Komatsuengine(no series)

Komatsu S6D155-4J(S/N 22144-UP)

Maintenance schedule, common problems & OEM parts breakdown

The Komatsu S6D155-4J engine (S/N 22144-UP) is a turbocharged, six-cylinder diesel powerplant designed for heavy-duty construction applications. It primarily powers the D155A and D155W crawler dozer series, which are large earthmoving machines with operating weights ranging from approximately 59,350 lbs (26,943 kg) to 87,083 lbs (39,474 kg) depending on configuration. Production for this engine series spans the late 1980s through the mid-1990s. It succeeded earlier 155-series designs and was eventually replaced by the S6D170E-2A and S6D170-1L engines in subsequent dozer generations. Configurations included standard and high-altitude variants, with gross power outputs reaching 320 hp (239 kW).

Across its production life, the S6D155-4J evolved through Build 14A revisions, incorporating updates to fuel injection and emissions compliance to meet evolving Tier 4 and Stage III standards. The machine remains significant in the used and parts market due to its robust cast-iron block and widespread use in heavy grading and mining. Its longevity has created a strong aftermarket for overhaul kits, cylinder liners, and undercarriage components. The S6D155-4J is often sought for remanufacturing projects because its modular design allows for cost-effective in-frame and out-of-frame rebuilds, keeping older D155 series dozers operational longer than many competitors.

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 S6D155-4J(S/N 22144-UP) specifications

Engine

ModelS6D155-4J
Series155-4 Series
Gross Power320 hp (239 kW)
Net Power210-240 hp (156-178 kW) @ 1850 rpm
Displacement12.840 L (783.6 cu in)
Cylinders6
ArrangementIn-line, turbocharged
Bore155.0 mm (6.10 in)
Stroke170.0 mm (6.69 in)
Emissions TierTier 4 Final / EU Stage V

Weights

Operating Weight59,350 lb (26,920 kg)
Engine Weightapprox. 2,050 kg (4,520 lb)

Dimensions

Engine Lengthapprox. 1,456 mm (57.3 in)
Engine Widthapprox. 1,125 mm (44.3 in)
Engine Heightapprox. 1,910 mm (75.2 in)
Transport Length13.6 ft in (4.14 m)
Transport Width62.6 in (1.59 m)
Ground Clearance13.7 yd3 (Note: Source lists '13.7yd3' in dimension sequence; likely refers to bucket capacity or is a data error for clearance. Omitted due to unit mismatch with standard clearance metrics.)

Performance

Travel Speed Low7.4 mph (11.9 km/h)
Travel Speed High8.6 mph (13.8 km/h)
Ground Pressure11 psi (76 kPa)
Bucket Capacity13.7 yd3 (10.5 m3)
Track Shoe Width22.1 in (561 mm)

Service capacities (summary)

Fuel Tank Capacity158.6 gal (600 L)
Hydraulic System Capacity43.6 gal (165 L)

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

Komatsu S6D155-4J(S/N 22144-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
  • Drain water from fuel separator
  • Check air filter restriction indicator
  • Inspect hydraulic hoses for cracks and leaks
Every 250 h
  • Change engine oil and filter
  • Grease all points including boom, stick, bucket, and swing bearing
  • Check fluid levels
  • Inspect air filter outer element
  • Inspect belts and hoses
  • Perform visual walk-around inspection
Every 500 h
  • Replace fuel filter
  • Replace hydraulic return filter
  • Test battery and alternator load
  • Test coolant SCA concentration
  • Collect KOWA oil sample
  • Perform detailed undercarriage visual inspection
Every 1,000 h
  • Replace hydraulic oil
  • Change final drive oil on both sides
  • Inspect turbocharger
  • Check valve adjustment
  • Measure undercarriage wear
  • Inspect structural boom and stick welds
Every 2,000 h
  • Flush and replace coolant
  • Change transmission oil and filter
  • Replace worn belts and hoses
  • Perform comprehensive component evaluation
  • Check KDPF status
  • Torque ROPS bolts

Servicing the S6D155-4J(S/N 22144-UP) beyond the schedule

Predictive Maintenance & Fluid Analysis

Utilize KOWA fluid analysis at every 500-hour interval to monitor wear metals like iron and copper in the S6D155-4J engine oil. Check coolant pH and SCA concentration to prevent scaling in the cylinder head. Monitor hydraulic oil particle count and viscosity to detect pump wear early. Track DEF levels and KDPF differential pressure to manage emissions system efficiency. Analyze transmission oil for gear wear indicators. Use KOMTRAX telematics to correlate load frequency with fluid degradation rates for optimized change intervals.

Corrective & Common Repairs

Address frequent S6D155-4J issues by inspecting the turbocharger KTR130-11F for shaft play and seal leaks. Replace worn piston rings and cylinder liners to restore compression and reduce oil consumption. Check the fuel injection pump for leakage and timing drift. Inspect the water pump impeller and housing for erosion. Replace cracked hydraulic hoses and worn swing bearing pins. Repair or replace faulty engine sensors and EPC system components to resolve fault codes related to fuel pressure and temperature.

Overhaul & Rebuild Points

Perform in-frame overhaul at 15,000–20,000 hours or when compression drops below specification. Replace pistons, rings, liners, and main/rod bearings. Inspect the crankshaft for journal wear and replace if out of tolerance. Recondition or replace the camshaft and valve train components. During out-of-frame rebuilds, inspect the cylinder head for cracks and resurface if necessary. Replace all gaskets, seals, and O-rings. Verify turbocharger clearance and replace if efficiency is compromised. Reassemble with precise torque specifications for the S6D155-4J block.

Seasonal & Environment Servicing

In cold climates, use low-viscosity Komatsu EO engine oil and ensure the coolant mixture provides adequate freeze protection. Pre-heat the engine block and oil pan before starting in sub-zero temperatures. In dusty environments, service the air filter more frequently and inspect the pre-cleaner. In high-altitude applications, verify turbocharger performance and adjust fuel injection timing if power loss occurs. Protect the undercarriage from mud and debris buildup to prevent track tension issues. Drain water from the fuel separator daily in humid conditions to prevent microbial growth.

S6D155-4J(S/N 22144-UP) common service parts

Part numberPart
07281-00197Clamp,(With Pre-Fuel Filter)Check fitment →
600-311-8291Cartridge,Fuel FilterCheck fitment →
6631-51-5000Oil Filter Ass'YCheck fitment →
6127-51-5401Oil Filter Ass'YCheck fitment →
6127-61-2971O-Ring,Oil Cooler ElementCheck fitment →

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

S6D155-4J(S/N 22144-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
CA441Battery voltage too lowWeak battery or charging system faultReplace the battery or alternator and check the voltage regulator
CA442Battery voltage too highAlternator overcharging or regulator failureReplace the alternator or battery and check the voltage regulator
CA122Intake air pressure sensor feedback voltage too highSensor malfunction or wiring shortVerify the intake pressure sensor and wiring
CA123Intake air pressure sensor feedback voltage too lowSensor 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 malfunction or fuel supply issueDiagnose the fuel rail pressure sensor or pump lines
CA234Engine overspeedThrottle calibration error, engine load cycle issue, or operator misuseVerify throttle calibration, engine load cycle, or operator misuse
AA10NXAir cleaner cloggingDirty or blocked air filter elementReplace the air filter
B@BCNSEngine coolant overheatingLow coolant level, blocked radiator, or fan belt failureCheck radiator fins, fan belt, and coolant level

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

S6D155-4J(S/N 22144-UP) attachments & work tools

Bulldozer Blade Configurations

The Komatsu D155W-1, equipped with the S6D155-4J engine (S/N 22144-UP), is fitted with a semi-universal blade. Factory specifications list the blade width at 4.13 m (13.6 ft) and the bucket capacity at 10.5 m³ (13.7 yd³). The blade height is specified at 1.59 m (62.6 in) with a cut height of 0.55 m (22.1 in).

Dozer Undercarriage & Ground Engagement

The D155W-1 utilizes a track shoe width of 546 mm (21.5 in) and a track gauge of 3.96 m (13.0 ft). The machine operates on a planetary gear final drive system with 3 speeds forward and 3 speeds reverse, achieving travel speeds of 11.9 km/h (7.4 mph) and 13.8 km/h (8.6 mph).

Engine Power & Performance

The S6D155-4J engine is a turbocharged 6-cylinder diesel unit with a displacement of 19.2 L (1175 cu in). It generates a gross power output of 239 kW (320 hp) at 1800 rpm. The engine is associated with the D155A-1 and D155W-1 dozer models in the 155 series.

Fluid Capacities & Specifications

The D155W-1 has a fuel tank capacity of 600 L (158.6 gal) and a hydraulic system capacity of 165 L (43.6 gal). Komatsu engineering standards recommend Komatsu EO, TO, and AXO fluids for engine, hydraulic, and powertrain applications respectively, with Super-coolant AF-NAC for the cooling system.

Machine Weight & Dimensions

The operating weight of the D155W-1 is 26,920 kg (59,350 lb). The machine dimensions include a transport length of 8.38 m (27.5 ft) and a transport height of 3.48 m (11.4 ft). The counterweight is integrated into the rear frame structure.

All S6D155-4J(S/N 22144-UP) assemblies by section

Every catalogued assembly group for the Komatsu S6D155-4J(S/N 22144-UP). Open an assembly to preview the parts inside — full OEM part numbers are available in Heavy Parts AI.

Accessory
Komatsu : S6d155-4j(S/N 22144-Up) : Accessory : Air Compressor
02***22Bolt2
02***70Bolt4
02***32Bolt,(With Joy Stick Steering)6
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Komatsu : S6d155-4j(S/N 22144-Up) : Accessory : Air Compressor Drive
01***30Bolt,(Cold Terrain Spec.)2
01***50Bolt2
01***60Bolt (M10-1.50x60)3
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Komatsu : S6d155-4j(S/N 22144-Up) : Accessory : Air Compressor Piping
01***16Bolt,(For Slag Handling)1
01***20Bolt,(Sandy? Dusty Terrain Spec.)1
01***80Bolt,(See Fig.0131)2
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Komatsu : S6d155-4j(S/N 22144-Up) : Accessory : Air Governor
38***-1Screw,Adjusting1
38***-1Seat,Spring2
38***-1Guide,Spring1
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Cooling And Electrical Systems
Komatsu : S6d155-4j(S/N 22144-Up) : Cooling And Electrical Systems : Alternator (20a)
60***60Alternator A. (20a)1
KD***00Collar1
KD***31Rectifier Ass'Y1
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Komatsu : S6d155-4j(S/N 22144-Up) : Cooling And Electrical Systems : Alternator (35a)
60***60Alternator A. (35a),(Cold Weather Spec.)1
KD***00Collar1
KD***72Bracket,Rear1
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Komatsu : S6d155-4j(S/N 22144-Up) : Cooling And Electrical Systems : Alternator (40a) (Extreme Cold Terrain Spec.)
60***10Alternator A. (40a)1
KD***70Sheet2
KD***00Collar1
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Komatsu : S6d155-4j(S/N 22144-Up) : Cooling And Electrical Systems : Alternator And Mounting (20a? 35a? 40a)
01***85Bolt2
01***20Bolt1
01***40Bolt,(Cold Weather Spec.)1
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Komatsu : S6d155-4j(S/N 22144-Up) : Cooling And Electrical Systems : Cooling Fan And Fan Drive
01***20Bolt,(Sandy? Dusty Terrain Spec.)7
01***25Bolt,(Sandy? Dusty Terrain Spec.)2
01***35Bolt, Mounting - Flywheel Housing End2
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Komatsu : S6d155-4j(S/N 22144-Up) : Cooling And Electrical Systems : Corrosion Resistor And Piping
01***20Bolt,(Sandy? Dusty Terrain Spec.)1
01***30Bolt,(For France Noise Suppression)8
01***25Washer,Spring?(Sandy And Dusty Spec.)1
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Komatsu : S6d155-4j(S/N 22144-Up) : Cooling And Electrical Systems : Starting Motor (11kw)
60***61Starting Motor A.,(11kw)1
KD***82Screw,Dish8
KD***60Field Coil Ass'Y1
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Komatsu : S6d155-4j(S/N 22144-Up) : Cooling And Electrical Systems : Starting Motor And Mounting (11kw)
01***25Bolt - Rear Guard Mounting2
01***50Bolt, Radiator To Frame3
01***25Bolt2
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Komatsu : S6d155-4j(S/N 22144-Up) : Cooling And Electrical Systems : Water Pump And Piping
01***16Bolt (Welded)6
01***20Bolt,(Sandy? Dusty Terrain Spec.)4
01***45Bolt,(S6d155-4b)1
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Cylinder Block
Komatsu : S6d155-4j(S/N 22144-Up) : Cylinder Block : Camshaft And Tappet
04***35Key1
61***30Plug, No. 41
61***02Camshaft Ass'Y1
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Komatsu : S6d155-4j(S/N 22144-Up) : Cylinder Block : Crankshaft And Vibration Damper
01***25Bolt - Rear Guard Mounting6
01***36Washer,Radio Controlled Slag Handling6
04***40Key1
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Komatsu : S6d155-4j(S/N 22144-Up) : Cylinder Block : Cylinder Block
01***18Bolt6
01***25Bolt,(Without Auto Priming System)24
01***20Bolt,(Large Capacity Type) (Std)2
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Komatsu : S6d155-4j(S/N 22144-Up) : Cylinder Block : Flywheel And Flywheel Housing
01***25Bolt,(Sandy? Dusty Terrain Spec.)8
01***30Bolt,(For France Noise Suppression)12
01***45Bolt, Mount Bracket4
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Komatsu : S6d155-4j(S/N 22144-Up) : Cylinder Block : Gear Case And Front Support
01***12Bolt,(Without R.P.C.U.)2
01***90Bolt (M10-1.50x90)8
01***40Bolt,(Not Used With Cab)6
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Komatsu : S6d155-4j(S/N 22144-Up) : Cylinder Block : Oil Pan(#22144-23360)
01***20Bolt,(Sandy? Dusty Terrain Spec.)1
01***25Bolt,(Without Auto Priming System)2
01***20Bolt,(Large Capacity Type) (Std)10
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Komatsu : S6d155-4j(S/N 22144-Up) : Cylinder Block : Oil Pan(#23361-28423)
01***20Bolt,(Sandy? Dusty Terrain Spec.)1
01***25Bolt,(Without Auto Priming System)2
01***25Bolt,(Sandy? Dusty Terrain Spec.)2
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Komatsu : S6d155-4j(S/N 22144-Up) : Cylinder Block : Oil Pan(#28424-)
01***20Bolt,(Sandy? Dusty Terrain Spec.)1
01***25Bolt,(Without Auto Priming System)2
01***25Bolt,(Sandy? Dusty Terrain Spec.)2
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Komatsu : S6d155-4j(S/N 22144-Up) : Cylinder Block : Piston And Connecting Rod
61***20Ring,Snap2
61***12Piston Ass'Y6
61***30Piston Ass'Y,(Service Parts)6
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Komatsu : S6d155-4j(S/N 22144-Up) : Cylinder Block : Power Take Off
01***20Bolt,(Large Capacity Type) (Std)6
01***30Bolt,(For France Noise Suppression)6
01***30Bolt,Radio Controlled Slag Handling6
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Cylinder Head
Komatsu : S6d155-4j(S/N 22144-Up) : Cylinder Head : Air Cleaner And Connection
01***25Bolt,(Sandy? Dusty Terrain Spec.)4
01***30Bolt,(For Center Guard)4
01***08Nut, Regular Hexagon (M10-1.50)8
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Komatsu : S6d155-4j(S/N 22144-Up) : Cylinder Head : Air Intake Manifold And Connection
01***20Bolt,(Sandy? Dusty Terrain Spec.)1
01***25Bolt,(Sandy? Dusty Terrain Spec.)4
01***85Bolt, Control Valve Mounting12
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Komatsu : S6d155-4j(S/N 22144-Up) : Cylinder Head : Compression Release
01***30Bolt,(Cold Terrain Spec.)1
01***35Bolt,(Without Auto Priming System)1
01***25Washer,Spring?(Sandy And Dusty Spec.)1
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Komatsu : S6d155-4j(S/N 22144-Up) : Cylinder Head : Cylinder Head
01***30Bolt,(For France Noise Suppression)6
01***30Washer,Spring(Sandy?Dusty Terrain S.)6
07***20Plug2
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Komatsu : S6d155-4j(S/N 22144-Up) : Cylinder Head : Exhaust Manifold And Turbocharger
01***10Bolt18
01***70Bolt2
01***90Bolt2
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Komatsu : S6d155-4j(S/N 22144-Up) : Cylinder Head : Rocker Arm And Housing
01***05Bolt (Kit)22
01***10Bolt, Mount Filler Tube2
01***36Washer,Radio Controlled Slag Handling24
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Komatsu : S6d155-4j(S/N 22144-Up) : Cylinder Head : Rocker Arm Housing Cover
01***22Bolt,(Cold Terrain Spec.)3
01***40Bolt,(For Position Fixing)2
01***25Bolt,(Sandy? Dusty Terrain Spec.)2
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Komatsu : S6d155-4j(S/N 22144-Up) : Cylinder Head : Turbocharger
01***30Bolt4
01***18Bolt6
04***50Screw6
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Komatsu : S6d155-4j(S/N 22144-Up) : Cylinder Head : Water Manifold And Thermostat
01***30Bolt,(For France Noise Suppression)4
01***35Bolt, Mounting - Flywheel Housing End8
01***95Bolt,(For Reversible Fan)2
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Fuel System
Komatsu : S6d155-4j(S/N 22144-Up) : Fuel System : Automatic Timer
61***32Automatic Timer A1
DK***00Washer1
DK***00Flyweight2
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Komatsu : S6d155-4j(S/N 22144-Up) : Fuel System : Fuel Filter And Mounting(#24805-)
07***12Gasket,Mechanical Pump Piping2
07***08Plug,(Without Auto Priming System)1
60***91Cartridge,Fuel Filter2
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Komatsu : S6d155-4j(S/N 22144-Up) : Fuel System : Fuel Filter(#22144-24804)
04***12Wire,Lock2
07***12Gasket,Mechanical Pump Piping2
07***12Gasket,(Without Air Compressor Type) (K2)1
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Komatsu : S6d155-4j(S/N 22144-Up) : Fuel System : Fuel Injection Pump (Feed Pump)(#22144-33406)
DK***20Tappet Ass'Y1
DK***20Pump,Priming1
DK***30Eye,Joint1
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Komatsu : S6d155-4j(S/N 22144-Up) : Fuel System : Fuel Injection Pump (Feed Pump)(#33407-47497)
61***32Joint,Fuel1
DK***20Tappet Ass'Y1
DK***20Pump,Priming1
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Komatsu : S6d155-4j(S/N 22144-Up) : Fuel System : Fuel Injection Pump (Feed Pump)(#47498-)
DK***20Tappet Ass'Y1
DK***20Pump,Priming1
DK***30Eye,Joint1
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Komatsu : S6d155-4j(S/N 22144-Up) : Fuel System : Fuel Injection Pump (Governor)(#22144-47497)
61***02Injection Pump Ass'Y,(See Fig.451)1
61***20Plate? Caution,(French) (Not Shown)1
61***60Plate? Caution,(German) (Not Shown)1
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Komatsu : S6d155-4j(S/N 22144-Up) : Fuel System : Fuel Injection Pump (Governor)(#47498-)
DK***00Gear1
DK***20Lever1
DK***01Governor Ass'Y1
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Komatsu : S6d155-4j(S/N 22144-Up) : Fuel System : Fuel Injection Pump (Pump)
61***02Injection Pump Ass'Y,(See Fig.451)1
61***03Injection Pump Ass'Y1
61***04Injection Pump Ass'Y1
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Komatsu : S6d155-4j(S/N 22144-Up) : Fuel System : Fuel Injection Pump And Piping
01***12Bolt (M8-1.25x12)2
01***20Bolt,(Sandy? Dusty Terrain Spec.)1
01***30Bolt,(Cold Terrain Spec.)8
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Komatsu : S6d155-4j(S/N 22144-Up) : Fuel System : Fuel Injection Pump Drive
01***30Bolt,Radio Controlled Slag Handling6
01***35Bolt - Torque Converter Totransmission Mounting1
01***30Bolt,(Cold Weather Spec.)6
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Komatsu : S6d155-4j(S/N 22144-Up) : Fuel System : Fuel Nozzle
07***12Gasket,Mechanical Pump Piping2
61***04Nozzle Holder Ass'Y1
61***33Nozzle,Fuel1
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Komatsu : S6d155-4j(S/N 22144-Up) : Fuel System : Fuel Nozzle And Spill Pipe
01***25Washer,Spring?(Sandy And Dusty Spec.)3
01***10Washer,See Fig. K4010-12a03
07***12Gasket,Mechanical Pump Piping14
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Komatsu : S6d155-4j(S/N 22144-Up) : Fuel System : Hand Primer
Komatsu : S6d155-4j(S/N 22144-Up) : Fuel System : Solenoid And Mounting(#47498-)
01***16Bolt (Welded)4
01***50Bolt,(For Trimming Dozer)4
01***03Nut; Was 01508-20603, Nut? L.H. Thread,L.H. Thread1
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Lubricating Oil System
Komatsu : S6d155-4j(S/N 22144-Up) : Lubricating Oil System : By-Pass Oil Filter
01***75Bolt,(For 75a Alternator)2
01***15Bolt2
01***36Washer,Radio Controlled Slag Handling4
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Komatsu : S6d155-4j(S/N 22144-Up) : Lubricating Oil System : Camshaft Lubricating Oil Piping
07***10Connector6
61***40Nozzle,Oil12
61***10Pipe2
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Komatsu : S6d155-4j(S/N 22144-Up) : Lubricating Oil System : Lubricating Oil Cooler
01***20Bolt,(Large Capacity Type) (Std)2
01***30Bolt,(For France Noise Suppression)2
01***35Bolt, Mounting - Flywheel Housing End19
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Komatsu : S6d155-4j(S/N 22144-Up) : Lubricating Oil System : Lubricating Oil Filter And Mounting(#22144-24804)
01***20Bolt,(Sandy? Dusty Terrain Spec.)6
01***40Bolt,(Dust And Dirt Protection)6
01***85Bolt, Control Valve Mounting4
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Komatsu : S6d155-4j(S/N 22144-Up) : Lubricating Oil System : Lubricating Oil Filter And Mounting(#24805-28423)
01***40Bolt,(Dust And Dirt Protection)5
01***85Bolt, Control Valve Mounting3
01***36Washer,Radio Controlled Slag Handling8
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Komatsu : S6d155-4j(S/N 22144-Up) : Lubricating Oil System : Lubricating Oil Filter And Mounting(#28424-)
01***40Bolt,(Dust And Dirt Protection)5
01***85Bolt, Control Valve Mounting3
01***36Washer,Radio Controlled Slag Handling8
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Komatsu : S6d155-4j(S/N 22144-Up) : Lubricating Oil System : Lubricating Oil Filter Bracket
01***70Bolt, Spacer2
01***40Bolt,(Dust And Dirt Protection)6
01***80Bolt,(Shim 5 Pieces Over)5
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Komatsu : S6d155-4j(S/N 22144-Up) : Lubricating Oil System : Lubricating Oil Pump(#22144-26422)
01***20Bolt,(Large Capacity Type) (Std)2
01***25Bolt,(Sandy? Dusty Terrain Spec.)2
01***50Bolt - Torque Converter Totransmission Mounting2
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Komatsu : S6d155-4j(S/N 22144-Up) : Lubricating Oil System : Lubricating Oil Pump(#26423-)
01***20Bolt,(Large Capacity Type) (Std)2
01***25Bolt,(Sandy? Dusty Terrain Spec.)2
01***50Bolt - Torque Converter Totransmission Mounting2
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Komatsu : S6d155-4j(S/N 22144-Up) : Lubricating Oil System : Oil Strainer And Piping
01***12Bolt,(Without R.P.C.U.)2
01***14Bolt2
01***22Bolt3
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Komatsu : S6d155-4j(S/N 22144-Up) : Lubricating Oil System : Power Take Off Lubricating Oil Piping
01***22Bolt1
01***30Bolt,(For France Noise Suppression)2
01***30Washer,Spring(Sandy?Dusty Terrain S.)4
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Komatsu : S6d155-4j(S/N 22144-Up) : Lubricating Oil System : Turbocharger Lubricating Oil Piping
01***10Bolt3
01***35Bolt,(Without Auto Priming System)2
01***35Bolt, Mounting - Flywheel Housing End2
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Tool And Kit
Komatsu : S6d155-4j(S/N 22144-Up) : Tool And Kit : Gasket Kit
01***12Washer,Lock3
01***12Washer (K2)4
01***08Washer (K2)1
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S6D155-4J(S/N 22144-UP) serial number reference

The engine serial number plate is located on the left side of the engine block or near the valve cover. The machine PIN plate is typically on the right-hand side of the cab or front frame; the 3-character prefix is the first three letters of the machine model code (e.g., D15, D27).

PrefixIdentifies
D155W-1Bulldozer
D275A-2Crawler Dozer

Frequently asked questions

What engine does the Komatsu S6D155-4J use?

The Komatsu S6D155-4J is a turbocharged, six-cylinder, direct-injection diesel engine. It is part of the 155-series family and was used in D155A and D155W dozers. It produces approximately 320 hp (239 kW) gross power.

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

The operating weight varies by configuration and attachment. For the Komatsu D155A-1 dozer, the operating weight is approximately 59,350 lbs (26,943 kg). Other configurations in the D155 series can range up to 87,083 lbs (39,474 kg).

What engine replaced the S6D155-4J?

The S6D155-4J was succeeded by the S6D170E-2A and S6D170-1L engines in later Komatsu dozer models. These newer engines offer increased displacement and improved emissions compliance for modern Tier 4 and Stage III standards.

What S6D155-4J(S/N 22144-UP) owners discuss

What is the net horsepower rating for the S6D155-4 engine as used in the D155A-1 crawler dozer?
320 hp (239 kW). This rating applies to the turbocharged S6D155-4 configuration found in the D155A-1 series. Variations may exist for other machine applications using the same engine block. Have your dealer verify the specific rating for your machine's serial range and regional emissions package.
What are the common hydraulic behaviors associated with Komatsu excavators using the S6D155-4 series engine?
Komatsu hydraulic systems are generally smooth and fuel-efficient. A common diagnostic pattern is that if all functions (boom, arm, bucket, swing, travel) become slow simultaneously, the issue is likely shared (hydraulic oil, filters, or engine RPM) rather than a single pump failure. If only one function is slow, check the specific cylinder, control valve, or load-holding valve. Weak performance when hot often indicates internal leakage in pumps or motors due to decreased oil viscosity.
What undercarriage and wear patterns are typical for machines powered by this engine series?
Machines in this class (e.g., D155A-1) operate at high weights (approx. 59,350 lb or 26,920 kg) and ground pressure. Common wear items include track pads, bushings, and bearings. Worn bushings lead to noise and vibration; worn bearings cause premature track failure. Track tension must be monitored regularly, as repeated loosening often points to adjuster or component wear. Always check mechanical resistance and track-chain condition before diagnosing hydraulic travel issues.
What electrical or sensor issues are frequently reported by owners of Komatsu equipment with this engine?
Komatsu equipment relies heavily on electronic control systems. Common issues include intermittent starting, dashboard failures, and random shutdowns triggered by faulty sensors or unstable power supplies. Multiple fault codes often stem from battery state, ground connections, or connector integrity rather than individual component failure. Always verify battery load and voltage drop during cranking before replacing starters or sensors.
What are the known engine quirks or maintenance priorities for the S6D155-4 series?
The S6D155-4 is a turbocharged diesel engine. Key maintenance priorities include monitoring the cooling package (radiator, hydraulic oil cooler, charge-air cooler) for debris packing between heat exchangers, which causes overheating during heavy work. Engine power loss under load often stems from air intake restrictions (clogged filters, loose clamps) or fuel delivery issues (water in fuel, clogged filters). The engine is designed for high durability, but hydraulic contamination can lead to premature engine wear if the system fails.
What fluids and specifications are recommended for the S6D155-4 engine and associated systems?
Use Komatsu Genuine Diesel Engine Oil (meeting Komatsu Engineering Standards), Komatsu Hydraulic Oil (TO or equivalent), and Super-coolant AF-NAC. Specific fluid capacities vary by machine configuration (e.g., D155A-1 has a 158.6 gal / 600 L fuel tank and 43.6 gal / 165 L hydraulic tank). Always consult the specific machine's operation and maintenance manual for exact capacities and intervals.
What should be checked when buying a used machine with an S6D155-4J engine (S/N 22144-Up)?
Verify the engine serial number prefix (22144-Up) against the machine's model plate. Check for signs of hydraulic contamination in the engine oil (milky appearance or fuel smell), as Komatsu hydraulic systems share cooling with the engine in some configurations. Inspect the turbocharger for shaft play and housing damage. Test all hydraulic functions cold and hot to identify internal leakage. Check the condition of the undercarriage components (rollers, idlers, track pads) given the machine's weight class. Have your dealer verify the engine's compression and injection timing against factory specs for this serial range.

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

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