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Komatsu S4D95LE-3A-2(S/N 100001-UP)

Maintenance schedule, common problems & OEM parts breakdown

Search live S4D95LE-3A-2(S/N 100001-UP) parts

The Komatsu S4D95LE-3A-2 is a four-cylinder, turbocharged, direct-injection diesel engine belonging to the 95 Series family. It powers compact to mid-size construction equipment, including the PC130 excavator, D37 and D39 dozers, and WA80 wheel loaders. Operating weights for these machines typically range from 9,000 kg to 13,200 kg. Production for this specific serial range (100001-UP) spans the Tier 3/Stage IIIA era, preceding the SAA4D95LE-3A-4AW and SAA4D95LE-5 generations. Configurations vary by application, with power outputs ranging from 66 kW to 78 kW depending on the host machine.

Across the 95 Series lineage, the S4D95LE-3A-2 represents the transition from mechanical fuel systems to electronic control modules, improving fuel efficiency and emissions compliance. The engine matters in the used and parts market because it serves as the powerplant for a high-volume fleet of compact excavators and dozers still in active service. Its widespread use in the PC130 and D37/D39 platforms ensures a robust aftermarket support network for rebuild kits, cylinder components, and turbochargers, making it a critical reference for fleet maintenance and remanufacturing.

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 S4D95LE-3A-2(S/N 100001-UP) specifications

Engine

Model	S4D95LE-3A-2 (Build 1K)
Cylinders	4
Bore	95 mm (3.74 in)
Stroke	115 mm (4.53 in)
Displacement	3.26 L (199 in³)
Aspiration	Turbocharged, air-to-air aftercooled
Emissions Tier	Tier 2
Firing Order	1-2-4-3

Weights

Note	Operating weight, shipping weight, and ground pressure are machine-level specifications. The provided source text contains no weight data for the S4D95LE-3A-2 engine or its host machines.

Dimensions

Note	Transport dimensions, track gauge, and ground clearance are machine-level specifications. The provided source text contains no dimensional data for the S4D95LE-3A-2 engine or its host machines.

Performance

Note	Travel speeds, lift/dig/dump/drawbar figures, and gradeability are machine-level specifications. The provided source text contains no performance data for the S4D95LE-3A-2 engine or its host machines.

Service capacities (summary)

Lubricating oil amount (refill capacity)	7.0 L
Coolant amount (Engine side)	4.5 L
Coolant amount (Total)	10 L

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

Komatsu S4D95LE-3A-2(S/N 100001-UP) maintenance schedule

Service interval	Tasks
Every 10 h	Check engine oil level and condition. Check hydraulic fluid level via sight glass. Check coolant level and ensure cap is secure. Check fuel level and drain water from separator. Check DEF level on Tier 4 machines. Check air filter restriction indicator. Inspect track tension and shoe/pad condition. Inspect hydraulic hoses for cracks and leaks. Check pins, bushings, and attachment points. Clear debris from radiator and oil cooler fins. Check for fluid leaks under the machine. Verify ROPS/FOPS integrity and seat belt. Test horn, backup alarm, and lights. Ensure emergency shutoff is accessible. Start engine and verify gauges and KOMTRAX display are normal. Test all controls for smooth response. Check service and parking brakes.
Every 250 h	Change engine oil and filter. Grease all points (boom, stick, bucket, swing bearing). Check fluid levels. Check air filter outer element. Inspect belts and hoses. Perform visual walk-around inspection.
Every 500 h	Replace fuel filter. Replace hydraulic return filter. Service battery. Test coolant SCA. Take KOWA oil sample. Perform detailed undercarriage inspection.
Every 1,000 h	Take hydraulic oil sample. Check final drive oil. Inspect turbocharger. Take wear measurements. Check valve adjustment. Perform structural inspection.
Every 2,000 h	Change hydraulic oil. Flush and replace coolant. Service transmission. Perform comprehensive component evaluation. Check KDPF (at 4,500 hr intervals).

Servicing the S4D95LE-3A-2(S/N 100001-UP) beyond the schedule

Predictive Maintenance & Fluid Analysis

Utilize Komatsu Oil Wear Analysis (KOWA) at every 500-hour interval to monitor engine oil for wear metals (iron, copper, lead, aluminum) and contaminants like silicon (dirt) and sodium (coolant). Test coolant SCA concentration at 500 hours to maintain proper pH and glycol levels. Check hydraulic oil particle count and viscosity at 1,000 hours. Monitor DEF levels daily on Tier 4 variants. Use Komatsu Genuine Lubricants to ensure additive packages meet engineering standards for the S4D95LE-3A-2 powertrain.

Corrective & Common Repairs

Address fuel system issues by replacing the fuel filter and draining the water separator at 500-hour intervals to protect the high-pressure injection pump. Inspect the turbocharger and air filter outer element at 1,000 hours for debris and restriction. Check belt tension and hose clamps during 250-hour services. Replace worn piston rings and cylinder liners if compression drops or oil consumption increases. Inspect the exhaust manifold for cracks, a common failure point on the 4D95LE family under heavy load.

Overhaul & Rebuild Points

Perform inframe overhauls when cylinder wear exceeds limits or bearing clearances are out of spec. The S4D95LE-3A-2 inframe kit includes cylinder liners, pistons, rings, and connecting rod bearings. Full overhaul kits add main bearings, thrust washers, and camshaft bearings. Major overhauls include valve jobs, valve guides, and valve seats. Verify main and rod bearing sizes (.010,.020,.030,.040 mm) before ordering rebuild components to match the specific engine serial number.

Seasonal & Environment Servicing

In cold climates, check coolant freeze protection and use appropriate viscosity engine oil (e.g., SAE 5W-30 or 10W-30) to ensure cold starts. Drain water from the fuel separator daily in humid or wet conditions to prevent microbial growth. In dusty environments, inspect the air filter restriction indicator more frequently and clean the radiator/oil cooler fins daily to prevent overheating. Ensure the KDPF and SCR systems are maintained according to the 4,500-hour and 9,000-hour schedules for Tier 4 compliance.

S4D95LE-3A-2(S/N 100001-UP) common service parts

Part number	Part	Notes
6206-73-6300	Fuel Filter Ass'Y	Fuel system service	Check fitment →
07000-02135	O-Ring,Hydraulic Oil Filter	Hydraulic service	Check fitment →

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S4D95LE-3A-2(S/N 100001-UP) fault codes & troubleshooting

Code	Meaning	Likely cause	What to do
CA115	Engine crankshaft speed sensor and backup speed sensor failure	Faulty speed sensor, broken wiring harness, or corroded connector at the sensor pin	Replace the speed sensor and verify voltage at the pin connector
CA111	Internal engine controller fault	Electronic Control Module (ECM) internal failure	Replace or reprogram the ECM
CA451	Common rail pressure sensor feedback value too high	Malfunction in the rail pressure sensor or actual overpressure condition	Diagnose the fuel rail pressure sensor or check pump lines
CA452	Common rail pressure sensor feedback value too low	Sensor malfunction or fuel supply issue	Diagnose the fuel rail pressure sensor or check pump lines
CA122	Intake air pressure sensor feedback voltage too high	Faulty intake pressure sensor or wiring issue	Verify the intake pressure sensor and wiring
CA123	Intake air pressure sensor feedback voltage too low	Sensor short or airflow restriction	Check for a sensor short or an airflow restriction
CA153	Intake air temperature sensor feedback voltage too high	Faulty Intake Air Temperature (IAT) sensor	Replace or test the IAT sensor
CA154	Intake air temperature sensor feedback voltage too low	Faulty Intake Air Temperature (IAT) sensor	Replace or test the IAT sensor
CA441	Battery voltage too low	Weak battery, faulty alternator, or voltage regulator issue	Replace the alternator or battery; check the voltage regulator
CA442	Battery voltage too high	Faulty alternator or voltage regulator	Replace the alternator or battery; check the voltage regulator

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

S4D95LE-3A-2(S/N 100001-UP) attachments & work tools

Excavator Buckets

The S4D95LE-3A-2 engine powers compact excavators such as the PC60-7, PC75UU-3, and PC78US-6. Factory specifications for these models list standard bucket capacities ranging from 0.26 to 0.60 cubic meters, with operating weights between 12,900 and 13,200 kg for the PC130 series which shares the engine family.

Dozer Blades

Compact dozers like the D37 and D39 utilize the SAA4D95LE engine variant. The D37 is equipped with a blade capacity of 1.91 cubic meters and an operating weight of 9,000 kg. The D39 features a larger blade capacity of 2.21 cubic meters with an operating weight of 10,010 kg.

Coupler Systems

Factory operation and maintenance manuals for the 95-2 Series excavators specify the use of a push-pull type coupler. Maintenance procedures require releasing residual pressure from the hydraulic tank before disassembling or connecting the coupler mechanism.

Hydraulic and Engine Fluids

Komatsu engineering standards specify Komatsu EO diesel engine oil, TO powertrain oil, and AXO axle oil. Hydraulic systems require Komatsu HO hydraulic oil, and cooling systems utilize Super-coolant AF-NAC. The 95-2 Series shop manual notes a lubricating oil refill capacity of 7.0 liters and a total coolant amount of 10 liters.

All S4D95LE-3A-2(S/N 100001-UP) assemblies by section

Every catalogued assembly group for the Komatsu S4D95LE-3A-2(S/N 100001-UP). Open an assembly to preview the parts inside — full OEM part numbers are available in Heavy Parts AI.

Engine

Komatsu : S4d95le-3a-2(S/N 100001-Up) : Engine : Air Compressor Mounting (Bracket)

01***30	Bolt - Lower Oil Cooler Outlet Tubemounting	2
01***50	Bolt,(See Fig.A4010-C3w6)	1
08***10	Bracket, Bucket Position Sensor	1
21***72	Bracket	1

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Komatsu : S4d95le-3a-2(S/N 100001-Up) : Engine : Air Intake

01***65	Bolt, Mount Tube To Divider Valve	2
01***75	Bolt (M10-1.50x75)	6
09***50	Liquid Gasket, Lg-7, 150g	0
62***32	Manifold,Air Intake	1

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Komatsu : S4d95le-3a-2(S/N 100001-Up) : Engine : Air Intake Connector

01***25	Bolt, Mount Engine Oil Drain To Fuel Tank	2
01***30	Bolt - Lower Oil Cooler Outlet Tubemounting	2
07***09	Clamp,(See Fig. K0210-16a0)	2
21***42	Bracket	1

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Komatsu : S4d95le-3a-2(S/N 100001-Up) : Engine : Alternator (25a) (With Non Hardening Pulley)

(6***0)

Alternator A. (25a),(See Fig.A6010-B1e1)

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Komatsu : S4d95le-3a-2(S/N 100001-Up) : Engine : Alternator (25a) (With Non Hardening Pulley) (Inner Parts)

60***20	Alternator A. (25a),(With Non Hardening Pulley)	1
KD***57	Bearing,Ball? Front	1
KD***11	Rear Bracket Ass'Y	1
KD***90	Nut	2

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Komatsu : S4d95le-3a-2(S/N 100001-Up) : Engine : Alternator Mounting (For 25a Alternator)

01***35	Bolt,(Cold Weather Spec.)	1
01***25	Bolt - Relay Mounting	3
01***60	Bolt, Mounting	1
01***95	Bolt	1

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Komatsu : S4d95le-3a-2(S/N 100001-Up) : Engine : Camshaft And Gear

01***20	Bolt,(Forwarded Individually Parts)	2
04***16	Fitting Wedge	1
62***31	Thrust Washer	1
62***21	Gear,Camshaft	1

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Komatsu : S4d95le-3a-2(S/N 100001-Up) : Engine : Cooling Fan

60***20

Fan,Cooling

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Komatsu : S4d95le-3a-2(S/N 100001-Up) : Engine : Cooling Fan Bolt

01***20

Bolt, Hose Clamps (Inlet And Return Line Hoses)

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Komatsu : S4d95le-3a-2(S/N 100001-Up) : Engine : Cooling Fan Spacer Bolt

01***55

Screw

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Komatsu : S4d95le-3a-2(S/N 100001-Up) : Engine : Crank Pulley (Non Hardening)

01***45	Bolt,Nylock	1
61***31	Plate	1
62***21	Pulley,Non Hardening	1

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Komatsu : S4d95le-3a-2(S/N 100001-Up) : Engine : Crankshaft

62***00	Main Metal Ass'Y	5
62***00	Thrust Metal Ass'Y	1
62***00	Main Metal Ass'Y	5
62***00	Thrust Metal Ass'Y	1

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Komatsu : S4d95le-3a-2(S/N 100001-Up) : Engine : Cylinder Block

04***20	Pin,Dowel (Welded)	2
04***28	Pin, Dowel - Transmission Case, Pin-Dowel	2
04***08	Adapter Sleeves	6
07***08	Plug,(D65ex?Px)	4

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Komatsu : S4d95le-3a-2(S/N 100001-Up) : Engine : Cylinder Block Gasket Kit

01***12	Washer,Lock (Noise Suppression Spec.) (K2)	1
07***18	O-Ring,(See Fig.1601-29?1602-17)	1
07***20	O-Ring,Relief Valve	1
07***65	O-Ring,Injection Pump Case	1

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Komatsu : S4d95le-3a-2(S/N 100001-Up) : Engine : Cylinder Block Plug

07***16

Plug,(Without Air Compressor Type)

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Komatsu : S4d95le-3a-2(S/N 100001-Up) : Engine : Cylinder Head

02***04	Plug, Pipe	1
07***08	Plug, Expansion	4
07***10	Plug, Expansion	9
07***16	Plug,(Without Oil Cooler)	3

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Komatsu : S4d95le-3a-2(S/N 100001-Up) : Engine : Cylinder Head Gasket Kit

07***40	O-Ring,Water Pump Mount	1
07***15	Gasket,(Hd325?Pc750?800?1800) (A5010)	2
07***12	Washer, Gasket,(Without Thermo Sensor) (K1)	1
08***14	Band,(For Additional Fuel Strainer)	1

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Komatsu : S4d95le-3a-2(S/N 100001-Up) : Engine : Dust Indicator

08***01

Indicator,Dust (Japanese-English)

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Komatsu : S4d95le-3a-2(S/N 100001-Up) : Engine : Exhaust Connector

01***25	Stud	4
01***35	Bolt,R.H. (For Add. Air Compressor)	2
62***50	Nut	4
62***90	Connector	1

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Komatsu : S4d95le-3a-2(S/N 100001-Up) : Engine : Exhaust Manifold

01***45	Bolt, Bracket Mounting	8
07***08	Plug,(For W/O. Corrosion Resistor)	1
62***40	Manifold,Exhaust	1
62***11	Gasket	1

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Komatsu : S4d95le-3a-2(S/N 100001-Up) : Engine : Fan Belt (For 25a Alternator)

04***47

V-Belt,(With 25a Alternator)

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Komatsu : S4d95le-3a-2(S/N 100001-Up) : Engine : Fan Spacer

62***50

Spacer

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Komatsu : S4d95le-3a-2(S/N 100001-Up) : Engine : Flywheel

01***30	Bolt	6
61***61	Washer, Plain (14mm)	6
62***93	Gear,Ring	1
62***72	Flywheel Ass'Y	1

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Komatsu : S4d95le-3a-2(S/N 100001-Up) : Engine : Flywheel Housing

01***30	Bolt - Lower Oil Cooler Outlet Tubemounting	11
07***15	Plug,(Used When Without Heater)	1
61***32	Seal? Rear (K2)	1
62***30	Housing,Flywheel	1

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Komatsu : S4d95le-3a-2(S/N 100001-Up) : Engine : Front Cover

01***16	Bolt, Mount Solenoid Valve	2
01***55	Screw	13
01***70	Screw	2
01***06	Nut	2

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Komatsu : S4d95le-3a-2(S/N 100001-Up) : Engine : Front Hanger

01***20	Bolt, Hose Clamps (Inlet And Return Line Hoses)	2
62***30	Hanger,Front (W/O Corrosion Resistor)	1

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Komatsu : S4d95le-3a-2(S/N 100001-Up) : Engine : Fuel Filter

01***65	Bolt, Mount Tube To Divider Valve	2
07***12	Gasket,(Without Air Compressor Type) (K1)	6
07***14	Bolt,Joint	2
07***22	Hose,(See Fig.0411-12)	1

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Komatsu : S4d95le-3a-2(S/N 100001-Up) : Engine : Fuel Injection Piping

01***12	Bolt,(See Fig. K0210-16a0)	2
01***25	Screw	2
62***10	Tube,Injection? No.1	1
62***20	Tube,Injection? No.2	1

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Komatsu : S4d95le-3a-2(S/N 100001-Up) : Engine : Fuel Injection Pump

62***50

Injection Pump Ass'Y

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Komatsu : S4d95le-3a-2(S/N 100001-Up) : Engine : Fuel Injection Pump Lubricator

07***12	Gasket,(Without Air Compressor Type) (K2)	2
07***10	Screw, Banjo Connector (M10-1.25x20)	1
62***30	Pipe,Oil	1
62***50	Connector	1

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Komatsu : S4d95le-3a-2(S/N 100001-Up) : Engine : Fuel Injection Pump Mounting

01***20	Bolt	1
01***35	Grub Screw	4
01***12	Bolt,(With Speedometer)	1
01***20	Bolt, Hose Clamps (Inlet And Return Line Hoses)	1

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Komatsu : S4d95le-3a-2(S/N 100001-Up) : Engine : Fuel Return

07***00	Clip	7
62***81	Cap,(See Fig.0421-17)	1
62***00	Hose,(See Fig.0421-14? 0421a-14)	3

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Komatsu : S4d95le-3a-2(S/N 100001-Up) : Engine : Glow Plug

60***70	Glow Plug	4
62***20	Wire	1
62***10	Lead	3

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Komatsu : S4d95le-3a-2(S/N 100001-Up) : Engine : Head Cover

04***50	Screw	4
61***20	Screw	3
61***30	Washer,(B)	3
61***42	Packing,Cylinder Head Cover	3

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Komatsu : S4d95le-3a-2(S/N 100001-Up) : Engine : Head Cover Related Parts

01***20	Bolt,(Forwarded Individually Parts)	1
01***20	Bolt, Hose Clamps (Inlet And Return Line Hoses)	1
04***10	Clip,(See Fig.0311a Or 0321)	1
07***09	Clamp, Hose	2

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Komatsu : S4d95le-3a-2(S/N 100001-Up) : Engine : Heater Signal

60***61

Signal,Heater

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Komatsu : S4d95le-3a-2(S/N 100001-Up) : Engine : Idler Gear

01***70	Bolt,(For 75a Alternator)	1
04***12	Pin,Spring (See Fig.0201)	1
62***31	Shank	1
62***41	Bushing	1

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Komatsu : S4d95le-3a-2(S/N 100001-Up) : Engine : Injection Nozzle

01***35	Bolt, Mount Bracket To Floor	4
62***10	Nozzle Holder	1
62***10	Carrier	4
62***30	Washer	4

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Komatsu : S4d95le-3a-2(S/N 100001-Up) : Engine : Muffler

01***20	Bolt,(Forwarded Individually Parts)	4
01***25	Bolt, Mount Engine Oil Drain To Fuel Tank	4
01***06	Nut	2
62***60	Bracket	1

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Komatsu : S4d95le-3a-2(S/N 100001-Up) : Engine : Oil Filter

01***25	Bolt - Relay Mounting	14
01***35	Bolt, Cover	1
01***80	Screw	2
01***40	Bolt,(Shim 3-Piece)	4

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Komatsu : S4d95le-3a-2(S/N 100001-Up) : Engine : Oil Level Gauge

01***14	Bolt,(W/Joy Stick Str.)(W/O Heater)	1
01***65	Bolt, Mount Tube To Divider Valve	1
04***08	Clip	1
61***20	Collar	1

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Komatsu : S4d95le-3a-2(S/N 100001-Up) : Engine : Oil Pan And Suction Tube

01***14	Bolt,(W/Joy Stick Str.)(W/O Heater)	22
01***16	Bolt, Mount Solenoid Valve	2
01***20	Bolt,(Forwarded Individually Parts)	2
01***23	Washer, Wiring Harness Mounting Bracket	3

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Komatsu : S4d95le-3a-2(S/N 100001-Up) : Engine : Oil Pressure Switch

08***05

Switch,Engine Oil Pressure

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Komatsu : S4d95le-3a-2(S/N 100001-Up) : Engine : Oil Pump

01***16	Bolt, Mount Solenoid Valve	4
01***25	Bolt - Relay Mounting	1
62***01	Cover Ass'Y	1
62***10	Valve	1

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Komatsu : S4d95le-3a-2(S/N 100001-Up) : Engine : Piston

04***12	Ring, Snap	8
62***10	Pin,Piston	4
62***01	Connecting Rod Ass'Y	4
62***30	Bushing	1

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Komatsu : S4d95le-3a-2(S/N 100001-Up) : Engine : Plug

07***10

Plug

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Komatsu : S4d95le-3a-2(S/N 100001-Up) : Engine : Rear Hanger

62***10

Hanger,Rear

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Komatsu : S4d95le-3a-2(S/N 100001-Up) : Engine : Rocker Arm

01***65	Bolt,(For Alternator Bracket Mount)	5
62***20	Spring	3
62***10	Arm,Rocker	8
62***10	Bracket	1

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Komatsu : S4d95le-3a-2(S/N 100001-Up) : Engine : Solenoid

01***14	Bolt - Plate Mounting	2
01***90	Bolt,(For Large Fan)	1
01***15	Bolt	2
01***03	Nut, L. H. Thread	1

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Komatsu : S4d95le-3a-2(S/N 100001-Up) : Engine : Spare Parts

04***47	V-Belt,(With 25a Alternator)	1
07***16	Gasket,(For Pc750-6) (See Fig.A2110)	1
60***10	Cartridge,Engine Oil	1
60***60	Cartridge,Fuel	1

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Komatsu : S4d95le-3a-2(S/N 100001-Up) : Engine : Starting Motor Mounting (3.0kw)

01***25	Bolt, Mount Engine Oil Drain To Fuel Tank	2
01***35	Bolt,R.H. (For Add. Air Compressor)	2
04***10	Clip,(With Accumulator)	1
21***21	Bracket	1

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Komatsu : S4d95le-3a-2(S/N 100001-Up) : Engine : Tacho Drive Cover

01***16	Bolt, Mounting Transmission Control Switch	2
07***50	Ring, Seal - Between Sections	1
61***51	Plate, Cover	1

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Komatsu : S4d95le-3a-2(S/N 100001-Up) : Engine : Tamper Proof Kit

60***10	Screw	1
62***20	Plate	1

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Komatsu : S4d95le-3a-2(S/N 100001-Up) : Engine : Tappet

62***10	Tappet	8
62***10	Tappet Rod	8

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Komatsu : S4d95le-3a-2(S/N 100001-Up) : Engine : Turbocharger (Inner Parts)

62***50	Turbocharger Ass'Y,(See Fig.A1530-B0a2)	1
62***20	Housing,Compressor	1
62***10	Housing,Turbine	1
62***30	Actuator	1

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Komatsu : S4d95le-3a-2(S/N 100001-Up) : Engine : Turbocharger Lubricati0n Unit

01***16	Bolt, Mounting Transmission Control Switch	2
01***14	Bolt,(W/Joy Stick Str.)(W/O Heater)	2
01***20	Bolt,(Forwarded Individually Parts)	1
04***93	Ball,Steel	1

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Komatsu : S4d95le-3a-2(S/N 100001-Up) : Engine : Turbocharger Oil Piping

01***25	Stud	4
62***50	Nut	4
62***80	Gasket,Turbocharger Gasket	1
62***50	Turbocharger Ass'Y,(See Fig.A1530-B0a2)	1

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Komatsu : S4d95le-3a-2(S/N 100001-Up) : Engine : Water Connector

01***20	Bolt,(Forwarded Individually Parts)	2
62***30	Connector,Water Outlet	1

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Komatsu : S4d95le-3a-2(S/N 100001-Up) : Engine : Water Pump

01***16	Screw	5
01***55	Screw	3
07***40	O-Ring,Water Pump Mount	1
21***20	Nipple	1

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Komatsu : S4d95le-3a-2(S/N 100001-Up) : Engine : Water Pump Pulley (Non Hardening Pulley)

62***51

Pulley?Non Hardening,(With Tension Pulley)

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Frequently asked questions

What is the engine model?

Komatsu S4D95LE-3A-2 (Build 1K), S/N 100001-UP.

What is the operating weight of the machines it powers?

Varies by configuration/series. The PC130 weighs 12,900-13,200 kg. The D37 weighs 9,000 kg. The D39 weighs 10,010 kg.

What replaced it?

The SAA4D95LE-3A-4AW and SAA4D95LE-5 engines replaced the S4D95LE-3A-2 in later production runs.

What S4D95LE-3A-2(S/N 100001-UP) owners discuss

What is the cylinder liner configuration for the S4D95LE-3A-2 engine, and what are the implications for block machining?

The S4D95LE-3A-2 engine utilizes a parent bore design with no factory-installed cylinder liners. The block is a solid cast iron structure. When the bore is worn beyond standard oversize piston limits, the block must be machined to accept aftermarket sleeves. This process requires precise counterbore chamfering at the correct angle to prevent sleeve flange cracking. The cylinder skirt wall at the bottom of the bore is thin; machining for sleeves reduces this wall thickness further, requiring careful inspection to ensure structural integrity. Oversize pistons are the primary repair method until the bore limit is reached. (varies by configuration/series). Have your dealer verify block machining specifications before proceeding with sleeve installation to ensure proper clearances and wall thickness safety margins.

What are the common hydraulic behaviors and failure patterns associated with Komatsu excavators using this engine family?

Komatsu hydraulic systems are generally smooth and fuel-efficient but exhibit specific wear patterns. A common diagnostic pattern is hydraulic weakness that appears only when the oil is hot, indicating internal leakage in pumps, control valves, or motors that is masked by higher viscosity when cold. If all functions slow simultaneously, check the hydraulic oil level, filter condition, and engine RPM under load before assuming pump failure. If only one function is slow, focus on the specific circuit, cylinder leakage, or control valve spool. The hydraulic pump and engine are closely coupled; pump failure often precedes or accompanies engine stress. Early Dash-6 series machines had known valve problems, particularly on smaller excavators like the PC120 and PC150. (varies by configuration/series).

What undercarriage and wear patterns are typical for machines powered by the S4D95LE-3A-2?

Machines in this class often exhibit undercarriage wear that coincides with major component failures. Track tension must be monitored regularly, as repeated loosening indicates adjuster or component wear. Mud or debris packed into the undercarriage can cause uneven track speed and pulling. The line is often described as wearing out complete machines simultaneously rather than gradually, contributing to lower resale values. If the hydraulic pump fails, the engine is often not far behind due to the high load demands. (varies by configuration/series).

What are the common electrical and sensor issues reported for Komatsu excavators with this engine?

Komatsu excavators rely heavily on electronic control systems. A single faulty sensor or unstable power supply can trigger multiple warning signals. Owners report intermittent starting, dashboard failures, and random shutdowns. These issues often stem from poor battery connections, corroded chassis grounds, or unstable voltage during cranking. A battery may show acceptable voltage at rest but collapse under starter load. Intermittent faults are often linked to connector integrity and ground points rather than component failure. (varies by configuration/series).

What are the known engine quirks and performance issues for the S4D95LE-3A-2 series?

Engine performance issues dominate serious problem lists, including power loss under load, increased fuel usage, and overheating. Power loss during heavy digging often points to airflow restriction (clogged air filter, damaged charge-air hoses) or fuel delivery issues (clogged filters, water in fuel) rather than internal engine failure. Overheating is frequently caused by debris packed between the radiator, hydraulic oil cooler, and charge-air cooler, rather than coolant loss. The engine is robust but sensitive to contamination and extended service intervals. Low-quality fuel accelerates injector and fuel system wear. (varies by configuration/series).

What fluids and specifications are recommended for the S4D95LE-3A-2 engine and hydraulic system?

Komatsu recommends using fluids that meet Komatsu Engineering Standards. For the engine, use Komatsu Diesel Engine Oil (EO series) or equivalent API CD/CF specifications. For the hydraulic system, use Komatsu Hydraulic Oil (HO series) or equivalent ISO VG46 HL/HLP. For the final drive and swing gearcase, use Komatsu Powertrain Oil (TO series) or equivalent API CD. Coolant should be Komatsu Super Coolant AF-NAC or equivalent ethylene glycol-based coolant meeting JIS K 2234-1987 standards. Using incorrect fluid specifications can accelerate wear and void warranties. (varies by configuration/series).

What specific items should be checked when buying a used machine with the S4D95LE-3A-2 engine?

When purchasing a used machine, verify the exact serial number to confirm the engine build and configuration. Check for signs of coolant entering the combustion chamber or oil, which may indicate head gasket or sleeve sealing issues. Inspect the hydraulic system for cold vs. hot performance differences. Test all electrical functions for intermittent faults or dashboard warnings. Verify the condition of the undercarriage and track tension. Ensure the cooling package is clean and free of packed debris. Confirm that the engine starts reliably without excessive cranking or voltage drop. Review maintenance records for adherence to Komatsu Care intervals. (varies by configuration/series). Have your dealer verify the engine serial number and hydraulic pressure specifications against the factory spec sheet for this exact serial range.

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

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