timing against factory spec.
  • Replace coolant and inspect the water pump for shaft play or seal seepage.
  • Check cylinder compression or blow-by if oil consumption is trending upward.
Every 2,000 h
  • Overhaul the fuel injection pump and recalibrate it on a test bench.
  • Replace the water pump if seal weeping was noted at prior inspections.
  • Inspect the vibration damper for cracking or fluid loss.
  • Check main and connecting-rod bearing clearances if oil pressure has been trending down.
  • Flush and refill the complete cooling system.
Every 4,000 h
  • Remove and measure cylinder liners, pistons, and rings against factory wear limits.
  • Recondition the cylinder head, including valves, seats, and guides.
  • Inspect crankshaft journals and replace main and rod bearings as a set.
  • Rebuild or exchange the fuel injection pump internals.
  • Replace the water pump and thermostat together as part of the overhaul.

Servicing the 6D105-1BB(S/N 62390-UP) beyond the schedule

Predictive Maintenance & Fluid Analysis

Because the 6D105-1BB carries no ECM, condition monitoring depends on manual sampling rather than fault codes. Pull an oil sample at each interval and watch for rising iron and chrome content, the early flag for the cylinder-liner wear this family is known for. Track fuel filter and injector seepage visually, since nozzle drip is the most common fuel-system failure mode. Test coolant concentration and inhibitor level rather than relying on visual clarity, particularly given the wide range of radiator packages fitted to its host.

Corrective & Common Repairs

Most corrective work on this engine centers on the fuel and cooling systems. Injector nozzles that seep at idle should be pulled, tested, and reseated rather than left to wash down cylinder walls. Water pump seal weeping and head gasket seepage are common cooling-system repairs at higher hours. Because injection timing and governor linkage are set mechanically, drivability complaints are traced with a timing light and linkage gauge, not a scan tool.

Overhaul & Rebuild Points

A full overhaul on the 6D105-1BB centers on the fuel-injection pump and the cylinder pack. Liner wear tracks directly to the oil-consumption complaints reported on this family, so bore and liner measurement is the first overhaul check, followed by ring and bearing clearances. The mechanical injection pump needs bench calibration and nozzle opening-pressure resets rather than software reflash. Valve seats and guides are reconditioned on the same schedule, since there is no electronic idle or fuel trim to mask a worn seat.

Seasonal & Environment Servicing

Cold starts on this mechanical engine rely on correct-viscosity oil, a sound battery, and a block heater or starting aid rather than any ECM-managed glow strategy, so pre-winter service should confirm all three. In hot or dusty operating environments, shorten the air-cleaner and fuel-filter service interval, since the jerk-pump fuel system is unforgiving of contamination reaching the plungers. Because coolant capacity depends on the host radiator package, always verify fill volume before topping up rather than assuming a family-wide figure.

6D105-1BB(S/N 62390-UP) common service parts

Part numberPart
07281-00197Clamp,(With Pre-Fuel Filter)Check fitment →
600-311-9100Fuel Filter Ass'YCheck fitment →
600-311-8221Cartridge,Engine Fuel FilterCheck fitment →
6136-71-6120Cartridge,Engine Fuel FilterCheck fitment →
6136-72-6100Fuel Filter Ass'YCheck fitment →

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

6D105-1BB(S/N 62390-UP) attachments & work tools

Host machine

6D105-1BB (S/N 62390-UP) is the factory-fit power unit for the Komatsu WA200-1 wheel loader production block beginning at this chassis serial. It is not documented as a standalone genset or industrial power-unit application for this serial range.

Bucket - general purpose

Standard work tool for this loader class is a general-purpose earthmoving bucket, around 1.7 m3 struck capacity, sized to the host loader's roughly 9.5-9.7 t operating weight. Bolt-on replaceable cutting edge is standard; bucket teeth are an added option, not standard fit.

Pallet forks

Fork/carriage attachments were offered for this loader size class for yard and material-handling duty, mounted on the same boom linkage as the bucket. Rated lift capacity follows the loader's static tipping load rating rather than a bucket-specific figure.

Work-tool mounting / coupler

This production block uses a direct pin-mounted bucket/fork linkage rather than a hydraulic quick-coupler tool carrier; swapping tools means pulling the linkage pins. Komatsu's later hydraulic quick-coupler tool-carrier arrangement for this loader class belongs to newer WA200 generations, not this serial range - verify tool-carrier fitment with your dealer before assuming compatibility.

Loader hydraulic implement pump

The engine drives the loader's boom-lift and bucket-tilt hydraulic pump directly off the flywheel/gear train. This engine-driven pump is the closest equivalent to a PTO on this engine, and it is dedicated to the machine's own work-equipment circuit rather than an auxiliary drive for separate implements.

Cooling package

Radiator and engine-driven cooling fan are packaged for a front-engine wheel-loader installation (fan draws air through the radiator ahead of the engine). Other host applications sharing the base 6D105 engine family use different fan shrouding and radiator arrangements, so cooling hardware is not interchangeable across hosts.

Charging / alternator

Engine carries a vehicle-duty alternator sized for the loader's lighting, instrumentation, and starting circuit. No dedicated generator-end or genset pairing is documented for this serial range.

Transmission pairing

Engine is matched to a torque-converter powershift transmission and loader-type axles typical of the WA200-1 class. This is a factory driveline configuration, not a bolt-on work tool, and is noted here as a factory arrangement rather than an attachment.

All 6D105-1BB(S/N 62390-UP) assemblies by section

Every catalogued assembly group for the Komatsu 6D105-1BB(S/N 62390-UP). Open an assembly to preview the parts inside — full OEM part numbers are available in Heavy Parts AI.

Cooling System
Komatsu : 6d105-1bb(S/N 62390-Up) : Cooling System : Corrosion Resistor And Piping
01***25Bolt,(Sandy? Dusty Terrain Spec.)4
01***29Washer,Spring (Cold Weather Spec.)4
01***30Washer, Spring (Supplied W/Spider Assembly), Washer-Spring4
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Cooling System : Water Pump And Cooling Fan
01***16Bolt,(For Slag Handling)2
01***30Bolt,(Cold Terrain Spec.)3
01***55Bolt,(For Suction? Reversible Fan)2
See all parts with full part numbers in Heavy Parts AI →
Cylinder Block
Komatsu : 6d105-1bb(S/N 62390-Up) : Cylinder Block : Camshaft And Tappet
01***25Bolt,(Without Auto Priming System)2
01***25Washer,Spring?(Sandy And Dusty Spec.)2
01***16Washer,(For 35a Alternator)2
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Cylinder Block : Crankshaft
01***25Bolt - Rear Guard Mounting6
01***45Bolt,Nylock1
01***36Washer,Radio Controlled Slag Handling6
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Cylinder Block : Crankshaft (With Air Conditioner)
01***70Bolt, Heater Hose Clip6
01***45Bolt1
01***36Washer,Radio Controlled Slag Handling6
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Cylinder Block : Cylinder Block (With Turbocharger)(#86387-)
01***30Bolt,(For France Noise Suppression)3
01***45Bolt,(For Suction? Reversible Fan)1
01***20Bolt,(Used When Towing Winch)1
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Cylinder Block : Cylinder Block(#86387-)
01***30Bolt,(For France Noise Suppression)4
01***20Bolt,(Used When Towing Winch)1
01***30Washer,Spring(Sandy?Dusty Terrain S.)4
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Cylinder Block : Flywheel And Flywheel Housing (Key Stop Type)(#86387-)
01***35Bolt - Torque Converter Totransmission Mounting2
01***40Bolt,(Dust And Dirt Protection)9
01***45Bolt,(Cold Terrain Spec.)2
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Cylinder Block : Flywheel And Flywheel Housing (Pedal Stop Type)(#86387-)
01***35Bolt - Torque Converter Totransmission Mounting2
01***40Bolt,(Dust And Dirt Protection)9
01***45Bolt,(Cold Terrain Spec.)2
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-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)10
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Cylinder Block : Oil Pan
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 : 6d105-1bb(S/N 62390-Up) : Cylinder Block : Oil Pan (With Oil Level Sensor)
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 : 6d105-1bb(S/N 62390-Up) : Cylinder Block : Oil Pan (Without Oil Level Sensor)(#86387-)
01***22Bolt,(Cold Terrain Spec.)29
01***30Bolt,(Cold Terrain Spec.)1
01***25Bolt,(Sandy? Dusty Terrain Spec.)8
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Cylinder Block : Piston And Connecting Rod
04***18Ring, Retaining2
61***30Piston Ring Ass'Y6
61***10Pin,Piston1
See all parts with full part numbers in Heavy Parts AI →
Cylinder Head
Komatsu : 6d105-1bb(S/N 62390-Up) : Cylinder Head : Air Cleaner And Mounting (Tunnel Spec.)(#86387-)
01***25Bolt,(Sandy? Dusty Terrain Spec.)4
01***25Bolt (M10x1.50x25)2
01***45Screw1
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Cylinder Head : Air Cleaner And Mounting (With Turbocharger)(#86387-)
01***25Bolt,(Sandy? Dusty Terrain Spec.)2
01***25Bolt (M10x1.50x25)2
01***08Nut,R.H. Thread6
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Cylinder Head : Air Cleaner And Mounting(#86387-)
01***25Bolt,(Sandy? Dusty Terrain Spec.)4
01***25Bolt (M10x1.50x25)2
01***45Screw1
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Cylinder Head : Air Intake Manifold And Connection (With Turbocharger)
01***20Bolt2
01***50Bolt,(For Trimming Dozer)2
01***65Bolt,(For Alternator Bracket Mount)5
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Cylinder Head : Air Intake Manifold And Connection(#78380-)
01***20Bolt2
01***50Bolt,(For Trimming Dozer)2
01***65Bolt,(For Alternator Bracket Mount)5
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Cylinder Head : Cylinder Head (With Turbocharger)
01***30Bolt,(For France Noise Suppression)2
01***30Washer,Spring(Sandy?Dusty Terrain S.)2
01***16Washer,(With Shoe Slip Control)2
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Cylinder Head : Cylinder Head Cover(#79183-)
07***23Clamp - Hose1
07***00Clip1
07***30Clip1
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Cylinder Head : Cylinder Head(#86387-)
01***30Bolt,(For France Noise Suppression)2
01***30Washer,Spring(Sandy?Dusty Terrain S.)2
01***16Washer,(With Shoe Slip Control)2
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Cylinder Head : Exhaust Manifold And Mounting
01***60Bolt (M10-1.50x60)1
01***00Bolt (M10-1.50x100)11
61***60Spacer1
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Cylinder Head : Exhaust Manifold And Turbocharger (With Turbocharger)
01***60Bolt (M10-1.50x60)1
01***00Bolt (M10-1.50x100)11
01***32Washer,(With Auto Emergency Steering)1
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Cylinder Head : Muffler And Mounting
01***20Bolt,(Large Capacity Type) (Std)2
01***25Bolt,(Sandy? Dusty Terrain Spec.)4
01***11Nut (M14-1.50 Thd), Nut; Was 01582-014112
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Cylinder Head : Muffler And Mounting (With Turbocharger)
01***40Bolt,(Dust And Dirt Protection)4
01***45Bolt,(For Suction? Reversible Fan)4
01***95Bolt,(For Reversible Fan)2
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Cylinder Head : Muffler And Mounting(#75963-)
01***20Bolt,(Large Capacity Type) (Std)2
01***25Bolt,(Sandy? Dusty Terrain Spec.)4
01***16Bolt4
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Cylinder Head : Muffler And Mounting(#86387-)
01***20Bolt,(Large Capacity Type) (Std)2
01***25Bolt,(Sandy? Dusty Terrain Spec.)4
01***16Bolt4
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-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 : 6d105-1bb(S/N 62390-Up) : Cylinder Head : Turbocharger
61***00Turbocharger Ass'Y1
GA***00Clamp3
GA***01Bolt6
See all parts with full part numbers in Heavy Parts AI →
Electrical System
Komatsu : 6d105-1bb(S/N 62390-Up) : Electrical System : Alternator (25a) (With Non Hardening Pulley)
60***20Alternator A. (25a),(With Non Hardening Pulley)1
KD***57Bearing,Ball? Front1
KD***80Collar1
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Electrical System : Alternator (35a) (Drip-Proof Type) (With Non Hardening Pulley)
60***60Alternator A. (35a),(With Non Hardening Pulley)1
KD***31Bushing,Insulator2
KD***57Bearing,Ball? Front1
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Electrical System : Alternator (35a) (With Hardening Pulley)
60***20Alternator A. (35a),(With Hardening Pulley)1
KD***57Bearing,Ball? Front1
KD***80Collar1
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Electrical System : Alternator (35a) (With Non Hardening Pulley)(#70635-)
60***80Alternator A. (35a),(With Non Hardening Pulley)1
KD***57Bearing,Ball? Front1
KD***80Collar1
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Electrical System : Alternator (50a) (With Hardening Pulley)
60***90Alternator A. (50a),(With Hardening Pulley)1
SD***X0Washer1
SD***X0Fan1
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Electrical System : Alternator (50a) (With Non Hardening Pulley)(#62390-70634)
60***40Alternator A. (50a),(With Non Hardening Pulley)1
SD***X0Coil Assembly1
SD***X0Washer1
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Electrical System : Alternator (50a) (With Non Hardening Pulley)(#86387-)
60***90Alternator A. (50a),(With Non Hardening Pulley)1
SD***X0Washer1
SD***X0Fan1
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Electrical System : Alternator (75a) (With Non Hardening Pulley)(#70635-)
60***40Alternator A. (75a),(With Non Hardening Pulley)1
SD***X0Coil Assembly1
SD***X0Bracket, Rear1
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Electrical System : Alternator And Mounting (25a) (Alternator With Non Hardening Pu- Lley) (Bracket Less Type)(#93942-)
01***45Bolt,(For Suction? Reversible Fan)1
01***35Bolt,(Cold Weather Spec.)1
01***10Nut,(Dust?Drip Proof? Trimming S.)1
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Electrical System : Alternator And Mounting (25a) (Alternator With Non Hardening Pu- Lley) (Bracket Mounting Type)(#62390-93941)
01***65Bolt,(For Alternator Bracket Mount)2
01***25Bolt,(Sandy? Dusty Terrain Spec.)1
01***70Bolt,(With Wear Guard)1
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Electrical System : Alternator And Mounting (35a) (Bracket Less Type)(#93942-)
01***45Bolt,(For Suction? Reversible Fan)1
01***35Bolt,(Cold Weather Spec.)1
01***10Nut,(Dust?Drip Proof? Trimming S.)1
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Electrical System : Alternator And Mounting (35a) (With Non Hardening Pulley) (Drip- Proof Type) (Bracket Mounting Type)
01***65Bolt,(For Alternator Bracket Mount)2
01***25Bolt,(Sandy? Dusty Terrain Spec.)1
01***70Bolt,(With Wear Guard)1
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Electrical System : Alternator And Mounting (50a) (Bracket Mounting Type)(#86387-)
01***65Bolt,(For Alternator Bracket Mount)2
01***40Bolt,(Dust And Dirt Protection)1
01***70Bolt,(With Wear Guard)1
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Electrical System : Alternator And Mounting (50a? 35a) (Alternator With Non Hardenongpulley)(#62390-93941)
01***65Bolt,(For Alternator Bracket Mount)2
01***25Bolt,(Sandy? Dusty Terrain Spec.)1
01***70Bolt,(With Wear Guard)1
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Electrical System : Alternator And Mounting (75a) (With Non Hardening Pulley) (Bracket Mounting Type)(#70635-)
01***65Bolt,(For Alternator Bracket Mount)2
01***25Bolt,(Sandy? Dusty Terrain Spec.)1
01***70Bolt,(With Wear Guard)1
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Electrical System : Heater Switch And Heater Signal(#75963-)
60***71Signal,Signal1
(6***0)Switch,Heater (See Fig.0131 Or 0131a)1
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Electrical System : Starting Motor (5.5kw)
60***90Starting 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 : 6d105-1bb(S/N 62390-Up) : Electrical System : Starting Motor (7.5kw)(#62390-80844)
60***50Starting Motor Ass'Y,(7.5kw) (S6d105-1x)1
KD***20Magnetic Switch Assembly1
KD***40Spring,Spring4
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Electrical System : Starting Motor (7.5kw)(#75963-)
60***20Starting Motor A.,(7.5kw)1
KD***30Washer Ass'Y,(Not Shown)1
KD***60Terminal Ass'Y1
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Electrical System : Starting Motor (7.5kw)(#80845-)
60***50Starting Motor Ass'Y,(7.5kw)1
KD***60Shift Lever Assembly1
KD***40Spring,Spring4
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Electrical System : Starting Motor And Mounting (5.5kw? 7.5kw)
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 →
Komatsu : 6d105-1bb(S/N 62390-Up) : Electrical System : Starting Motor And Mounting (7.5kw)(#75963-)
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 : 6d105-1bb(S/N 62390-Up) : Engine Kit : Gasket Kit (With Turbocharger)(#86387-)
07***18O-Ring,(See Fig.1601-29?1602-17)1
07***70O-Ring,(For Intake Air Cover)1
07***00O-Ring,(F4350-65a1 -5 )1
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Engine Kit : Gasket Kit(#86387-)
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 : 6d105-1bb(S/N 62390-Up) : Fuel System : Additional Fuel Filter
07***12Gasket,Mechanical Pump Piping2
60***00Fuel Filter Ass'Y1
60***20Cartridge,Pref1
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Fuel System : Fuel Filter And Piping
01***30Bolt,(For France Noise Suppression)4
01***30Washer,Spring(Sandy?Dusty Terrain S.)4
01***16Washer,(With Shoe Slip Control)2
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Fuel System : Fuel Injection Pump (Coupling)
61***51Injection Pump Ass'Y1
61***52Injection Pump Ass'Y1
DK***00Bolt1
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Fuel System : Fuel Injection Pump (Coupling) (With Turbocharger)
Komatsu : 6d105-1bb(S/N 62390-Up) : Fuel System : Fuel Injection Pump (Coupling)(#86387-)
DK***00Bolt1
DK***00Washer,Lock2
DK***00Coupling,Cross1
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Fuel System : Fuel Injection Pump (Feed Pump)
61***51Injection Pump Ass'Y1
61***52Injection Pump Ass'Y1
DK***20Bolt, Joint1
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Fuel System : Fuel Injection Pump (Feed Pump) (With Turbocharger)
DK***20Bolt, Joint1
DK***20Pump,Priming1
DK***20Housing1
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Fuel System : Fuel Injection Pump (Feed Pump) (With Turbocharger)(#86387-)
DK***20Bolt, Joint1
DK***20Pump,Priming1
DK***20Housing1
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Fuel System : Fuel Injection Pump (Governor) (1/2) (With Turbocharger)
DK***00Adapter1
DK***80Nut1
DK***00Nut,Lock1
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Fuel System : Fuel Injection Pump (Governor) (1/2) (With Turbocharger)(#86387-)
DK***00Adapter1
DK***80Nut1
DK***00Nut,Lock1
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Fuel System : Fuel Injection Pump (Governor) (2/2) (With Turbocharger)
DK***40Gasket,Air Compressor2
DK***00Nut,Cap1
DK***00Bushing1
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Fuel System : Fuel Injection Pump (Governor) (2/2) (With Turbocharger)(#86387-)
DK***40Gasket,Air Compressor2
DK***00Nut,Cap1
DK***00Spring1
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Fuel System : Fuel Injection Pump (Governor) (2/2)(#75883-)
61***52Injection Pump Ass'Y1
DK***40Gasket,Air Compressor2
DK***00Nut,Cap1
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Fuel System : Fuel Injection Pump (Pump)
61***50Injection Pump Ass'Y1
61***51Injection Pump Ass'Y1
61***52Injection Pump Ass'Y1
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Fuel System : Fuel Injection Pump (Pump) (With Turbocharger)
61***70Injection Pump Ass'Y1
DK***10Washer,Spring1
DK***20Housing1
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Fuel System : Fuel Injection Pump (Pump) (With Turbocharger)(#86387-)
61***80Injection Pump Ass'Y1
DK***10Washer,Spring1
DK***20Housing1
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Fuel System : Fuel Injection Pump And Piping (With Turbocharger)(#86387-)
Komatsu : 6d105-1bb(S/N 62390-Up) : Fuel System : Fuel Injection Pump And Piping(#86387-)
01***70Bolt4
01***20Bolt,(Large Capacity Type) (Std)1
01***25Bolt,(Sandy? Dusty Terrain Spec.)1
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Fuel System : Fuel Nozzle And Spill Pipe
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 : 6d105-1bb(S/N 62390-Up) : Fuel System : Solenoid And Mounting(#75883-)
01***20Bolt4
01***50Bolt - Torque Converter Totransmission Mounting2
01***03Nut? L.H. Thread,L.H. Thread1
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Fuel System : Water Separator
07***60O-Ring,(For Pc750?800?1800) (A2610)1
60***00Water Separator A.,(4d105-5h? 4d105-5t)1
60***60Plug,Drain (4d105-5h? 4d105-5t)1
See all parts with full part numbers in Heavy Parts AI →
Lubricating Oil System
Komatsu : 6d105-1bb(S/N 62390-Up) : Lubricating Oil System : Lubricating Oil Cooler
01***25Bolt,(Without Auto Priming System)7
01***30Bolt,(Cold Terrain Spec.)3
01***35Bolt,(Without Auto Priming System)12
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Lubricating Oil System : Lubricating Oil Cooler(#75963-)
01***25Bolt,(Without Auto Priming System)7
01***30Bolt,(Cold Terrain Spec.)3
01***35Bolt,(Without Auto Priming System)12
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Lubricating Oil System : Lubricating Oil Filter And Mounting (With Turbocharger)
01***65Bolt,(For Alternator Bracket Mount)1
01***25Bolt,(Sandy? Dusty Terrain Spec.)3
01***35Bolt, Mounting - Flywheel Housing End1
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-Up) : Lubricating Oil System : Lubricating Oil Filter And Mounting (With Turbocharger)(#86387-)
01***65Bolt,(For Alternator Bracket Mount)1
01***16Bolt,(Sandy And Dusty Spec.)2
01***25Bolt,(Sandy? Dusty Terrain Spec.)3
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-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 : 6d105-1bb(S/N 62390-Up) : Lubricating Oil System : Lubricating Oil Filter Piping (With Turbocharger)
01***16Bolt,(For Slag Handling)2
01***95Bolt1
01***55Bolt,(For Suction? Reversible Fan)3
See all parts with full part numbers in Heavy Parts AI →
Komatsu : 6d105-1bb(S/N 62390-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 : 6d105-1bb(S/N 62390-Up) : Lubricating Oil System : Turbocharger Lubricating Oil Piping (With Turbocharger)
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 →

6D105-1BB(S/N 62390-UP) serial number reference

The engine data plate is riveted to the rocker (cylinder head) cover or to the left side of the cylinder block near the fuel injection pump, stamped with the full model code (6D105-1BB) and the engine serial number; the wheel loader's own machine PIN plate sits on the frame near the articulation joint or inside the cab on the right console post. Read the engine suffix letters after the dash (here "1BB") together with the serial run (62390-UP) as one unit - swapping either half of that code onto a different loader or generation will pull the wrong parts and torque data.

PrefixIdentifies
WA200-1Wheel loader host, chassis S/N 10001-UP

Frequently asked questions

What engine is the 6D105-1BB (S/N 62390-UP)?

It is a Komatsu inline 6-cylinder diesel engine: 105 mm x 125 mm (4.13 in x 4.92 in) bore and stroke, roughly 6.49 liter displacement, mechanical jerk-pump direct injection, and no electronic control module. Engine oil capacity runs about 24 liters (6.3 US gal) total, with coolant capacity depending on the radiator package fitted by the host machine.

What is the operating weight of the 6D105-1BB machine?

The 6D105-1BB is the engine itself, so it has no published operating weight of its own. As factory-fitted to its documented host, a mid-size wheel loader, the machine sits in roughly the 9.5 to 9.7 tonne operating-weight class, with exact figures varying by bucket, counterweight, and other configuration choices on the host chassis.

What replaced the 6D105-1BB (S/N 62390-UP)?

No factory record documents a direct one-to-one successor tied to this specific suffix and serial block. The broader 6D105 architecture carried forward into later Komatsu dash generations with turbocharged and eventually electronically governed variants, but for this exact build the practical path today is parts and rebuild support rather than a drop-in factory replacement.

What 6D105-1BB(S/N 62390-UP) owners discuss

What do owners say about starting this engine in cold weather?
As a naturally aspirated, mechanical-injection block, it needs a full glow-plug preheat cycle before cranking in cold conditions, and operators are warned that starting fluid and working glow plugs don't mix well together. A weak or partially failed glow plug element is the most commonly reported cause of a hard cold start on this engine family. If cold starting doesn't improve after fresh glow plugs, have a qualified dealer check the starting circuit and injection pump timing.
What's the most commonly reported fuel-system wear point on this engine family?
Fuel nozzles seeping fuel or oil out around the injection tube where they seat in the cylinder head is a recurring complaint as these engines age, usually traced to a worn sealing washer under the nozzle rather than the injector body itself. The old washer often stays stuck in the injector bore during removal and has to be picked out before a new nozzle will seat and seal correctly. Because this is a sealed high-pressure fuel joint, have a qualified dealer verify injector seating and torque after any nozzle service.
Any recurring cooling-system complaints on this engine?
Head gaskets and water pumps are the components most frequently replaced on these mechanical-injection sixes as hours accumulate, and once one starts weeping coolant or oil it's treated as routine end-of-life wear rather than a defect. Persistent overheating after a coolant top-off is more often traced to the water pump or a marginal head gasket than to the radiator itself. Any coolant-leak repair should be pressure-tested and verified by a qualified dealer before returning the engine to service.
Is rising oil consumption or smoke normal on a high-hour unit?
Gradually increasing oil consumption at higher hours is generally read as normal cylinder liner and ring wear on this engine, used as a rebuild-timing indicator rather than a sign of sudden failure. Sudden heavy blue or black smoke is treated differently and points to something acute, such as a failing injector or a ring/liner problem accelerating quickly. A compression or blow-by check from a qualified dealer is the standard way to tell gradual wear apart from an active fault.
Does this engine have onboard diagnostics or fault codes like later Komatsu engines?
No. This is a pre-electronic, mechanical-injection-era block with no ECM, so there is no fault-code monitor the way later electronically governed Komatsu engines have. Troubleshooting relies on mechanical symptoms instead — smoke color, fuel delivery pressure at the pump, compression, and coolant condition. Electrical complaints on this generation are almost always limited to the starter motor, alternator, and glow-plug relay wiring rather than sensor or module faults.
What's the engine's general reputation among owners who ran it in its factory-fitted wheel loader?
Owners of Komatsu wheel loaders from this size class and era generally describe the mechanical drivetrain as reliable and low-drama when fuel and cooling maintenance is kept current, with complaints centered on age-related wear parts (injectors, water pump, seals) rather than any design flaw. That matches how the bare 6D105-1 block is regarded on its own: simple and durable, but it rewards routine upkeep. Historical parts-book cross-reference points to a WA200-1-class chassis for this engine, so for any chassis-specific symptom, have a qualified dealer confirm the exact host machine and serial range first.
What should I check before buying a used or reman 6D105-1BB core?
Confirm the block's stamped serial number actually falls in the 62390-and-up range, since the 6D105-1 family was sold under several sub-suffixes with differing internal specs and cores get mixed up. Ask for a compression or leak-down test result and inspect around the head gasket area for oil-in-coolant or coolant-in-oil contamination before paying for a unit sold as tested. Check the injector nozzle seats for seepage staining, and confirm the crank turns freely by hand or that a recent test-run/dyno record exists, to rule out a seized cylinder. Because a mismatched or misrepresented core leads to costly rework, have a qualified dealer or engine shop verify serial range, compression, and fitment before final purchase.

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

Need a specific 6D105-1BB(S/N 62390-UP) part?

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