Komatsu S4D105-1C(S/N 19078-UP)
Maintenance schedule, common problems & OEM parts breakdown
The Komatsu S4D105-1C engine (S/N 19078-UP) is a four-cylinder diesel powerplant belonging to the 105 Series family, primarily utilized in the D45A-1, D45P-1, and D45S-1 crawler dozer configurations. These machines represent the mid-size heavy dozer class, operating in a weight range that supports significant earthmoving and site development tasks. The S4D105-1C succeeded earlier 105 Series iterations and was later replaced by the S4D105-3C (S/N 44579-UP) as Komatsu updated its emissions and performance standards. Configurations for these dozers typically included standard, low-ground-pressure (LGP), and specialized variants designed for varying soil conditions and operational demands.
Across the 105 Series generations, Komatsu refined fuel injection precision, turbocharging efficiency, and emissions compliance, transitioning from the S4D105-1C to the S4D105-2C and eventually the S4D105-3C. The S4D105-1C remains relevant in the used and parts market due to the widespread deployment of the D45 series in heavy construction and mining applications. Its robust design and availability of aftermarket support make it a critical reference for fleet managers maintaining older dozer fleets, ensuring continued operational viability through targeted component replacement and scheduled maintenance.
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 S4D105-1C(S/N 19078-UP) specifications
Engine
| Model | S4D105-1C |
| Series | 105 Series |
| Displacement | 4.3 l (264 cu. inch) |
| Cylinders | 4 |
| 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 |
| 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 |
Service capacities (summary)
| Engine oil capacity | 13 l (varies by machine series) |
| Cooling system capacity | 22 l (varies by machine series) |
| 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.
S4D105-1C(S/N 19078-UP) fluids & capacities
| System | Capacity | Recommended fluid |
|---|---|---|
| Engine Crankcase (with filter) | 13 L (3.4 US gal) | Komatsu Diesel Engine Oil (API CD or higher); SAE 15W-40 recommended for general use; SAE 5W-30 for cold climates |
| Cooling System | 22 L (5.8 US gal) | Komatsu Super Coolant AF-NAC (JIS K 2234-1987 / ASTM 3306) |
| Fuel Tank | Not documented for this exact serial range — verify with your dealer | ASTM D975 No.1 and No.2 fuel |
| Transmission/Powertrain | Not documented for this exact serial range — verify with your dealer | Komatsu Powertrain Oil TO10 (SAE 10W) or TO30 (SAE 30W) |
| Final Drives | Not documented for this exact serial range — verify with your dealer | Komatsu Axle Oil AXO80 (SAE 80W, API GL-4) |
| Hydraulic System and Tank | Not documented for this exact serial range — verify with your dealer | Komatsu Hydraulic Oil HO (ISO VG46) |
| Axles/Differentials | Not documented for this exact serial range — verify with your dealer | Komatsu Axle Oil AXO80 (SAE 80W, API GL-4) |
| Grease | Not applicable | General purpose lithium-based grease meeting Komatsu engineering standards |
Capacities are refill values from factory literature — always fill to the dipstick/sight gauge, not the number.
Komatsu S4D105-1C(S/N 19078-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 S4D105-1C(S/N 19078-UP) beyond the schedule
Predictive Maintenance & Fluid Analysis
Utilize Komatsu Oil/Wear Analysis (KOWA) at every 500-hour interval to monitor engine oil and hydraulic fluid conditions. Track wear metals such as iron, copper, and lead in the engine oil to detect internal component degradation early. Analyze hydraulic fluid for particle count and water content to prevent pump and valve damage. Monitor coolant pH and SCA concentration to ensure corrosion protection within the S4D105-1C cooling system. Early detection of fuel dilution or coolant contamination in the oil allows for timely intervention before catastrophic engine failure occurs.
Corrective & Common Repairs
Address common S4D105-1C issues by inspecting the fuel system for leaks and injector wear, which often cause power loss and excessive smoke. Check the turbocharger for shaft play and seal integrity, as boost pressure loss is a frequent failure point. Inspect the hydraulic return filter for blockage, which can lead to overheating and seal damage in the main hydraulic pump. Replace worn belts and hoses during the 2000-hour service to prevent sudden breakdowns. Verify the condition of the engine data plate and sensor connections to ensure accurate ECM monitoring and fault code generation.
Overhaul & Rebuild Points
Plan for inframe overhaul of the S4D105-1C when compression tests reveal significant cylinder leakage or when oil consumption exceeds normal limits. Key rebuild components include piston rings, cylinder liners, and valve guides. Inspect the crankshaft and connecting rod bearings for wear during major service intervals. Replace the turbocharger if shaft clearance exceeds specifications or if compressor blades show damage. Ensure the engine block and cylinder head are inspected for cracks or warping before reassembly to maintain proper sealing and performance.
Seasonal & Environment Servicing
In cold climates, verify the coolant freeze protection level and use the correct viscosity engine oil to ensure reliable starting. In dusty environments, inspect the air filter restriction indicator more frequently and clean the radiator and oil cooler fins to prevent overheating. Check the fuel water separator daily to remove accumulated water that can damage the injection system. Inspect undercarriage components for mud buildup and track tension for proper alignment. Adjust hydraulic system pressures and flows to account for temperature-induced viscosity changes in the fluid.
S4D105-1C(S/N 19078-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 → |
| 6130-51-5103 | Oil Filter Ass'Y | Lubrication service | Check fitment → |
| 600-181-8210 | Element,Outer | Scheduled service item | Check fitment → |
| 600-181-8310 | Element,Inner | Scheduled service item | Check fitment → |
Always confirm against your machine's serial number — cross-check any part in Heavy Parts AI before ordering.
S4D105-1C(S/N 19078-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 | Inspect the sensor wiring and connector for damage or corrosion; replace the speed sensor if voltage is absent at the pin |
| CA111 | Internal engine controller (ECM) fault | Electronic Control Module internal failure or software corruption | Replace or reprogram the ECM; verify power and ground connections first |
| CA451 | Common rail pressure sensor feedback value too high | Malfunctioning rail pressure sensor, actual overpressure condition, or sensor wiring short | Diagnose the fuel rail pressure sensor circuit and check for physical blockages in pump lines |
| CA441 | Battery voltage too low | Weak battery, failing alternator, or loose/corroded battery cables | Check battery charge state, inspect alternator output, and tighten all power connections |
| CA122 | Intake air pressure sensor feedback voltage too high | Faulty intake pressure sensor or shorted wiring harness | Verify the intake pressure sensor operation and inspect the wiring for shorts |
| CA123 | Intake air pressure sensor feedback voltage too low | Sensor short to ground, airflow restriction, or disconnected sensor | Check for sensor short circuits and inspect for physical airflow restrictions in the intake system |
| CA153 | Intake air temperature sensor feedback voltage too high | Faulty Intake Air Temperature (IAT) sensor or open circuit | Test the IAT sensor resistance and replace if out of specification |
| CA154 | Intake air temperature sensor feedback voltage too low | Faulty IAT sensor or shorted circuit | Replace or test the IAT sensor for proper voltage output |
| CA234 | Engine overspeed | Throttle calibration error, excessive engine load cycle, or operator misuse | Verify throttle calibration and review engine load cycles for mechanical binding |
| CA442 | Battery voltage too high | Failing voltage regulator, bad alternator, or battery issue | Replace the alternator or battery and check the voltage regulator operation |
Codes and remedies are general guidance for this model family — always confirm with diagnostic tooling and your dealer before major repairs.
S4D105-1C(S/N 19078-UP) attachments & work tools
Crawler Dozer Blade Configurations
The S4D105-1C engine (S/N 19078-Up) powers the D45A-1, D45P-1, and D45S-1 crawler dozers. These machines utilize standard straight or angle blade configurations typical of the D45 class, with blade widths and cut angles varying by specific machine series and factory build options.
Wheeled Excavator Attachments
The S4D105-1C engine is not listed as a powerplant for the PW100-3 wheeled excavator in the provided equipment guide; that model utilizes the S6D95L-1D or S6D95L-1W engines. Consequently, specific work-tool compatibility data for the PW100-3 cannot be derived for the S4D105-1C engine from the source text.
Hydraulic System Fluid Specifications
Komatsu hydraulic systems require Komatsu Hydraulic Oil (HO) or equivalent ISO VG46/56 fluids meeting KES 07.841.1 specifications. The factory spec sheet for the 105 Series engine range indicates the use of Komatsu Genuine Lubricants to ensure proper seal compatibility and pump longevity.
Engine Cooling and Lubrication Capacities
For the S4D105 engine series applied to D40 and D45 class machines, the engine coolant capacity is approximately 22 liters (varies by machine series), and the engine oil capacity is approximately 13 liters. These figures are drawn from the Komatsu 105 Series Diesel Engine Shop Manual (SEBE6130A04) and may vary based on the specific machine's auxiliary cooling requirements.
Engine Identification and Serial Verification
The S4D105-1C engine is identified by serial number 19078-Up. The engine data plate is located on the left side of the engine block. Verification of the exact engine model requires checking the plate for the model name and arrangement number, as the final letter suffix identifies specific application variants not detailed in general guides.
All S4D105-1C(S/N 19078-UP) assemblies by section
Every catalogued assembly group for the Komatsu S4D105-1C(S/N 19078-UP). Open an assembly to preview the parts inside — full OEM part numbers are available in Heavy Parts AI.
Cooling And Electrical Systems
Komatsu : S4d105-1c(S/N 19078-Up) : Cooling And Electrical Systems : Alternator
Komatsu : S4d105-1c(S/N 19078-Up) : Cooling And Electrical Systems : Alternator (800w)
| 60***70 | Alternator A | 1 |
| KD***40 | Front Bracket A | 1 |
| KD***80 | Plate | 2 |
Komatsu : S4d105-1c(S/N 19078-Up) : Cooling And Electrical Systems : Alternator And Mounting
| 01***25 | Bolt,(Sandy? Dusty Terrain Spec.) | 1 |
| 01***40 | Bolt,(Dust And Dirt Protection) | 1 |
| 01***55 | Bolt,(For Suction? Reversible Fan) | 1 |
Komatsu : S4d105-1c(S/N 19078-Up) : Cooling And Electrical Systems : Safety Relay And Resistor
| 60***30 | Resistor | 1 |
| 60***10 | Regulator Ass'Y,For 35a Alternator (Not Shown) | 1 |
| 60***30 | Safety Relay A.,(A)(W/After Cooler)(S6d155-4b) | 1 |
Komatsu : S4d105-1c(S/N 19078-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 |
| 60***70 | Starting Motor A.,(See Fig.545) | 1 |
Komatsu : S4d105-1c(S/N 19078-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 : S4d105-1c(S/N 19078-Up) : Cooling And Electrical Systems : Starting Motor(#19078-.)
Komatsu : S4d105-1c(S/N 19078-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 : S4d105-1c(S/N 19078-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 : S4d105-1c(S/N 19078-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 : S4d105-1c(S/N 19078-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 : S4d105-1c(S/N 19078-Up) : Cylinder Block : Cylinder Block
| 01***55 | Bolt,(For Suction? Reversible Fan) | 4 |
| 01***65 | Bolt | 3 |
| 04***14 | Pin, Dowel | 2 |
Komatsu : S4d105-1c(S/N 19078-Up) : Cylinder Block : Flywheel And Flywheel Housing
| 01***14 | Bolt | 3 |
| 01***18 | Bolt | 6 |
| 01***25 | Bolt,(Sandy? Dusty Terrain Spec.) | 17 |
Komatsu : S4d105-1c(S/N 19078-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 : S4d105-1c(S/N 19078-Up) : Cylinder Block : Oil Pan
| 01***16 | Bolt,(For Slag Handling) | 2 |
| 01***20 | Bolt,(Large Capacity Type) (Std) | 1 |
| 01***25 | Bolt,(Sandy? Dusty Terrain Spec.) | 28 |
Komatsu : S4d105-1c(S/N 19078-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 : S4d105-1c(S/N 19078-Up) : Cylinder Head : Air Intake Connection And Air Cleaner
| 01***22 | Bolt,(Cold Terrain Spec.) | 3 |
| 01***25 | Bolt,(Without Auto Priming System) | 4 |
| 01***30 | Bolt,(Cold Terrain Spec.) | 3 |
Komatsu : S4d105-1c(S/N 19078-Up) : Cylinder Head : Compression Release
| 01***20 | Bolt,(Sandy? Dusty Terrain Spec.) | 1 |
| 01***25 | Bolt,(Without Auto Priming System) | 1 |
| 01***05 | Nut (Welded) | 1 |
Komatsu : S4d105-1c(S/N 19078-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 : S4d105-1c(S/N 19078-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 : S4d105-1c(S/N 19078-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 : S4d105-1c(S/N 19078-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 : S4d105-1c(S/N 19078-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 : S4d105-1c(S/N 19078-Up) : Cylinder Head : Water Pipe And Thermostat
| 01***18 | Bolt | 3 |
| 01***22 | Bolt,(Cold Terrain Spec.) | 9 |
| 01***35 | Bolt,(Without Auto Priming System) | 3 |
Fuel System
Komatsu : S4d105-1c(S/N 19078-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 : S4d105-1c(S/N 19078-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 : S4d105-1c(S/N 19078-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 : S4d105-1c(S/N 19078-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 : S4d105-1c(S/N 19078-Up) : Fuel System : Fuel Injection Pump And Piping
| 01***16 | Bolt (Welded) | 1 |
| 01***18 | Bolt | 4 |
| 01***20 | Bolt,(Sandy? Dusty Terrain Spec.) | 10 |
Komatsu : S4d105-1c(S/N 19078-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 : S4d105-1c(S/N 19078-Up) : Fuel System : Thermostat And Piping(#19078-24988)
| 01***12 | Bolt (M8-1.25x12) | 3 |
| 01***22 | Bolt,(Cold Terrain Spec.) | 3 |
| 01***25 | Washer,Spring?(Sandy And Dusty Spec.) | 6 |
Komatsu : S4d105-1c(S/N 19078-Up) : Fuel System : Thermostat And Piping(#24989-)
| 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 : S4d105-1c(S/N 19078-Up) : Lubricating Oil System : Lubricating Oil Cooler
Komatsu : S4d105-1c(S/N 19078-Up) : Lubricating Oil System : Lubricating Oil Filter
| 01***30 | Bolt,(For France Noise Suppression) | 1 |
| 01***80 | Bolt, Mount Strainer Flange | 2 |
| 01***04 | Nut | 2 |
Komatsu : S4d105-1c(S/N 19078-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 : S4d105-1c(S/N 19078-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 : S4d105-1c(S/N 19078-Up) : Lubricating Oil System : Turbocharger Lubricating Oil Piping
| 01***20 | Bolt,(Sandy? Dusty Terrain Spec.) | 2 |
| 01***22 | Bolt,(Cold Terrain Spec.) | 2 |
| 01***25 | Washer,Spring?(Sandy And Dusty Spec.) | 4 |
Tool And Kit
Komatsu : S4d105-1c(S/N 19078-Up) : Tool And Kit : Gasket Kit
| 01***12 | Washer,Lock (K2) | 1 |
| 01***08 | Washer,Lock (Kit) | 1 |
| 01***16 | Washer,Lock (K2) | 1 |
S4D105-1C(S/N 19078-UP) serial number reference
The engine serial number plate is located on the left side of the engine block or on a metal data plate affixed near the valve cover. The prefix is identified by the engine model code stamped on this plate, which for this range is S4D105-1C. Cross-reference this code with the machine's chassis serial number to confirm the specific equipment family (e.g., D45 dozer series) and configuration.
| Prefix | Identifies | Notes |
|---|---|---|
| S4D105-1C | Engine Model | 4-cylinder inline, turbocharged, water-cooled diesel engine. Serial range 19078-UP. Factory spec sheet for this engine series lists D45A-1, D45P-1, and D45S-1 dozers as applicable machine models. No specific 3-character PIN prefix is documented for this engine serial range in the provided sources; the model code itself serves as the primary identifier for parts cataloging. Verify with your dealer for specific machine PIN prefixes associated with this engine build range. |
Frequently asked questions
What engine does the Komatsu S4D105-1C use?
The Komatsu S4D105-1C is a four-cylinder diesel engine from the Komatsu 105 Series, featuring a turbocharged and aftercooled design. It is specifically designated for serial numbers 19078 and up.
What is the operating weight of the machine powered by this engine?
The operating weight varies by configuration and attachment package. For the D45A-1, D45P-1, and D45S-1 dozers equipped with this engine, the weight typically ranges from 20,000 to 60,000 lbs depending on the specific model variant and undercarriage setup.
What engine replaced the S4D105-1C?
The S4D105-1C was succeeded by the S4D105-3C engine, which applies to serial numbers 44579 and up. This newer generation incorporates updated emissions technology and performance enhancements while maintaining the 105 Series architecture.
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