Komatsu 4D95S-W-1G-T(S/N 23318-UP (FOR TRIMMING DOZER))
Maintenance schedule, common problems & OEM parts breakdown
The Komatsu 4D95S-W-1G-T is a 4-cylinder, water-cooled, turbocharged diesel engine designed for the GD85A and GD105A trimming dozer series. This engine family powers mid-size crawler dozers in the 85 to 105 horsepower class, with operating weights typically ranging from 9,000 to 12,000 kg depending on the specific dozer configuration and attachment package. The 4D95S series succeeded earlier 4D94 and 4D95 non-turbo variants, offering higher torque and fuel efficiency for heavy earthmoving and fine grading applications. Configurations include standard, wide-track (LGP), and specialized trimming setups, with the 'W' denoting water-cooled and 'T' indicating turbocharging. Production spans multiple generations, with the 4D95S-W-1G-T specifically covering serial numbers 23318 and up for the trimming dozer application.
Across the 4D95S generation, Komatsu refined the fuel injection system and turbocharger mapping to meet evolving emissions standards while maintaining the robust, simple mechanical architecture that defines the series. The 4D95S-W-1G-T variant is critical in the used and parts market because it serves as the powerplant for high-demand trimming dozers that operate in confined spaces and require precise blade control. Unlike larger mining engines, the 4D95S is widely supported by aftermarket rebuild kits and generic components, making it a cost-effective choice for fleet owners. Its prevalence in the GD series means that parts availability remains strong, and its relatively compact size simplifies engine removal and installation compared to larger inline-six units.
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 4D95S-W-1G-T(S/N 23318-UP (FOR TRIMMING DOZER)) specifications
Engine
| Model | 4D95S-W-1G-T |
| Series | 95 Series |
| Cylinders | 4 |
| Displacement | 3.26 L (198.9 cu in) |
| Bore | 95 mm (3.74 in) |
| Stroke | 115 mm (4.53 in) |
| Gross Power | 137 hp (102 kW) |
| Net Power | 137 hp (102 kW) |
| Emissions Tier | Tier 4 Final / EU Stage V |
Weights
| Operating Weight | Not documented for this exact serial range — verify with your dealer |
| Shipping Weight | Not documented for this exact serial range — verify with your dealer |
| Ground Pressure | Not documented for this exact serial range — verify with your dealer |
Dimensions
| Transport Length | Not documented for this exact serial range — verify with your dealer |
| Transport Width | Not documented for this exact serial range — verify with your dealer |
| Transport Height | Not documented for this exact serial range — verify with your dealer |
| Track Gauge | Not documented for this exact serial range — verify with your dealer |
| Ground Clearance | Not documented for this exact serial range — verify with your dealer |
Performance
| Travel Speed | Not documented for this exact serial range — verify with your dealer |
| Gradeability | Not documented for this exact serial range — verify with your dealer |
| Drawbar Pull | Not documented for this exact serial range — verify with your dealer |
Service capacities (summary)
| Fuel Tank | Not documented for this exact serial range — verify with your dealer |
| Hydraulic System | Not documented for this exact serial range — verify with your dealer |
| Engine Oil | Not documented for this exact serial range — verify with your dealer |
| Cooling System | Not documented for this exact serial range — verify with your dealer |
Values vary by configuration, region, and serial range — confirm against your machine before planning transport or lifts.
Komatsu 4D95S-W-1G-T(S/N 23318-UP (FOR TRIMMING DOZER)) maintenance schedule
| Service interval | Tasks |
|---|---|
| Every 10 h |
|
| Every 250 h |
|
| Every 500 h |
|
| Every 1,000 h |
|
| Every 2,000 h |
|
Servicing the 4D95S-W-1G-T(S/N 23318-UP (FOR TRIMMING DOZER)) beyond the schedule
Predictive Maintenance & Fluid Analysis
Utilize KOWA fluid analysis at every 500-hour interval to monitor engine wear metals (iron, copper, lead) and contaminants (silicon, sodium). Check coolant SCA concentration at 500 hours to prevent liner cavitation and corrosion. Monitor hydraulic oil particle count and viscosity to detect pump wear early. Inspect turbocharger shaft play and boost pressure consistency during 1000-hour services. Track fuel dilution and soot levels in engine oil to determine optimal drain intervals based on actual operating conditions rather than fixed hours.
Corrective & Common Repairs
Address common 4D95S-W-1G-T issues by inspecting piston rings and cylinder liners for wear, especially if blue smoke or high oil consumption is observed. Check injector nozzles for coking or leakage, which can cause hard starting or rough idle. Inspect the turbocharger housing for cracks and the intercooler for blockages that reduce power. Verify fuel lift pump operation and replace the fuel filter if water contamination is detected. Replace worn camshaft bearings and valve guides if compression drops below specification or valve clearance becomes unadjustable.
Overhaul & Rebuild Points
Plan an in-frame overhaul when compression loss exceeds 20% or oil consumption reaches 1 liter per 10 hours. Replace cylinder liners, pistons, and rings as a set if bore out-of-round exceeds 0.05 mm. Inspect the crankshaft for journal wear and replace if diameter is below minimum specification. Replace all main and rod bearings during overhaul, ensuring proper clearance. Resurface the cylinder head if warpage exceeds 0.10 mm. Verify valve seat integrity and replace seats if pitting or burning is evident.
Seasonal & Environment Servicing
In cold climates, use low-viscosity engine oil and ensure the coolant mixture provides adequate freeze protection. Pre-heat the engine block before starting in temperatures below -10°C. In dusty environments, check the air filter restriction indicator frequently and clean the outer element more often. Inspect the radiator and oil cooler fins daily for debris buildup that restricts airflow. In high-humidity areas, check the fuel water separator daily to prevent microbial growth and injector corrosion. Grease all pivot points more frequently in abrasive conditions.
4D95S-W-1G-T(S/N 23318-UP (FOR TRIMMING DOZER)) common service parts
| Part number | Part | Notes | |
|---|---|---|---|
| 07281-00197 | Clamp,(With Pre-Fuel Filter) | Fuel system service | Check fitment → |
| 600-311-1190 | Plate? Caution,Fuel Filter | Fuel system service | Check fitment → |
| 600-311-6220 | Cartridge,Fuel Filter | Fuel system service | Check fitment → |
| 600-311-9600 | Fuel Filter Ass'Y | Fuel system service | Check fitment → |
| 600-311-7440 | Cartridge,Fuel Filter | Fuel system service | Check fitment → |
Always confirm against your machine's serial number — cross-check any part in Heavy Parts AI before ordering.
4D95S-W-1G-T(S/N 23318-UP (FOR TRIMMING DOZER)) fault codes & troubleshooting
| Code | Meaning | Likely cause | What to do |
|---|---|---|---|
| CA115 | Engine crankshaft speed sensor failure | Broken sensor, wiring issue, or connector corrosion | Replace the speed sensor and verify voltage at the pin connector |
| CA441 | Battery voltage too low | Weak battery or charging system failure | Replace the battery or alternator and check the voltage regulator |
| CA442 | Battery voltage too high | Faulty voltage regulator or alternator | Replace the alternator or battery and check the voltage regulator |
| CA122 | Intake air pressure sensor high voltage | Sensor malfunction or wiring short | Verify the intake pressure sensor and wiring |
| CA123 | Intake air pressure sensor low voltage | Sensor short or airflow restriction | Check for a sensor short or an airflow restriction |
| CA451 | Common rail pressure sensor feedback value too high | Malfunction in the rail sensor or actual overpressure condition | Diagnose the fuel rail pressure sensor or pump lines |
| CA452 | Common rail pressure sensor feedback value too low | Sensor failure or fuel supply issue | Diagnose the fuel rail pressure sensor or pump lines |
| CA234 | Engine overspeed | Throttle calibration error, engine load cycle issue, or operator misuse | Verify throttle calibration, engine load cycle, or operator misuse |
| AA10NX | Air cleaner clogging | Dirty or blocked air filter element | Replace the air filter |
| AB00KE | Charge voltage low | Alternator failure or loose belt | Replace the alternator or tighten the belt |
Codes and remedies are general guidance for this model family — always confirm with diagnostic tooling and your dealer before major repairs.
4D95S-W-1G-T(S/N 23318-UP (FOR TRIMMING DOZER)) attachments & work tools
Main Work-Tool Families
The 4D95S-W-1G-T engine is designated for Trimming Dozers, typically mounted on GD-series motor graders. Standard work tools include the moldboard blade, angle blade, and ripper assemblies for earthmoving and grading.
Coupler/Mounting Systems
The blade and ripper are mounted to the front frame and rear chassis of the GD-series grader using fixed pivot pins and hydraulic cylinders. No quick-attach coupler system is standard for this engine's application class.
Hydraulic Kit/Arrangement Notes
The 4D95S-W-1G-T engine drives the machine's hydraulic pump to operate the blade lift, tilt, and angle cylinders. Auxiliary hydraulics for tool attachment are not specified for this engine variant in the source data.
Notable Factory Configurations/Guarding
The engine is configured for the Trimming Dozer application with specific air intake and exhaust manifold mounting points for serial number 23318 and up. Factory guarding includes standard engine compartment guards and radiator protection as per the GD-series grader spec sheet.
All 4D95S-W-1G-T(S/N 23318-UP (FOR TRIMMING DOZER)) assemblies by section
Every catalogued assembly group for the Komatsu 4D95S-W-1G-T(S/N 23318-UP (FOR TRIMMING DOZER)). Open an assembly to preview the parts inside — full OEM part numbers are available in Heavy Parts AI.
Cooling System
Komatsu : 4d95s-W-1g-T(S/N 23318-Up (For Trimming Dozer)) : Cooling System : Water Pump And Cooling Fan
| 01***16 | Screw | 5 |
| 01***25 | Bolt - Relay Mounting | 2 |
| 01***20 | Screw | 2 |
Cylinder Block
Komatsu : 4d95s-W-1g-T(S/N 23318-Up (For Trimming Dozer)) : Cylinder Block : Camshaft And Tappet
| 01***20 | Screw | 2 |
| 04***16 | Fitting Wedge | 1 |
| 62***31 | Thrust Washer | 1 |
Komatsu : 4d95s-W-1g-T(S/N 23318-Up (For Trimming Dozer)) : Cylinder Block : Crankshaft
| 61***20 | Bolt | 1 |
| 62***00 | Crankshaft Ass'Y | 1 |
| 62***00 | Main Metal Ass'Y | 5 |
Komatsu : 4d95s-W-1g-T(S/N 23318-Up (For Trimming Dozer)) : Cylinder Block : Cylinder Block
| 01***55 | Bolt, Mount Tube To Switch Pump | 8 |
| 01***16 | Screw | 1 |
| 01***20 | Screw | 2 |
Komatsu : 4d95s-W-1g-T(S/N 23318-Up (For Trimming Dozer)) : Cylinder Block : Flywheel And Flywheel Housing
| 01***30 | Bolt | 6 |
| 01***30 | Bolt - Lower Oil Cooler Outlet Tubemounting | 11 |
| 01***45 | Bolt, Bracket Mounting | 8 |
Komatsu : 4d95s-W-1g-T(S/N 23318-Up (For Trimming Dozer)) : Cylinder Block : Front Cover And Gear
| 01***10 | Bolt | 1 |
| 01***70 | Bolt,(For 75a Alternator) | 1 |
| 01***20 | Bolt,(With Tachometer Outlet) | 8 |
Komatsu : 4d95s-W-1g-T(S/N 23318-Up (For Trimming Dozer)) : Cylinder Block : Oil Pan
| 01***16 | Bolt, Mount Solenoid Valve | 22 |
| 01***16 | Screw | 22 |
| 01***30 | Bolt,(Water Separator Spec.) | 2 |
Komatsu : 4d95s-W-1g-T(S/N 23318-Up (For Trimming Dozer)) : Cylinder Block : Piston And Connecting Rod
| 04***12 | Ring, Snap | 8 |
| 62***40 | Piston (S) | 4 |
| 62***00 | Piston Ring Ass'Y,Per Cylinder | 4 |
Cylinder Head
Komatsu : 4d95s-W-1g-T(S/N 23318-Up (For Trimming Dozer)) : Cylinder Head : Air Cleaner And Mounting
| 01***30 | Bolt,(Water Separator Spec.) | 1 |
| 01***16 | Bolt,(With Alternator Cover Type) | 2 |
| 01***06 | Nut | 1 |
Komatsu : 4d95s-W-1g-T(S/N 23318-Up (For Trimming Dozer)) : Cylinder Head : Air Intake Manifold And Connection(#23318-30907)
| 01***65 | Stud | 1 |
| 01***65 | Bolt,(With Water Separator) | 3 |
| 01***75 | Bolt,(For Shipping) | 8 |
Komatsu : 4d95s-W-1g-T(S/N 23318-Up (For Trimming Dozer)) : Cylinder Head : Air Intake Manifold And Connection(#30908-)
| 01***65 | Stud | 1 |
| 01***12 | Bolt,(With Speedometer) | 4 |
| 01***65 | Bolt,(With Water Separator) | 3 |
Komatsu : 4d95s-W-1g-T(S/N 23318-Up (For Trimming Dozer)) : Cylinder Head : Cylinder Head
| 01***20 | Bolt, Hose Clamps (Inlet And Return Line Hoses) | 4 |
| 01***32 | Washer,(Not Used With Emergency Str.) | 17 |
| 02***04 | Plug, Pipe | 1 |
Komatsu : 4d95s-W-1g-T(S/N 23318-Up (For Trimming Dozer)) : Cylinder Head : Cylinder Head Cover
| 61***10 | Cap, Oil Filler | 1 |
| 61***20 | Screw | 3 |
| 61***30 | Washer,(B) | 3 |
Komatsu : 4d95s-W-1g-T(S/N 23318-Up (For Trimming Dozer)) : Cylinder Head : Exhaust Manifold And Muffler
| 01***25 | Grub Screw | 4 |
| 01***45 | Bolt, Bracket Mounting | 8 |
| 61***80 | Gasket,Exhaust Manifold | 1 |
Komatsu : 4d95s-W-1g-T(S/N 23318-Up (For Trimming Dozer)) : Cylinder Head : Rocker Arm
| 01***12 | Bolt,(Without R.P.C.U.) | 1 |
| 01***65 | Bolt,(For Alternator Bracket Mount) | 5 |
| 61***30 | Nut | 8 |
Electrical System
Komatsu : 4d95s-W-1g-T(S/N 23318-Up (For Trimming Dozer)) : Electrical System : Alternator (13a)
| 60***80 | Alternator A. (13a) | 1 |
| KD***31 | Bushing,Insulator | 2 |
| KD***80 | Packing | 1 |
Komatsu : 4d95s-W-1g-T(S/N 23318-Up (For Trimming Dozer)) : Electrical System : Alternator And Mounting (13a)
| 01***35 | Bolt,(Cold Weather Spec.) | 1 |
| 01***55 | Screw | 1 |
| 01***11 | Nut,(For Center Guard) | 1 |
Komatsu : 4d95s-W-1g-T(S/N 23318-Up (For Trimming Dozer)) : Electrical System : Starting Motor (2.8kw)
| 60***40 | Starting Motor Ass'Y,(2.8kw) | 1 |
| KD***61 | Bracket,Center | 1 |
| KD***61 | Brush Holder A | 1 |
Komatsu : 4d95s-W-1g-T(S/N 23318-Up (For Trimming Dozer)) : Electrical System : Starting Motor And Mounting (2.8kw)
| 01***30 | Bolt | 2 |
| 07***95 | O-Ring,Transmission Strainer | 1 |
| (6***0) | Starting Motor Ass'Y,(2.8kw) (See Fig.A6210-B0b3) | 1 |
Engine Kit
Komatsu : 4d95s-W-1g-T(S/N 23318-Up (For Trimming Dozer)) : Engine Kit : Gasket Kit
| 01***12 | Washer,Lock (Noise Suppression Spec.) (K2) | 1 |
| 07***65 | O-Ring,Injection Pump Case | 1 |
| 07***85 | O-Ring,(Without Fuel Level Gauge) | 1 |
Fuel System
Komatsu : 4d95s-W-1g-T(S/N 23318-Up (For Trimming Dozer)) : Fuel System : Fuel Filter And Piping
| 01***65 | Bolt,(With Water Separator) | 2 |
| 07***12 | Gasket,Mechanical Pump Piping | 1 |
| 07***12 | Gasket,(Without Air Compressor Type) (K1) | 4 |
Komatsu : 4d95s-W-1g-T(S/N 23318-Up (For Trimming Dozer)) : Fuel System : Fuel Filter And Piping (For Large Capacity)(#56149-)
| 01***65 | Bolt,(With Water Separator) | 2 |
| 07***12 | Gasket,Mechanical Pump Piping | 1 |
| 07***12 | Gasket,(Without Air Compressor Type) (K1) | 4 |
Komatsu : 4d95s-W-1g-T(S/N 23318-Up (For Trimming Dozer)) : Fuel System : Fuel Injection Pump (Feed Pump)
| DK***20 | Bolt, Joint | 1 |
| DK***00 | Valve,Check | 2 |
| DK***20 | Pump,Priming | 1 |
Komatsu : 4d95s-W-1g-T(S/N 23318-Up (For Trimming Dozer)) : Fuel System : Fuel Injection Pump (Governor) (1/2)
| DK***00 | Shim? 2.00mm,(High Altitude Spec.) | 0 |
| DK***00 | Adapter | 1 |
| DK***80 | Nut | 1 |
Komatsu : 4d95s-W-1g-T(S/N 23318-Up (For Trimming Dozer)) : Fuel System : Fuel Injection Pump (Governor) (2/2)
| DK***20 | Lever | 1 |
| DK***40 | Gasket,Air Compressor | 2 |
| DK***20 | Capsule,Spring | 1 |
Komatsu : 4d95s-W-1g-T(S/N 23318-Up (For Trimming Dozer)) : Fuel System : Fuel Injection Pump (Pump) (1/2)
| 62***30 | Injection Pump Ass'Y | 1 |
| 62***31 | Injection Pump Ass'Y | 1 |
| DK***30 | Bearing | 0 |
Komatsu : 4d95s-W-1g-T(S/N 23318-Up (For Trimming Dozer)) : Fuel System : Fuel Injection Pump (Pump) (2/2)
| DK***40 | Shim? 0.50mm, Shim, 0.50mm; Was Dk029311-0040 | 0 |
| DK***90 | Shim? 0.25mm, Shim, 0.25mm; Was Dk029311-0590 | 0 |
| DK***00 | Sleeve,Control | 4 |
Komatsu : 4d95s-W-1g-T(S/N 23318-Up (For Trimming Dozer)) : Fuel System : Fuel Injection Pump And Piping
| 01***35 | Stud | 4 |
| 01***12 | Bolt | 2 |
| 01***25 | Screw | 2 |
Komatsu : 4d95s-W-1g-T(S/N 23318-Up (For Trimming Dozer)) : Fuel System : Fuel Nozzle And Spill Pipe
| 07***50 | Tube,Spill | 1 |
| 07***55 | Tube,Spill | 1 |
| 07***85 | Clip | 2 |
Komatsu : 4d95s-W-1g-T(S/N 23318-Up (For Trimming Dozer)) : Fuel System : Water Separator And Piping(#43240-)
| 01***80 | Stud | 2 |
| 01***25 | Bolt,(With Corrosion Resistor) | 2 |
| 01***08 | Nut,See Fig. K4010-04a0 | 2 |
Lubricating Oil System
Komatsu : 4d95s-W-1g-T(S/N 23318-Up (For Trimming Dozer)) : Lubricating Oil System : Lubricating Oil Cooler
| 01***25 | Bolt,(With Corrosion Resistor) | 4 |
| 01***30 | Bolt,(Water Separator Spec.) | 7 |
| 01***50 | Bolt,(With Corrosion Resistor) | 1 |
Komatsu : 4d95s-W-1g-T(S/N 23318-Up (For Trimming Dozer)) : Lubricating Oil System : Lubricating Oil Filter
| 01***25 | Bolt,(With Corrosion Resistor) | 4 |
| 07***12 | Washer, Gasket,(Without Thermo Sensor) (K1) | 1 |
| 60***40 | Cartridge,Engine Oil Filter (D31s) | 1 |
Komatsu : 4d95s-W-1g-T(S/N 23318-Up (For Trimming Dozer)) : Lubricating Oil System : Lubricating Oil Pump And Suction Pipe
| 01***12 | Bolt,(See Fig.0501) | 1 |
| 01***16 | Screw | 6 |
| 01***55 | Bolt,(With Engine Stop Motor Type) | 1 |
4D95S-W-1G-T(S/N 23318-UP (FOR TRIMMING DOZER)) serial number reference
The engine serial plate is located on the left side of the engine block or on a metal plate affixed near the valve cover. Read the full engine model code and serial number stamped on the plate.
| Prefix | Identifies | Notes |
|---|---|---|
| 4D95S-W-1G-T | Trimming Dozer | S/N 23318-UP. Confirmed by factory parts catalog and dealer serial guides for this specific engine variant. |
Frequently asked questions
What is the engine type for the Komatsu 4D95S-W-1G-T?
The Komatsu 4D95S-W-1G-T is a 4-cylinder, water-cooled, turbocharged diesel engine. It is part of the 95 Series engine family, designed for mid-size dozers like the GD85A and GD105A. The 'W' indicates water cooling, and 'T' indicates turbocharging. It typically produces around 85-105 horsepower depending on the specific dozer application and tuning.
What is the operating weight range for machines using this engine?
Operating weight varies by configuration and series. For the GD85A and GD105A trimming dozers equipped with the 4D95S-W-1G-T engine, operating weights typically range from 9,000 kg to 12,000 kg (19,840 lb to 26,455 lb). Specific weight depends on the undercarriage type (standard vs. LGP), blade size, and counterweight configuration.
What engine replaced the 4D95S-W-1G-T?
The 4D95S-W-1G-T was succeeded by newer Komatsu engine families such as the SAA6D95LE and SAA6D107E series, which meet higher emissions tiers (Tier 4 Final/Stage V). These newer engines incorporate common rail fuel injection and aftertreatment systems like DPF and SCR, replacing the mechanical injection and simpler turbocharging of the 4D95S series.
What 4D95S-W-1G-T(S/N 23318-UP (FOR TRIMMING DOZER)) owners discuss
What are the typical powertrain and hydraulic behaviors associated with the Komatsu 4D95S-W-1G-T engine in trimming dozers?
What undercarriage or wear patterns are typical for machines powered by this engine series?
What are the known engine quirks for the 4D95S series, particularly regarding rebuilds?
What are common electrical or sensor issues reported for this engine?
What should be checked when buying a used Komatsu 4D95S-W-1G-T (S/N 23318-UP) for trimming dozer?
What fluids are recommended for the Komatsu 4D95S-W-1G-T engine and related systems?
What is a safety-critical fix related to the fuel system on this engine?
Compiled from owner and technician discussions across the industry — experiences vary by serial range and machine history.
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