Komatsu S4D105-2D(S/N 22068-UP)
Maintenance schedule, common problems & OEM parts breakdown
The Komatsu S4D105-2D is a four-cylinder, turbocharged diesel engine belonging to the 105 Series, specifically engineered for mid-size construction machinery. It powers equipment such as the D40 and D45 series crawler dozers, as well as various excavator and grader models. This engine configuration is typically found in machines with operating weights ranging from approximately 12,000 to 20,000 lbs (5,400 to 9,100 kg). Production for this specific engine variant spans several decades, serving as a workhorse for Komatsu's mid-tier fleet before being succeeded by newer emission-compliant generations. It was offered in various configurations to meet regional standards and machine-specific torque requirements.
Across the 105 Series lineage, the S4D105-2D represents a transitional generation between older naturally aspirated or early turbo models and modern Tier 4/Stage V compliant engines. While later variants like the S4D105-3 introduced updated fuel systems and emissions controls, the S4D105-2D remains highly relevant in the used and parts market due to its mechanical simplicity and widespread installation in existing fleets. Its enduring presence ensures a robust supply of aftermarket components and a deep knowledge base for technicians, making it a cost-effective powerplant for older dozers and excavators still in active service.
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 S4D105-2D(S/N 22068-UP) specifications
Engine
| Model | S4D105-2D |
| Series/Generation | S4D105 Series |
| Cylinders | 4 |
| Displacement | 4.33 L (264.2 cu in) |
| Bore x Stroke | 105 mm x 125 mm (4.13 in x 4.92 in) |
| Aspiration | Turbocharged |
| Emissions Tier | Not documented for this exact serial range — verify with your dealer |
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 |
| Engine Dry Weight | 540 kg (1,190 lb) |
Dimensions
| Engine Length (Fan to flywheel housing) | 986 mm (38.8 in) |
| Engine Width | 776 mm (30.6 in) |
| Engine Height (Muffler to oil pan) | 1,375 mm (54.1 in) |
Performance
| Gross Power | 90 HP (67 kW) @ 2,400 rpm |
| Net Power | 90 HP (67 kW) @ 2,400 rpm |
| Maximum Torque | 32 kgm (235 N·m) @ 1,400 rpm |
| High Idle Speed | 2,600 - 2,700 rpm |
| Low Idle Speed | 730 - 780 rpm |
| 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 |
Service capacities (summary)
| Engine Oil Capacity | 18 L (4.76 gal) |
| Cooling System Capacity | 40 L (10.56 gal) |
| Fuel Tank Capacity | Not documented for this exact serial range — verify with your dealer |
| Hydraulic System Capacity | 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.
S4D105-2D(S/N 22068-UP) fluids & capacities
| System | Capacity | Recommended fluid |
|---|---|---|
| Engine Crankcase (with filter) | 13 L (3.4 US gal) | Komatsu Diesel Engine Oil (Viscosity varies by climate; refer to factory spec sheet for SAE grade selection) |
| Cooling System | 22 L (5.8 US gal) | Komatsu Super Coolant AF-NAC |
| Fuel Tank | Not documented for this exact serial range — verify with your dealer | ASTM D975 No.1 and No.2 |
| Transmission/Powertrain | Not documented for this exact serial range — verify with your dealer | Komatsu Powertrain Oil TO10 or TO30 (Viscosity varies by climate) |
| Final Drives (each) | Not documented for this exact serial range — verify with your dealer | Komatsu Axle Oil AXO80 |
| Hydraulic System and Tank | Not documented for this exact serial range — verify with your dealer | Komatsu Hydraulic Oil HO56 |
| Axles/Differentials | Not documented for this exact serial range — verify with your dealer | Komatsu Axle Oil AXO80 |
| Grease | N/A | Not specified in source text |
Capacities are refill values from factory literature — always fill to the dipstick/sight gauge, not the number.
Komatsu S4D105-2D(S/N 22068-UP) maintenance schedule
| Service interval | Tasks |
|---|---|
| Every 10 h |
|
| Every 250 h |
|
| Every 500 h |
|
| Every 1,000 h |
|
| Every 2,000 h |
|
Servicing the S4D105-2D(S/N 22068-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) or sodium (coolant). Check hydraulic fluid for ISO cleanliness and water content. Test coolant SCA concentration to prevent liner cavitation. Monitor DEF levels daily on Tier 4 variants. Early detection of fuel dilution or soot buildup in the engine oil prevents premature bearing wear and turbocharger damage specific to the S4D105-2D's lubrication circuit.
Corrective & Common Repairs
Address intermittent starting or shutdowns by inspecting the Electronic Control Module (ECM) power supply and sensor wiring, particularly the intake air temperature and coolant temperature sensors. Replace worn fuel injection nozzles if power loss or excessive smoke occurs. Check the thermostart system for proper fuel supply during cold starts. Inspect the T04B turbocharger shaft play and bearing condition if boost pressure drops. Repair hydraulic hose leaks promptly to maintain pump pressure and prevent contamination of the S4D105-2D's sensitive valve train.
Overhaul & Rebuild Points
Plan for inframe overhaul when cylinder compression drops below specification or oil consumption exceeds limits. Replace piston rings, liners, and bearings as a set. Inspect the cylinder head for warpage and valve seat wear. Check the crankshaft for journal wear and replace if out of tolerance. Rebuild the fuel injection pump and governor assembly if timing drifts or pressure leaks occur. Ensure the turbocharger is replaced or rebuilt simultaneously to maintain proper exhaust flow and boost pressure for the S4D105-2D's performance.
Seasonal & Environment Servicing
In cold climates, verify the thermostart system functions correctly for easy starting. Use low-viscosity Komatsu diesel engine oil (e.g., SAE 5W-30) for winter operations. In dusty environments, inspect the pre-cleaner and air filter daily; clean or replace the outer element more frequently if the restriction indicator triggers. In hot conditions, ensure the radiator and oil cooler fins are free of debris to prevent overheating. Check coolant glycol concentration before winter to prevent freezing. Inspect all belts and hoses for heat degradation in high-temperature applications.
S4D105-2D(S/N 22068-UP) common service parts
| Part number | Part | Notes | |
|---|---|---|---|
| 6130-71-6102 | Fuel Filter Ass'Y | Fuel system service | Check fitment → |
| 07000-02075 | O-Ring,Steering Oil Filter | Lubrication service | Check fitment → |
| 600-181-8210 | Element,Outer | Scheduled service item | Check fitment → |
| 600-181-8310 | Element,Inner | Scheduled service item | Check fitment → |
| 6131-81-7030 | Element Ass'Y | Scheduled service item | Check fitment → |
Always confirm against your machine's serial number — cross-check any part in Heavy Parts AI before ordering.
S4D105-2D(S/N 22068-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 pin connector | 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 |
| 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 circuit or airflow restriction | Check for a sensor short or an airflow restriction |
| CA441 | Battery voltage too low | Weak battery or failing alternator | Replace the alternator or battery; check the voltage regulator |
| CA442 | Battery voltage too high | Alternator overcharging or voltage regulator failure | Replace the alternator or battery; check the voltage regulator |
| 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 |
| B@BCNS | Engine coolant overheating | Low coolant level, blocked radiator fins, or fan belt failure | Check 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.
S4D105-2D(S/N 22068-UP) attachments & work tools
Bulldozer Blade Systems
The S4D105-2D engine (S/N 22068-UP) is installed in the D40A-1, D40AF-1A, D40PF-1A, D40PL-1, D45A-1, and D45P-1 dozer series. These machines utilize standard straight or angle dozer blades appropriate for the 10-15 ton class. Factory configurations include standard guard bars and ripper mounting points on the rear frame for secondary earthmoving tasks.
Excavator Quick Couplers
This engine powers the PC100-1, PC100-2, PC120-1, PC120-2, PC150-1, PC200-1, PC200-2, PC200-3, PC220-3, PC220-1, and PC220-2 excavator families. These models are equipped with factory-approved hydraulic quick coupler systems for rapid tool changes. The hydraulic arrangement supports standard flow rates required for mechanical or hydraulic attachments.
Grader Blade Configurations
The S4D105-2D engine is used in the GD200A-1, GD300A-1, GD405A-1, GD500R-2A, GD505A-2, GD521A-1, GD523A-1, GD525A-1, and GD611A-1 motor grader series. These units feature multi-way blades with moldboard extensions and angle capabilities. Guarding options include side cutters and wing extensions for fine grading and ditching operations.
Wheeled Loader Buckets
Compatible with the WA series wheel loaders powered by this engine class. Standard bucket sizes vary by specific loader model but are designed for general earthmoving and material handling. Optional buckets include rock, coal, and light material variants, all utilizing the standard loader pin-on or quick-attach mounting interface.
All S4D105-2D(S/N 22068-UP) assemblies by section
Every catalogued assembly group for the Komatsu S4D105-2D(S/N 22068-UP). Open an assembly to preview the parts inside — full OEM part numbers are available in Heavy Parts AI.
Cooling And Electrical Systems
Komatsu : S4d105-2d(S/N 22068-Up) : Cooling And Electrical Systems : Alternator
| 60***50 | Alternator A. (13a),(With Non Hardening Pulley) | 1 |
| KD***30 | Holder,Brush | 1 |
| KD***80 | Packing | 1 |
Komatsu : S4d105-2d(S/N 22068-Up) : Cooling And Electrical Systems : Alternator And Mounting
| 01***25 | Bolt,(Sandy? Dusty Terrain Spec.) | 1 |
| 01***55 | Bolt,(For Suction? Reversible Fan) | 1 |
| 01***25 | Bolt - Rear Guard Mounting | 2 |
Komatsu : S4d105-2d(S/N 22068-Up) : Cooling And Electrical Systems : Safety Relay And Resistor
| 60***30 | Resistor | 1 |
| 60***10 | Alternator A | 1 |
| 61***50 | Resistor | 1 |
Komatsu : S4d105-2d(S/N 22068-Up) : Cooling And Electrical Systems : Starting Motor
| 60***71 | Starting Motor A | 1 |
| KD***10 | Clutch Ass'Y,Over Running | 1 |
| KD***80 | Shift Lever Ass'Y | 1 |
Komatsu : S4d105-2d(S/N 22068-Up) : Cooling And Electrical Systems : Starting Motor And Mounting
| 01***35 | Bolt - Torque Converter Totransmission Mounting | 3 |
| 01***36 | Washer,Radio Controlled Slag Handling | 3 |
| 61***20 | O-Ring (K2) | 1 |
Komatsu : S4d105-2d(S/N 22068-Up) : Cooling And Electrical Systems : Water Pump And Cooling Fan
| 01***20 | Bolt,(Sandy? Dusty Terrain Spec.) | 2 |
| 01***25 | Bolt,(Without Auto Priming System) | 8 |
| 01***25 | Bolt,(Sandy? Dusty Terrain Spec.) | 6 |
Cylinder Block
Komatsu : S4d105-2d(S/N 22068-Up) : Cylinder Block : Balancer Shaft
| 01***20 | Bolt,(Sandy? Dusty Terrain Spec.) | 4 |
| 01***25 | Washer,Spring?(Sandy And Dusty Spec.) | 4 |
| 04***19 | Key,(Dk025805-1910) | 1 |
Komatsu : S4d105-2d(S/N 22068-Up) : Cylinder Block : Camshaft And Tappet
| 01***20 | Bolt,(Sandy? Dusty Terrain Spec.) | 2 |
| 01***25 | Bolt,(Sandy? Dusty Terrain Spec.) | 1 |
| 01***25 | Washer,Spring?(Sandy And Dusty Spec.) | 2 |
Komatsu : S4d105-2d(S/N 22068-Up) : Cylinder Block : Crankshaft And Timing Gear
| 01***30 | Bolt,(For France Noise Suppression) | 4 |
| 02***04 | Plug,(Not Shown) | 4 |
| 04***25 | Key | 1 |
Komatsu : S4d105-2d(S/N 22068-Up) : Cylinder Block : Cylinder Block
| 01***55 | Bolt,(For Suction? Reversible Fan) | 4 |
| 01***65 | Bolt | 3 |
| 04***14 | Pin, Dowel | 2 |
Komatsu : S4d105-2d(S/N 22068-Up) : Cylinder Block : Flywheel And Flywheel Housing
| 01***14 | Bolt | 3 |
| 01***25 | Bolt,(Sandy? Dusty Terrain Spec.) | 17 |
| 01***40 | Bolt,(Dust And Dirt Protection) | 5 |
Komatsu : S4d105-2d(S/N 22068-Up) : Cylinder Block : Front Cover And Support
| 01***12 | Bolt,(Without R.P.C.U.) | 2 |
| 01***22 | Bolt | 2 |
| 01***45 | Bolt,(For Suction? Reversible Fan) | 10 |
Komatsu : S4d105-2d(S/N 22068-Up) : Cylinder Block : Oil Pan
| 01***16 | Bolt,(For Slag Handling) | 2 |
| 01***18 | Bolt | 2 |
| 01***20 | Bolt,(Sandy? Dusty Terrain Spec.) | 2 |
Komatsu : S4d105-2d(S/N 22068-Up) : Cylinder Block : Piston And Connecting Rod
| 61***15 | Bolt,(Service Parts) | 2 |
| 61***22 | Nut,(Service Parts) | 2 |
| 61***30 | Washer,(Service Parts) | 2 |
Cylinder Head
Komatsu : S4d105-2d(S/N 22068-Up) : Cylinder Head : Air Intake Connection And Air Cleaner
| 01***22 | Bolt,(Cold Terrain Spec.) | 4 |
| 01***25 | Bolt,(Without Auto Priming System) | 4 |
| 01***06 | Nut, Regular Hexagon (M8-1.25) | 6 |
Komatsu : S4d105-2d(S/N 22068-Up) : Cylinder Head : Compression Release
| 01***25 | Bolt,(Without Auto Priming System) | 1 |
| 01***25 | Bolt - Rear Guard Mounting | 1 |
| 01***05 | Nut (Welded) | 1 |
Komatsu : S4d105-2d(S/N 22068-Up) : Cylinder Head : Cylinder Head
| 01***16 | Bolt,(For Slag Handling) | 6 |
| 01***35 | Stud | 8 |
| 01***25 | Washer,Spring?(Sandy And Dusty Spec.) | 6 |
Komatsu : S4d105-2d(S/N 22068-Up) : Cylinder Head : Cylinder Head Cover
| 01***22 | Bolt,(Cold Terrain Spec.) | 10 |
| 01***20 | Bolt,(Large Capacity Type) (Std) | 1 |
| 01***25 | Bolt,(Sandy? Dusty Terrain Spec.) | 2 |
Komatsu : S4d105-2d(S/N 22068-Up) : Cylinder Head : Exhaust Manifold And Muffler
| 01***35 | Stud | 1 |
| 01***11 | Nut (M14-1.50 Thd), Nut; Was 01582-01411 | 2 |
| 01***25 | Washer,Spring?(Sandy And Dusty Spec.) | 2 |
Komatsu : S4d105-2d(S/N 22068-Up) : Cylinder Head : Rocker Arm And Housing
| 01***12 | Bolt,(Without R.P.C.U.) | 1 |
| 01***20 | Bolt,(Sandy? Dusty Terrain Spec.) | 4 |
| 01***85 | Bolt | 15 |
Komatsu : S4d105-2d(S/N 22068-Up) : Cylinder Head : Turbocharger (Except Japan)
| 61***01 | Turbocharger Ass'Y,(See Fig.141) | 1 |
| 61***02 | Turbocharger Ass'Y,(See Fig.141) | 1 |
| 61***03 | Turbocharger Ass'Y,(See Fig.141) | 1 |
Komatsu : S4d105-2d(S/N 22068-Up) : Cylinder Head : Water Pipe And Thermostat
| 01***18 | Bolt | 3 |
| 01***22 | Bolt,(Cold Terrain Spec.) | 6 |
| 01***35 | Bolt,(Without Auto Priming System) | 3 |
Fuel System
Komatsu : S4d105-2d(S/N 22068-Up) : Fuel System : Fuel Filter And Mounting
| 01***35 | Bolt, Mounting - Flywheel Housing End | 2 |
| 01***30 | Washer,Spring(Sandy?Dusty Terrain S.) | 2 |
| 07***12 | Gasket,Mechanical Pump Piping | 1 |
Komatsu : S4d105-2d(S/N 22068-Up) : Fuel System : Fuel Injection Pump (Feed Pump)
| 61***10 | Injection Pump A.,(See Fig.451) | 1 |
| 61***11 | Injection Pump A | 1 |
| DK***20 | Housing | 1 |
Komatsu : S4d105-2d(S/N 22068-Up) : Fuel System : Fuel Injection Pump (Governor)
| 61***10 | Injection Pump A.,(See Fig.451) | 1 |
| DK***00 | Adapter | 1 |
| DK***20 | Capsule,Spring | 1 |
Komatsu : S4d105-2d(S/N 22068-Up) : Fuel System : Fuel Injection Pump (Pump)
| 61***10 | Injection Pump A.,(See Fig.451) | 1 |
| 61***11 | Injection Pump A | 1 |
| DK***00 | Shim? 0.85mm | 0 |
Komatsu : S4d105-2d(S/N 22068-Up) : Fuel System : Fuel Injection Pump And Piping
| 01***16 | Bolt (Welded) | 1 |
| 01***18 | Bolt | 2 |
| 01***20 | Bolt,(Sandy? Dusty Terrain Spec.) | 10 |
Komatsu : S4d105-2d(S/N 22068-Up) : Fuel System : Fuel Nozzle And Spill Pipe
| 01***65 | Bolt | 8 |
| 07***12 | Gasket,Mechanical Pump Piping | 6 |
| 07***37 | Clamp, Overflow Hose | 2 |
Komatsu : S4d105-2d(S/N 22068-Up) : Fuel System : Thermostat And Piping(#22068-25369)
| 01***12 | Bolt (M8-1.25x12) | 3 |
| 01***22 | Bolt,(Cold Terrain Spec.) | 3 |
| 01***25 | Washer,Spring?(Sandy And Dusty Spec.) | 6 |
Komatsu : S4d105-2d(S/N 22068-Up) : Fuel System : Thermostat And Piping(#25370-)
| 01***25 | Bolt,(Without Auto Priming System) | 2 |
| 01***05 | Nut (Welded) | 2 |
| 01***19 | Washer,(Not Used With Ventilator) | 2 |
Lubricating Oil System
Komatsu : S4d105-2d(S/N 22068-Up) : Lubricating Oil System : Lubricating Oil Cooler
| 01***35 | Bolt, Mounting - Flywheel Housing End | 8 |
| 01***08 | Nut,R.H. Thread | 4 |
| 01***30 | Washer,Spring(Sandy?Dusty Terrain S.) | 12 |
Komatsu : S4d105-2d(S/N 22068-Up) : Lubricating Oil System : Lubricating Oil Filter
Komatsu : S4d105-2d(S/N 22068-Up) : Lubricating Oil System : Lubricating Oil Pump
| 01***16 | Bolt,(For Slag Handling) | 2 |
| 01***20 | Bolt,(Sandy? Dusty Terrain Spec.) | 1 |
| 01***25 | Bolt,(Without Auto Priming System) | 2 |
Komatsu : S4d105-2d(S/N 22068-Up) : Lubricating Oil System : Lubricating Oil Strainer
| 01***22 | Bolt | 2 |
| 01***25 | Bolt,(Sandy? Dusty Terrain Spec.) | 2 |
| 01***55 | Bolt,(For Suction? Reversible Fan) | 3 |
Komatsu : S4d105-2d(S/N 22068-Up) : Lubricating Oil System : Turbocharger Lubricating Oil Piping
| 01***22 | Bolt,(Cold Terrain Spec.) | 2 |
| 01***25 | Washer,Spring?(Sandy And Dusty Spec.) | 4 |
| 01***29 | Washer,Spring (Cold Weather Spec.) | 2 |
Tool And Kit
Komatsu : S4d105-2d(S/N 22068-Up) : Tool And Kit : Gasket Kit
| 01***12 | Washer,Lock (K2) | 1 |
| 01***08 | Washer,Lock (Kit) | 1 |
| 01***16 | Washer,Lock (K2) | 1 |
S4D105-2D(S/N 22068-UP) serial number reference
The PIN plate for the Komatsu S4D105-2D engine is typically located on the engine block, often on the left side near the injection pump or on a metal data plate affixed to the valve cover area. The prefix 'S4D105-2D' is read directly from this engine data plate, not the machine chassis serial plate, to identify the specific engine variant fitted to the equipment.
| Prefix | Identifies | Notes |
|---|---|---|
| S4D105-2D | Engine Model | Engine model designation for the S/N 22068-UP range. The source text explicitly lists 'S4D105-2D S/N 22068-UP' as the machine identifier in parts catalog listings. The 'S' prefix indicates a turbocharged engine with an aftercooler. The '4' indicates a 4-cylinder inline configuration. The '105' indicates the bore/size series. The '-2D' indicates the specific generation/revision of the engine model. |
Frequently asked questions
What engine does the Komatsu S4D105-2D use?
The Komatsu S4D105-2D is a four-cylinder, turbocharged diesel engine from the 105 Series. It is mechanically distinct from the S4D102E variants and is used in specific mid-size dozers and excavators.
What is the operating weight of machines powered by this engine?
Machines equipped with the S4D105-2D engine, such as the D40 and D45 series dozers, typically have operating weights ranging from approximately 12,000 to 20,000 lbs (5,400 to 9,100 kg), varying by configuration and attachment.
What replaced the S4D105-2D engine?
The S4D105-2D was succeeded by newer generations of the 105 Series, such as the S4D105-3 and later Tier 4/Stage V compliant engines, which feature updated fuel injection systems and emissions control technologies.
What S4D105-2D(S/N 22068-UP) owners discuss
What are the known powertrain and hydraulic behaviors for the Komatsu S4D105-2D engine series?
What undercarriage or wear patterns are typical for machines equipped with this engine type?
What are the specific engine quirks for the S4D105-2D series compared to earlier generations?
What are the common electrical and sensor issues reported for this machine type?
What should be checked when buying a used machine with the S4D105-2D engine?
What are the recommended fluid specifications for this engine series?
What is a safety-critical fix associated with the S4D105-2D engine that requires dealer verification?
Compiled from owner and technician discussions across the industry — experiences vary by serial range and machine history.
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