Komatsu 4D105-3C(S/N 40138-UP)
Maintenance schedule, common problems & OEM parts breakdown
The 4D105-3C(S/N 40138-UP) designates a Komatsu 105-series inline four-cylinder, water-cooled, naturally aspirated diesel engine block: 105 x 125 mm bore and stroke, 4.33 L displacement, rated near 47 kW (63 hp) at 2,350 rpm, with mechanical fuel-injection governing and no ECM or digital diagnostics. Komatsu factory-fitted this block to its D31-16-series small crawler dozer and loader family: the D31A-16 straight dozer, the D31P-16 power-angle-tilt dozer, and the D31S-16/D31Q-16 crawler loader/shovel configurations, built roughly 1979 to 1986. All variants share a mechanical 3-speed-forward/3-speed-reverse planetary transmission with no torque converter or powershift, and operating weight spans roughly 5.2-7.1 t (11,400-15,550 lb) depending on the blade or bucket configuration fitted.
The S/N 40138-UP break marks a mid-production running change within the 3C block itself, not a new engine family: Komatsu used serial breaks like this to track updates to castings, injection components, and machined tolerances without renaming the engine. The wider D31-16 series was succeeded in the late 1980s by the D31-17 generation, which moved to the related 4D105-5 engine block rated slightly higher, before Komatsu eventually re-engineered the D31 line around hydrostatic-drive EX/PX designs decades later. In today's parts market, this page catalogs the engine block and its confirmed D31-16-family host chassis: on a machine this old, matching the exact engine serial break, not just the dash-number chassis model, is what determines correct gasket, injection pump, and machined-component fitment.
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 4D105-3C(S/N 40138-UP) specifications
Identification
| Model / serial break | 4D105-3C, S/N 40138 and up |
| Type | Komatsu 105-series inline 4-cylinder, water-cooled diesel engine model and serial block -- not a standalone machine chassis with its own PIN |
| Model code | 4 = cylinder count, D = inline vertical layout, 105 = bore in mm, -3C = generation/spec suffix for this build; 40138 marks the start of this production serial run |
Engine
| Bore x stroke | 105 mm x 125 mm (4.13 in x 4.92 in) |
| Displacement | 4.33 L (264 cu in) |
| Aspiration | Naturally aspirated as fitted to dozer/loader chassis for this model block. Turbocharged 105-series derivatives exist under a different engine model and are not this one |
| Net power, as installed | 47 kW / 63 hp (SAE) at approximately 2,350 rpm, as fitted to the D31-16 series chassis |
| Cooling | Liquid-cooled, engine-driven fan and radiator |
| Fuel system | Mechanical inline injection pump with per-cylinder injectors |
| Approx. engine dry weight | About 540 kg (1,190 lb) -- typical figure for this 105-series block; not separately confirmed for this exact serial run |
| Approx. engine size | Roughly 986 mm (38.8 in) long, 1,375 mm (54.1 in) tall including silencer -- family-typical figure |
Host machine applications
| Confirmed dozer/loader chassis | Factory-fitted to the Komatsu D31-16 series: D31A-16 and D31P-16 crawler dozers, D31S-16 and D31Q-16 crawler shovel/loaders, built roughly late 1970s to mid-1980s |
| Broader family note | Parts cross-references also tie this engine block to other same-era small/medium Komatsu dozers in the D31 through D45 weight class. Machine-level specs for those additional chassis are not detailed here -- confirm the exact host with a dealer using the engine data plate |
Weights (D31-16 series, by configuration)
| D31A-16 crawler dozer | 5.18 t (11,420 lb) operating weight |
| D31P-16 crawler dozer | 6.70 t (14,771 lb) operating weight |
| D31S-16 crawler shovel/loader | 6.68 t (14,727 lb) operating weight |
| D31Q-16 crawler shovel/loader | 7.05 t (15,550 lb) operating weight |
| Note | Weight varies by blade/bucket, track shoe, and rear drawbar/counterweight/winch option fitted |
Dimensions (D31-16 series, by configuration)
| Track gauge -- D31A-16 / D31P-16 / D31S-16 | 1.45 m (57.1 in) |
| Track gauge -- D31Q-16 | 1.65 m (65.0 in), wider-gauge loader configuration |
| Standard track shoe width -- D31A-16 / D31S-16 | 330 mm (13 in) |
| Standard track shoe width -- D31P-16 / D31Q-16 | 600 mm (23.6 in), wide low-ground-pressure shoe |
| Length without blade -- D31A-16 | 2.84 m (9.31 ft) |
| Length with blade / without blade -- D31P-16 | 3.85 m (12.64 ft) with blade; 3.03 m (9.95 ft) without |
| Width over tracks -- D31A-16 / D31S-16 | 1.79 m (5.88 ft) |
| Width over tracks -- D31P-16 | 2.05 m (6.73 ft) |
| Width over tracks -- D31Q-16 | 2.25 m (7.39 ft) |
| Ground clearance -- D31P-16 | 387 mm (1.27 ft) |
Performance (D31-16 series, by configuration)
| Transmission | Mechanical planetary-gear, 3 speeds forward / 3 speeds reverse. No torque converter or powershift on this series |
| Travel speed, forward | 6.6 km/h (4.1 mph), consistent across the D31-16 series |
| Travel speed, reverse | 7.2 km/h (4.5 mph) |
| Ground pressure -- D31P-16 (dozer, narrow shoe) | 0.22 kg/cm2 (3.12 psi) |
| Ground pressure -- D31Q-16 (loader, wide shoe) | 0.31 kg/cm2 (4.41 psi) |
| Ground pressure -- D31A-16 | 0.42 kg/cm2 (5.97 psi) |
| Ground pressure -- D31S-16 | 0.54 kg/cm2 (7.68 psi) |
| Drawbar pull -- D31P-16 | Approximately 53.4 kN (12,015 lbf) per factory spec sheet; treat as an approximate figure and confirm with a dealer for this exact configuration |
| Gradeability | Not published in available spec sheets for this serial range -- confirm with a dealer |
Blades (D31-16 series dozer configurations)
| D31A-16 standard blade | Width 2.44 m (8.0 ft), height 747 mm (29.4 in), cutting depth 366 mm (14.4 in); capacity not published |
| D31P-16 standard blade | Width 2.50 m (8.2 ft), height 782 mm (30.8 in), capacity 1.53 m3 (2.0 yd3), cutting depth 350 mm (13.8 in) |
| Loader configurations | D31S-16 and D31Q-16 carried a front bucket, about 0.84 m3 (1.1 yd3) heaped, in place of a dozing blade -- not comparable to blade capacity |
Service capacities
| Fuel tank | 115 L (30.4 US gal), consistent across the D31-16 series |
| Cooling system | 22.3 L (5.9 US gal), consistent across the D31-16 series |
| Engine oil | Not confirmed for this exact serial block. A related turbocharged 105-series engine variant lists about 13 L -- verify against the shop manual for this specific model/serial range before servicing |
| Hydraulic / transmission oil | Not documented in available spec sheets for this serial range -- consult the applicable D31-16 shop manual |
Values vary by configuration, region, and serial range — confirm against your machine before planning transport or lifts.
4D105-3C(S/N 40138-UP) fluids & capacities
| System | Capacity | Recommended fluid |
|---|---|---|
| Engine crankcase, with filter | Approx. 13 L (13.7 US qt / 11.4 imp qt), per the naturally aspirated 4D105-3 engine family's own spec table, which groups the 4D105-3, -3C, -3D and -3G builds together at this figure; treat as approximate and confirm against the OMM for this exact serial range. Turbocharged siblings of the same engine generation take more (around 18 L) -- do not use that figure for this block. | Diesel engine oil, API CD/CC service class typical for this engine's era. Viscosity is selected by ambient temperature (commonly SAE10W in cold weather, SAE30 in warm weather, or a 10W-30/15W-40 multigrade for a broader range), but the exact chart for this engine was not accessible in available sources -- confirm against the OMM before servicing. |
| Cooling system | 22.3 L (5.9 US gal / 4.9 imp gal). Consistent across the D31-16 chassis series (D31A-16, D31P-16, D31S-16, D31Q-16) this engine block was fitted to, and matches the coolant figure in the engine family's own spec table. | Ethylene-glycol antifreeze/coolant mixed with clean soft water. Use a permanent (all-season) antifreeze for corrosion and freeze protection; set the mix ratio by the lowest expected ambient temperature. |
| Fuel tank | 115 L (30.4 US gal / 25.3 imp gal). Consistent across the D31-16 chassis series. | No. 2-D diesel fuel for normal and warm ambient conditions. Switch to No. 1-D (lighter, better cold-flow) diesel in cold weather. |
| Transmission (main gear case) | Not documented in available sources for this exact serial range. The D31-16 chassis series this engine block was fitted to used a mechanical planetary-gear transmission -- 3 speeds forward, 3 speeds reverse -- with no torque converter or powershift, so capacity/fluid figures published for hydraulically-shifted transmissions under other D31 nameplates do not apply to this machine. | Not documented for this exact serial range -- consult the shop manual covering this specific chassis before servicing. |
| Bevel gear / steering clutch compartment | Not documented in available sources for this exact serial range. | Not documented for this exact serial range -- consult the shop manual before servicing. Note: some machines built under the same D31-16 nameplate range (for example a later "-16A" running change) are described elsewhere as carrying a power-shift transmission instead of the mechanical gearbox confirmed for the base series. Verify the exact model suffix and transmission type on the machine before assuming fluid type or capacity. |
| Final drives, each side | Not documented in available sources for this exact serial range. | Not documented -- consult the shop manual. Sources note a drain plug at each side's steering/bevel case for oil renewal, but a separate final-drive oil quantity distinct from the bevel gear compartment was not found. |
| Hydraulic system / equipment tank | Not documented in available sources for this exact serial range. | Not documented. On power-angle-tilt (PAT) blade configurations the machine carries a hydraulic reservoir for blade lift/angle/tilt cylinders, but no oil type or quantity was found for this configuration -- confirm with a dealer or the OMM. |
| Pivot (equalizer) shaft | Not documented in available sources for this exact serial range. | Not documented. Compact track-frame dozers of this class commonly grease the equalizer/pivot point at a fitting rather than fill it with oil, but this was not specifically confirmed for the D31-16 series -- confirm against the OMM. |
| Grease points (chassis lubrication) | No bulk reservoir. Applied at individual grease fittings (track adjuster, idlers, pins and bushings, steering linkage) until fresh grease purges from the joint. | Multipurpose lithium-base chassis grease, NLGI grade 2, typical of Komatsu practice for this era; a molybdenum-disulfide lithium-base grease is commonly specified for heavily loaded pin and bushing joints on equipment of this class. The specific Komatsu grease designation was not confirmed for this exact serial range in available sources. |
Capacities are refill values from factory literature — always fill to the dipstick/sight gauge, not the number.
Komatsu 4D105-3C(S/N 40138-UP) maintenance schedule
| Service interval | Tasks |
|---|---|
| Every 10 h |
|
| Every 250 h |
|
| Every 500 h |
|
| Every 1,000 h |
|
| Every 2,000 h |
|
| Every 4,000 h |
|
Servicing the 4D105-3C(S/N 40138-UP) beyond the schedule
Predictive Maintenance & Fluid Analysis
This 4D105-3C runs mechanical governing with no ECM, so there are no fault codes to monitor. Condition tracking here means physical sampling: pull engine oil at each interval to catch injection pump and cylinder liner wear early, and watch coolant condition for head gasket or wet-liner seepage. The mechanical injection pump and governor linkage are the engine's main control point, so track exhaust smoke color and idle behavior as leading indicators. Sample steering-clutch and transmission case oil for metal fines before wear reaches the planetary gearset.
Corrective & Common Repairs
Common wear points on this engine and its D31-16 host chassis center on age and mechanical wear, not electronics. Expect injection pump and injector calibration drift, water pump seal and gasket leaks, and worn starter/alternator brushes on engines this old. On the chassis side, steering clutch and brake band wear cause pull or drag, final drive seals weep with age, and track pins, bushings, and idlers on a 1979-1986 machine are commonly worn past service limits. Wiring and fuel lines this old also warrant a full visual inspection before troubleshooting.
Overhaul & Rebuild Points
At major-hours rebuild, measure cylinder bore and piston ring wear against factory limits, check crankshaft bearing clearances, and bench-test or recalibrate the mechanical injection pump before reinstalling it. Resurface the cylinder head and reseat valves as needed, since this engine has no aftercooler margin to mask combustion wear. On the D31-16 chassis, plan steering clutch pack and brake band relining, inspect planetary transmission gears and bearings for pitting, and overhaul final drive gearsets alongside track and roller wear on machines this old.
Seasonal & Environment Servicing
Cold climates: check coolant antifreeze concentration and battery electrolyte before winter, since this naturally aspirated engine has no ECM-controlled cold-start aids to offset weak charge or thin coolant. Use winter-grade diesel to avoid fuel waxing in the mechanical injection system. Hot or dusty sites: clean the radiator core often, since there is no aftercooler margin to absorb intake heat, and service the air cleaner more frequently than the standard interval. In wet or muddy ground, drain fuel tank sediment more often and adjust track tension for the terrain.
4D105-3C(S/N 40138-UP) common service parts
| Part number | Part | Notes | |
|---|---|---|---|
| 6130-72-6100 | Fuel Filter Ass'Y | Fuel system service | Check fitment → |
| 600-211-6230 | Cartridge,(For Oil Filter) | Lubrication service | Check fitment → |
| 6127-61-2971 | O-Ring,Oil Cooler Element | Lubrication service | Check fitment → |
| 6130-52-5100 | Oil Filter Ass'Y | Lubrication service | Check fitment → |
| 6130-52-5101 | Oil Filter Ass'Y | Lubrication service | Check fitment → |
Always confirm against your machine's serial number — cross-check any part in Heavy Parts AI before ordering.
4D105-3C(S/N 40138-UP) fault codes & troubleshooting
| Code | Meaning | Likely cause | What to do |
|---|---|---|---|
| CHARGE lamp (red, battery symbol) | Charging circuit not producing sufficient voltage | Failed alternator or regulator, slipping/broken fan-alternator belt, loose or corroded wiring | Check belt tension and wiring, test alternator output, replace regulator or alternator as needed |
| Engine oil pressure lamp (red, oil-can symbol) | Engine oil pressure below safe minimum | Low oil level, worn oil pump, clogged filter or strainer, failed pressure switch, worn bearings | Stop engine immediately, check oil level and for leaks, inspect filter and pressure switch before restarting |
| Coolant temperature gauge (red zone) | Engine coolant temperature above normal operating range | Low coolant level, clogged radiator core, failed thermostat, slipping fan belt | Idle down and let engine cool, check coolant level and radiator for debris or leaks, check fan belt and thermostat |
| Air cleaner restriction indicator | Air intake filter element heavily clogged, restricting airflow | Dust-loaded or damaged filter element, blocked pre-cleaner | Inspect and clean or replace the air filter element, check intake ducting for damage |
Codes and remedies are general guidance for this model family — always confirm with diagnostic tooling and your dealer before major repairs.
4D105-3C(S/N 40138-UP) attachments & work tools
Blades
This engine range powers Komatsu's small-to-medium dozer family (D31 through D45 series, roughly 6.7-10 t / 14,700-22,000 lb operating class). Straight (S) and angling (A) blades are the base factory choices; semi-U (SU) blades add wing extensions for more load capacity but give up some penetration versus a straight blade. A power-angle-tilt blade -- Komatsu calls this PAT, not the Caterpillar-trademarked VPAT term -- was also cataloged on this class, letting the operator adjust lift, angle, and tilt hydraulically; blade widths run roughly 2.3-2.7 m (7.5-9 ft) depending on model and blade type.
Rippers
This class typically used a multi-shank parallelogram ripper (commonly 3-shank with twin hydraulic cylinders) rather than a single giant single-shank ripper, which is reserved for larger dozer classes. Complete multi-shank ripper assemblies sized for this family run roughly 470-720 kg (1,035-1,590 lb) depending on beam/shank count; a single-shank ripper is not a typical factory offering at this weight class.
Winches
Dozers in this weight class commonly carried a PTO-driven cable winch in the roughly 13-14 tonne (about 30,000 lb) line-pull class, mounted at the rear in place of the drawbar/counterweight. Winch packages built for this chassis family are documented for the era-correct D31/D37/D39-type frame; exact pull rating and drum size scale with which specific chassis (D31 vs. the larger D40/D45) the engine is fitted to.
Drawbars/counterweights
A rear drawbar and a bolt-on slab counterweight bracket are alternate rear-end fitments on this family, sharing the same mounting point used by the winch. Without a drawbar, slab ballast stacks in roughly 45 kg (98 lb) increments to tune total weight from about 340 kg to 600 kg (750-1,300 lb); the drawbar version covers a similar adjustable range. Only one rear fitment (drawbar, counterweight, or winch) mounts at a time.
Cab/ROPS guarding
Factory cab on this family is an open ROPS canopy (steel or fiberglass rain canopy) meeting ROPS/FOPS structural standards; dedicated factory forestry guarding (screened doors, top FOPS mesh, belly and root guards) was not a standard catalog item on this small-dozer generation. Aftermarket ROPS canopies and forestry screen/guard kits sized to this chassis are available and are commonly fitted for brush-clearing or waste-handling duty.
Hydraulic arrangement (front/rear tools)
Blade (lift/angle/tilt) hydraulics up front and ripper or winch hydraulics at the rear run as separate circuits off the same engine-driven pump. System relief on this family's circuit is set around 27.4 MPa (280 kgf/cm2, about 3,980 psi). Running a rear winch requires the optional winch hydraulic/PTO package to be fitted; it is not present on a base dozer-and-blade-only configuration, so winch and ripper are not both hydraulically live unless the machine was ordered or retrofitted with the extra circuit.
All 4D105-3C(S/N 40138-UP) assemblies by section
Every catalogued assembly group for the Komatsu 4D105-3C(S/N 40138-UP). Open an assembly to preview the parts inside — full OEM part numbers are available in Heavy Parts AI.
Cooling And Electrical Systems
Komatsu : 4d105-3c(S/N 40138-Up) : Cooling And Electrical Systems : Alternator
| 60***10 | Alternator A. (25a) | 1 |
| KD***30 | Holder,Brush | 1 |
| KD***72 | Slip Ring Ass'Y | 1 |
Komatsu : 4d105-3c(S/N 40138-Up) : Cooling And Electrical Systems : Alternator (For Trimming Dozer)
| 60***80 | Alternator A. (13a) | 1 |
| KD***30 | Holder,Brush | 1 |
| KD***72 | Slip Ring Ass'Y | 1 |
Komatsu : 4d105-3c(S/N 40138-Up) : Cooling And Electrical Systems : Alternator And Mounting
| 01***40 | Bolt,(Dust And Dirt Protection) | 1 |
| 01***30 | Bolt,(For Trimming Dozer) | 1 |
| 01***25 | Bolt | 1 |
Komatsu : 4d105-3c(S/N 40138-Up) : Cooling And Electrical Systems : Emergency Relay And Resistor
| 60***70 | Switch,Air Intake Heater | 1 |
| 60***60 | Switch,Heater Relay | 1 |
| 61***50 | Resistor | 1 |
Komatsu : 4d105-3c(S/N 40138-Up) : Cooling And Electrical Systems : Starting Motor (#42792-..)
| 60***41 | Starting Motor Ass'Y,(See Fig.1545) | 1 |
| 60***42 | Starting Motor A.,(5.5kw) (See Fig.2546) | 1 |
| KD***10 | Clutch Ass'Y,Over Running | 1 |
Komatsu : 4d105-3c(S/N 40138-Up) : Cooling And Electrical Systems : Starting Motor (1/2)(#..-)
| 60***43 | Starting Motor A.,(5.5kw) (See Fig.0661) | 1 |
| KD***10 | Clutch Ass'Y,Over Running | 1 |
| KD***01 | O-Ring | 1 |
Komatsu : 4d105-3c(S/N 40138-Up) : Cooling And Electrical Systems : Starting Motor (2/2)(#..-)
| KD***01 | Washer,Seal | 3 |
| KD***80 | Shift Lever Ass'Y | 1 |
| KD***30 | Contactor,Moving | 1 |
Komatsu : 4d105-3c(S/N 40138-Up) : Cooling And Electrical Systems : Starting Motor (For Trimming Dozer)
| 60***51 | Starting Motor A | 1 |
| KD***10 | Clutch Ass'Y,Over Running | 1 |
| KD***80 | Field Coil Ass'Y | 1 |
Komatsu : 4d105-3c(S/N 40138-Up) : Cooling And Electrical Systems : Starting Motor And Mounting
| 01***35 | Bolt - Torque Converter Totransmission Mounting | 3 |
| 01***36 | Washer, Spring | 3 |
| 07***00 | O-Ring,(F4350-65a1 -5 ) | 1 |
Komatsu : 4d105-3c(S/N 40138-Up) : Cooling And Electrical Systems : Starting Motor(#40138-42791)
| 60***40 | Starting Motor A.,(See Fig.1545) | 1 |
| 60***41 | Starting Motor A.,(See Fig.1545) | 1 |
| 60***42 | Starting Motor A | 1 |
Komatsu : 4d105-3c(S/N 40138-Up) : Cooling And Electrical Systems : Water Pump And Cooling Fan(#40138-47893)
| 01***16 | Bolt,(For Slag Handling) | 3 |
| 01***25 | Bolt,(Without Auto Priming System) | 6 |
| 01***30 | Bolt,(Cold Terrain Spec.) | 2 |
Komatsu : 4d105-3c(S/N 40138-Up) : Cooling And Electrical Systems : Water Pump And Cooling Fan(#47894-)
| 01***16 | Bolt,(For Slag Handling) | 3 |
| 01***25 | Bolt,(Without Auto Priming System) | 6 |
| 01***30 | Bolt,(Cold Terrain Spec.) | 8 |
Cylinder Block
Komatsu : 4d105-3c(S/N 40138-Up) : Cylinder Block : Camshaft And Tappet(#40138-40495)
| 01***18 | Bolt | 2 |
| 01***25 | Bolt,(Sandy? Dusty Terrain Spec.) | 2 |
| 01***25 | Washer,Spring?(Sandy And Dusty Spec.) | 2 |
Komatsu : 4d105-3c(S/N 40138-Up) : Cylinder Block : Camshaft And Tappet(#40496-)
| 01***18 | Bolt | 2 |
| 01***25 | Bolt,(Sandy? Dusty Terrain Spec.) | 2 |
| 01***25 | Washer,Spring?(Sandy And Dusty Spec.) | 2 |
Komatsu : 4d105-3c(S/N 40138-Up) : Cylinder Block : Crankshaft
| 01***30 | Bolt,(For France Noise Suppression) | 4 |
| 02***04 | Plug,(Not Shown) | 4 |
| 04***25 | Key | 1 |
Komatsu : 4d105-3c(S/N 40138-Up) : Cylinder Block : Cylinder Block
| 01***22 | Bolt,(Cold Terrain Spec.) | 2 |
| 01***30 | Bolt,Radio Controlled Slag Handling | 7 |
| 01***65 | Bolt | 3 |
Komatsu : 4d105-3c(S/N 40138-Up) : Cylinder Block : Flywheel And Flywheel Housing
| 01***25 | Bolt,(Sandy? Dusty Terrain Spec.) | 15 |
| 01***40 | Bolt,(Dust And Dirt Protection) | 5 |
| 01***35 | Bolt - Torque Converter Totransmission Mounting | 6 |
Komatsu : 4d105-3c(S/N 40138-Up) : Cylinder Block : Front Cover
| 01***45 | Bolt,(For Suction? Reversible Fan) | 7 |
| 01***75 | Bolt,(For D57sr) | 2 |
| 01***30 | Washer,Spring(Sandy?Dusty Terrain S.) | 9 |
Komatsu : 4d105-3c(S/N 40138-Up) : Cylinder Block : Oil Pan
| 01***25 | Bolt,(Sandy? Dusty Terrain Spec.) | 23 |
| 01***30 | Bolt,(For France Noise Suppression) | 2 |
| 01***35 | Bolt, Mounting - Flywheel Housing End | 1 |
Komatsu : 4d105-3c(S/N 40138-Up) : Cylinder Block : Piston And Connecting Rod
| 61***14 | Bolt | 2 |
| 61***15 | Bolt,(Service Parts) | 2 |
| 61***22 | Nut,(Service Parts) | 2 |
Cylinder Head
Komatsu : 4d105-3c(S/N 40138-Up) : Cylinder Head : Air Intake Connection And Air Cleaner(#40138-56494)
| 01***25 | Bolt,(Sandy? Dusty Terrain Spec.) | 2 |
| 01***80 | Bolt, Mount Strainer Flange | 2 |
| 01***30 | Washer,Spring(Sandy?Dusty Terrain S.) | 4 |
Komatsu : 4d105-3c(S/N 40138-Up) : Cylinder Head : Air Intake Connection And Air Cleaner(#56495-63805)
| 01***25 | Bolt,(Sandy? Dusty Terrain Spec.) | 2 |
| 01***80 | Bolt, Mount Strainer Flange | 2 |
| 01***30 | Washer,Spring(Sandy?Dusty Terrain S.) | 4 |
Komatsu : 4d105-3c(S/N 40138-Up) : Cylinder Head : Air Intake Connection And Air Cleaner(#63806-)
| 01***25 | Bolt,(Sandy? Dusty Terrain Spec.) | 2 |
| 01***70 | Bolt, Spacer | 2 |
| 01***30 | Bolt, Mount Control Valve | 2 |
Komatsu : 4d105-3c(S/N 40138-Up) : Cylinder Head : Cylinder Head
| 01***16 | Bolt,(For Slag Handling) | 6 |
| 01***25 | Bolt,(Sandy? Dusty Terrain Spec.) | 2 |
| 01***25 | Washer,Spring?(Sandy And Dusty Spec.) | 6 |
Komatsu : 4d105-3c(S/N 40138-Up) : Cylinder Head : Cylinder Head Cover(#40138-63805)
| 01***20 | Bolt,(Sandy? Dusty Terrain Spec.) | 2 |
| 01***50 | Bolt,(For Trimming Dozer) | 8 |
| 01***70 | Bolt | 4 |
Komatsu : 4d105-3c(S/N 40138-Up) : Cylinder Head : Cylinder Head Cover(#63806-)
| 01***20 | Bolt,(Sandy? Dusty Terrain Spec.) | 2 |
| 01***50 | Bolt,(For Trimming Dozer) | 8 |
| 01***70 | Bolt | 4 |
Komatsu : 4d105-3c(S/N 40138-Up) : Cylinder Head : Exhaust Manifold And Muffler
| 01***20 | Capscrew - M10 | 2 |
| 01***25 | Bolt, Mount Cover | 4 |
| 01***40 | Bolt, Mount Retainer | 8 |
Komatsu : 4d105-3c(S/N 40138-Up) : Cylinder Head : Rocker Arm
| 01***12 | Bolt,(Without R.P.C.U.) | 1 |
| 01***80 | Bolt,(Shim 5 Pieces Over) | 4 |
| 01***19 | Washer,(Not Used With Ventilator) | 1 |
Fuel System
Komatsu : 4d105-3c(S/N 40138-Up) : Fuel System : Fuel Filter And Mounting
| 01***35 | Bolt, Mounting - Flywheel Housing End | 2 |
| 01***30 | Washer,Spring(Sandy?Dusty Terrain S.) | 2 |
| 01***16 | Washer,Radio Controlled Slag Handling | 2 |
Komatsu : 4d105-3c(S/N 40138-Up) : Fuel System : Fuel Injection Pump (Feed Pump)
| 61***10 | Injection Pump Ass'Y,(See Fig.1451) | 1 |
| DK***00 | Tappet | 1 |
| DK***20 | Housing | 1 |
Komatsu : 4d105-3c(S/N 40138-Up) : Fuel System : Fuel Injection Pump (Governor) (1/2)
| 61***10 | Injection Pump Ass'Y,(See Fig.1451) | 1 |
| DK***00 | Gasket | 1 |
| DK***00 | Adapter | 1 |
Komatsu : 4d105-3c(S/N 40138-Up) : Fuel System : Fuel Injection Pump (Governor) (2/2)
| 61***10 | Injection Pump Ass'Y,(See Fig.1451) | 1 |
| DK***40 | Gasket,Air Compressor | 2 |
| DK***00 | Collar | 1 |
Komatsu : 4d105-3c(S/N 40138-Up) : Fuel System : Fuel Injection Pump (Pump)
| 61***10 | Injection Pump Ass'Y,(See Fig.1451) | 1 |
| 61***11 | Injection Pump Ass'Y | 1 |
| DK***20 | Plunger Ass'Y | 1 |
Komatsu : 4d105-3c(S/N 40138-Up) : Fuel System : Fuel Injection Pump And Piping
| 01***25 | Bolt (M6-1.00x25) | 1 |
| 01***35 | Stud | 6 |
| 01***35 | Stud | 4 |
Komatsu : 4d105-3c(S/N 40138-Up) : Fuel System : Fuel Nozzle And Spill Pipe
| 01***65 | Bolt | 8 |
| 07***12 | Gasket,Mechanical Pump Piping | 6 |
| 61***52 | Bolt, Joint | 1 |
Komatsu : 4d105-3c(S/N 40138-Up) : Fuel System : Intake Air Heater(#40138-63805)
| 01***16 | Bolt,(For Slag Handling) | 1 |
| 01***20 | Bolt,(Large Capacity Type) (Std) | 4 |
| 01***05 | Nut (Welded) | 2 |
Lubricating Oil System
Komatsu : 4d105-3c(S/N 40138-Up) : Lubricating Oil System : Lubricating Oil Filter(#40138-52218)
| 01***16 | Bolt,(For Slag Handling) | 8 |
| 01***25 | Bolt,(Without Auto Priming System) | 1 |
| 01***35 | Bolt, Mounting - Flywheel Housing End | 1 |
Komatsu : 4d105-3c(S/N 40138-Up) : Lubricating Oil System : Lubricating Oil Filter(#52219-)
| 01***16 | Bolt,(For Slag Handling) | 11 |
| 01***35 | Bolt, Mounting - Flywheel Housing End | 1 |
| 01***45 | Bolt,(For Suction? Reversible Fan) | 1 |
Komatsu : 4d105-3c(S/N 40138-Up) : Lubricating Oil System : Lubricating Oil Pump
| 01***30 | Bolt,(For France Noise Suppression) | 5 |
| 01***30 | Washer,Spring(Sandy?Dusty Terrain S.) | 5 |
| 01***16 | Washer,Radio Controlled Slag Handling | 5 |
Komatsu : 4d105-3c(S/N 40138-Up) : Lubricating Oil System : Lubricating Oil Strainer
| 01***25 | Bolt,(Without Auto Priming System) | 2 |
| 01***25 | Bolt,(Sandy? Dusty Terrain Spec.) | 2 |
| 01***08 | Nut, Regular Hexagon (M10-1.50) | 1 |
Tool And Kit
Komatsu : 4d105-3c(S/N 40138-Up) : Tool And Kit : Gasket Kit
| 01***23 | Washer,Lock (K2) | 1 |
| 07***65 | O-Ring,Injection Pump Case | 1 |
| 07***70 | O-Ring,(For Intake Air Cover) | 1 |
Frequently asked questions
What engine powers the machine this listing covers?
The Komatsu 4D105-3C(S/N 40138-UP) is itself the engine: an inline four-cylinder, water-cooled, naturally aspirated diesel with 105 x 125 mm bore and stroke, 4.33 L displacement, rated near 47 kW (63 hp) at 2,350 rpm. It uses mechanical fuel-injection governing with no ECM or digital diagnostics, and is the factory engine fitted to Komatsu's D31A-16, D31P-16, D31S-16, and D31Q-16 crawler dozer/loader models.
What is the operating weight of the host machine?
It varies by configuration. The straight-blade D31A-16 dozer runs about 5.2 t (11,420 lb); the power-angle-tilt D31P-16 and the D31S-16/D31Q-16 crawler loader configurations run heavier, roughly 6.7-7.1 t (14,700-15,550 lb), depending on the blade or bucket fitted.
What replaced this engine and its host dozer?
The D31-16 series was succeeded in the late 1980s by the D31-17 generation, which moved to the related 4D105-5 engine block rated slightly higher, around 66 hp (49 kW), while keeping the same naturally aspirated inline-four layout and mechanical planetary transmission. Komatsu later re-engineered the D31 line around hydrostatic-drive EX/PX designs.
What 4D105-3C(S/N 40138-UP) owners discuss
What do owners and mechanics say about cold starting and startup smoke on the 4D105-3C engine?
What steering clutch and drivetrain symptoms come up most for this dozer class?
What cooling system issues do owners report on this engine and dozer combination?
What electrical or charging issues are typical on this dozer?
What do owners report about oil consumption or crankcase blow-by on this engine?
What undercarriage wear pattern is typical for this weight class of dozer?
What should a buyer check before purchasing a used 4D105-3C-powered D31-16-class dozer?
Compiled from owner and technician discussions across the industry — experiences vary by serial range and machine history.
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