Komatsuengine(no series)
Komatsu 4D95S-1H(S/N 124813-UP)
Maintenance schedule, common problems & OEM parts breakdown
The 4D95S-1H (S/N 124813-up) is a mechanically-governed, naturally aspirated 2.69 L (164.2 cu in) four-cylinder diesel rated 29.8 kW (40 hp) gross at 2450 rpm, with no ECM or electronic controls. It is the engine fitted to Komatsu's D20-7A generation of small crawler dozers: the D20P-7A (direct-drive, wide-track dozer), D20PG-7A (wide-track dozer with grouser/attachment configuration), and D20PL-7 (crawler-loader front end on the same chassis). These machines fall in the roughly 3.9-4.0 tonne (8,700-8,900 lb) operating-weight class, Komatsu's smallest dozer line, built for confined-space grading, landscaping, and utility work rather than heavy production dozing. The -7A generation ran through the 1990s, following the D20/D21-6 series (mid-1980s to early 1990s) and preceding the D20/D21-8 generation that arrived around 2000. Some chassis in the same family were built instead with a 4D94E-1A engine, and a related hydrostatically-driven D21 sibling used the 4D95S-1J version of this same basic engine block on the same serial break.
Compared with the -6 series predecessor's 4D95S-W-1 engine, the -7 generation brought engine and control refinements, an optional joystick steering control, and, on later production, single-lever blade control. Across the wider 4D95 engine family the basic four-cylinder block and mechanical injection layout stayed consistent for decades even as individual chassis and governor calibrations changed, so parts commonality runs deep but calibration and injector specifics still vary by build. In the used and parts market today, the 4D95S-1H's simple mechanical fuel system and total lack of emissions hardware or electronics make it attractive to owners rebuilding older dozers without chasing modern DPF or ECM faults. Because the broader 4D95 engine line also powered forklifts, small excavators, and generator sets in far larger numbers, wear parts, injection components, and rebuild kits stay easier to source than the dozer chassis itself, which has been out of production for years.
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-1H(S/N 124813-UP) specifications
Engine
| Model / build | Komatsu 4D95S-1H (S/N 124813-UP), part of the 95-series short-stroke 4-cylinder diesel family. This exact serial break also covers the sister 4D95S-1J build for the companion hydrostatic-drive chassis; both succeeded the earlier W-prefixed 4D95S-W-1F/1G engine used on the prior generation of the same dozer line. |
| Type | 4-cylinder, inline, 4-cycle, water-cooled diesel |
| Aspiration / injection | Naturally aspirated, mechanical (jerk-pump) direct injection. A separate turbocharged 1J-T build exists in the same family for other equipment; this build is not turbocharged. |
| Displacement | 2.69 L (164 cu in / 2,691 cc), 95 mm bore |
| Gross power | 29.8 kW (40 hp) at 2,450 rpm gross, per the factory rating for the compact dozer chassis this engine build powers |
| Emissions tier | Not applicable - this is a mechanically governed design that predates nonroad diesel emissions-tier certification |
Weights
| Operating weight, as installed (direct-drive host chassis, this 1H build) | approx. 3,550 kg (7,827 lb) |
| Operating weight, as installed (hydrostatic-drive host chassis, sister 1J build) | approx. 3,600 kg (7,937 lb) |
Dimensions
| Overall length with blade (host chassis) | approx. 3.40-3.41 m (11.16-11.2 ft) |
| Overall length without blade | approx. 2.56 m (8.4 ft) |
| Width over tracks | approx. 1.61-1.62 m (5.29-5.3 ft) |
| Height to top of cab | approx. 2.48-2.50 m (8.13-8.2 ft) |
| Ground clearance | approx. 0.30 m (0.97-1.0 ft) |
| Track gauge | approx. 1.31 m (4.3 ft) |
| Track length on ground | approx. 1.685 m (5.53 ft) |
Performance
| Transmission and gears (direct-drive host, this 1H build) | 3 forward / 2 reverse gears |
| Transmission and gears (hydrostatic host, sister 1J build) | 2 forward / 2 reverse |
| Travel speed / drawbar | Not documented for this exact engine build - figures vary by the specific gear set and final drive fitted to the host machine; verify against the machine operator's manual |
Values vary by configuration, region, and serial range — confirm against your machine before planning transport or lifts.
4D95S-1H(S/N 124813-UP) fluids & capacities
| System | Capacity | Recommended fluid |
|---|---|---|
| Engine crankcase (with filter) | 6.6 L (1.74 US gal) on the D20P-7A and D20PL-7 dozer fit; 7.0 L (1.85 US gal) on the D20PG-7A fit - varies by chassis configuration | Komatsu Genuine engine oil (EO series). This is a pre-electronic, mechanically-governed diesel from the API CD/CE oil era; today's Komatsu-stocked equivalent is the 15W-40 low-ash diesel engine oil. Climate guide: SAE 10W below 0degC (32degF), SAE 30 or 15W-40 above 0degC. |
| Cooling system | 10.0 L (2.64 US gal) | Komatsu Genuine Super Coolant AF-NAC, a pre-mixed, long-life ethylene-glycol antifreeze/anti-corrosion coolant. Supplied pre-mixed for year-round use; no field dilution needed. |
| Fuel tank | 60.0 L (15.84 US gal) | Diesel fuel per ASTM D975 No. 2-D. Switch to No. 1-D or a winter-blend diesel in sub-freezing conditions to prevent fuel gelling in this mechanical inline-injection engine. |
| Transmission / steering-clutch case | 16.5 L (4.36 US gal) on the D20P-7A and D20PG-7A fit; 13.7 L (3.63 US gal) on the D20PL-7 fit - varies by chassis configuration | Komatsu Genuine TO30 powertrain oil, SAE 30W, API CD class. |
| Final drive, each side | 8.0 L (2.11 US gal) per side | Komatsu Genuine TO10 powertrain oil, SAE 10W, API CD class - same product family as the transmission fill, lighter grade. |
| Hydraulic system (blade-lift/steering circuit) | 21.0 L (5.54 US gal) | Komatsu Genuine HO46 hydraulic oil, ISO VG46 grade. |
| Grease (chassis, track idlers, blade and ripper pivots) | Not a bulk reservoir - applied per grease fitting at scheduled intervals | Komatsu Genuine multi-purpose grease, lithium EP base, NLGI 2. |
Capacities are refill values from factory literature — always fill to the dipstick/sight gauge, not the number.
Komatsu 4D95S-1H(S/N 124813-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 4D95S-1H(S/N 124813-UP) beyond the schedule
Predictive Maintenance & Fluid Analysis
This 4D95S-1H has no ECM or diagnostic codes, so condition monitoring relies on oil sampling and analog gauges. Pull engine oil (Komatsu EO) samples at oil-change intervals and watch for metal or fuel dilution signaling injection pump or ring wear. Track coolant (AF-NAC) condition to catch corrosion before it reaches the block. Watch dash lamps for oil pressure and coolant temperature drift, and log final drive and transmission oil (TO10/TO30) condition each drain to catch steering clutch or gear wear early.
Corrective & Common Repairs
Typical fixes on this powertrain center on the mechanical injection pump and governor, diagnosed injector-by-injector rather than through fault codes. Rough idle or hard cold starts usually trace to a weak glow plug/preheat circuit or a fouled injector, not electronics. Blade-lift cylinder seals wear and weep over time and need reseal kits. Dry steering-clutch housings can stick after long idle periods; free and relube before returning the dozer to work rather than forcing the lever.
Overhaul & Rebuild Points
Major rebuild points on the 4D95S-1H fall at valve clearance and injection-timing resets, injection pump/governor overhaul, and head reconditioning once compression or smoke signals wear. Undercarriage components (track rollers, idlers, and sprockets) wear at rates typical for this roughly 4-tonne dozer class and are usually replaced as a set rather than piecemeal. Steering clutch discs and brake bands, along with final drive gearing, are the other common rebuild targets on high-hour machines.
Seasonal & Environment Servicing
Cold-weather starts depend entirely on the glow plug/preheat system since there is no electronic cold-start assist; test it before winter and keep the coolant (AF-NAC) mixed for the expected low. Machines parked idle over a season are prone to sticking dry steering-clutch housings on restart, so cycle the clutches and brakes before working the blade. In hot, dusty conditions check the wet-type air cleaner and radiator fins more often than the standard interval to protect the naturally aspirated engine from dust ingestion and overheating.
4D95S-1H(S/N 124813-UP) common service parts
| Part number | Part | Notes | |
|---|---|---|---|
| 600-311-1190 | Plate? Caution,Fuel Filter | Fuel system service | Check fitment → |
| 09637-90263 | Plate? Instruction,Air Cleaner Element Mainte | Air intake service | Check fitment → |
| 09637-30161 | Plate? Instruction,Air Cleaner (Single Element) | Air intake service | Check fitment → |
| 09637-30163 | Plate? Instruction,Air Cleaner (Single Element) | Air intake service | Check fitment → |
| 09637-30262 | Plate? Instruction,Air Cleaner (Double Element) | Air intake service | Check fitment → |
Always confirm against your machine's serial number — cross-check any part in Heavy Parts AI before ordering.
4D95S-1H(S/N 124813-UP) fault codes & troubleshooting
| Code | Meaning | Likely cause | What to do |
|---|---|---|---|
| Oil pressure warning lamp (red) | Engine oil pressure below the safe minimum threshold | Low oil level, worn oil pump, clogged filter, or failed pressure sender | Stop engine immediately, check oil level and filter, verify sender before restart |
| Coolant temperature warning lamp (red) | Engine coolant temperature above normal operating range | Low coolant level, blocked radiator fins, slipping or broken fan belt, faulty thermostat | Idle down, let engine cool, check coolant level and belt tension, inspect radiator for debris |
| Charge (alternator) warning lamp (red) | Charging system not producing correct output | Broken or slipping fan belt, faulty alternator, loose or corroded wiring connection | Check belt condition and tension, inspect wiring and battery terminals, test alternator output |
| Glow plug (preheat) indicator lamp | Preheat circuit active for cold-start assist | Normal cold-start cycle; if lamp fails to light or stay lit, glow plug relay or element fault | Confirm lamp operation before start; if inoperative, check glow plug relay, fuse, and element continuity |
| Air cleaner restriction indicator | Intake air filter restriction beyond allowable limit | Clogged air filter element from dust or debris | Inspect and clean or replace air filter element |
Codes and remedies are general guidance for this model family — always confirm with diagnostic tooling and your dealer before major repairs.
4D95S-1H(S/N 124813-UP) attachments & work tools
Host machine / blade configuration
This engine build (S/N 124813-Up) is factory-fitted to the small Komatsu D20-7A generation crawler tractor line (D20P-7A / D20PG-7A / D20PL-7), not spread across excavators or loaders. Factory push blade on this class runs a straight-to-power-angle moldboard around 2.5-2.6 m (8'4") wide, angling to roughly 2.4 m (8') on the angling builds; blade mounts to the track frame on a C-frame and trunnion arrangement rather than a quick-coupler.
Undercarriage / track shoe options
Standard shoe on this dozer class is a wide single-grouser pad around 510 mm (20 in); a narrower single-grouser shoe near 340 mm (13.5 in) is used where a smaller footprint is needed, trading flotation for higher ground pressure. Double- and triple-grouser pads also appear across the D20 family depending on build; shoe choice is the main undercarriage variable rather than a bolt-on work tool.
Ripper / scarifier
A rear-mounted single-shank ripper or scarifier bar is used on this small-dozer class to break up hard ground behind the blade pass, and a brush-rake attachment shows up in the same class for land-clearing duty. Lift arrangement and factory availability vary by build - verify against your dealer's configuration list for this exact serial range.
ROPS / canopy guarding
Factory overhead protection for this dash-7-era small dozer is a fiberglass sun/rain canopy; steel ROPS/FOPS canopy kits are commonly retrofitted where forestry or brush-clearing work calls for real overhead impact protection.
PTO / flywheel-driven hydraulics
The 4D95S-1H drives the dozer's blade-lift and steering-clutch hydraulic pump straight off the flywheel/flywheel-housing PTO rather than through a separately mounted attachment pump. No external PTO or auxiliary drive option is documented for this engine build.
Aspiration, governor and cooling
This build is naturally aspirated with a mechanical inline fuel-injection pump and all-speed mechanical governor, typical of this pre-electronic engine generation; no turbocharged variant is documented for the 1H/1J S/N 124813-Up range. Cooling uses a standard belt-driven fan and radiator package with no alternate cooling arrangement documented.
All 4D95S-1H(S/N 124813-UP) assemblies by section
Every catalogued assembly group for the Komatsu 4D95S-1H(S/N 124813-UP). Open an assembly to preview the parts inside — full OEM part numbers are available in Heavy Parts AI.
Engine
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Air Cleaner
| 01***16 | Bolt,(With Alternator Cover Type) | 2 |
| 01***06 | Nut | 6 |
| 04***10 | Ring,See Fig. K4010-65a0 | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Air Intake Manifold
| 01***65 | Stud | 1 |
| 01***12 | Bolt,(With Speedometer) | 4 |
| 01***65 | Bolt,(With Water Separator) | 5 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Air Intake Manifold (With Pre-Cleaner)(#162320-)
| 01***65 | Stud | 1 |
| 01***65 | Bolt,(With Water Separator) | 5 |
| 01***75 | Bolt,(For Shipping) | 6 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Air Intake Manifold (With Water Separator)
| 01***75 | Stud | 1 |
| 01***12 | Bolt,(With Speedometer) | 4 |
| 01***65 | Bolt,(With Water Separator) | 4 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Alternator (15a) (Inner Parts)
| 60***50 | Alternator A. (15a) | 1 |
| KD***70 | Cover | 1 |
| KD***30 | Retainer | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Alternator (25a) (Inner Parts)(#163446-)
| 60***20 | Alternator A. (25a),(With Non Hardening Pulley) | 1 |
| KD***57 | Bearing,Ball? Front | 1 |
| KD***11 | Rear Bracket Ass'Y | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Alternator Mounting (15a)
| 01***25 | Bolt,(With Corrosion Resistor) | 1 |
| 01***55 | Bolt,(With Engine Stop Motor Type) | 1 |
| 01***06 | Nut | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Alternator Mounting (25a)(#163446-)
| 01***35 | Bolt | 1 |
| 01***55 | Bolt,(With Engine Stop Motor Type) | 1 |
| 01***11 | Nut,(For Center Guard) | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Block Heater (Cold Terrain Spec.)
| 01***25 | Bolt,(With Corrosion Resistor) | 4 |
| 60***90 | Heater,Water | 1 |
| 62***10 | Gasket,Plate (Except Japan) | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Cable Support(#128722-)
| 01***40 | Bolt,(Shim 3-Piece) | 3 |
| 10***10 | Bracket | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Camshaft And Tappet
| 01***20 | Screw | 2 |
| 04***16 | Fitting Wedge | 1 |
| 62***31 | Thrust Washer | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Cooling Fan
| 01***25 | Bolt,(With Corrosion Resistor) | 4 |
| 01***30 | Bolt,(Water Separator Spec.) | 4 |
| 60***40 | Fan,Cooling | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Crank Pulley
| 01***35 | Bolt | 1 |
| 61***20 | Bolt | 1 |
| 62***40 | Pulley?Non Hardening,Crank (For Trimming Dozer) | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Crankshaft
| 62***00 | Crankshaft Ass'Y | 1 |
| 62***00 | Main Metal Ass'Y | 5 |
| 62***00 | Thrust Metal Ass'Y | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Cylinder Block
| 04***20 | Pin,Dowel (Welded) | 2 |
| 04***28 | Pin, Dowel - Transmission Case, Pin-Dowel | 2 |
| 04***08 | Adapter Sleeves | 6 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Cylinder Block (Cold Terrain Spec.)
| 04***20 | Pin,Dowel (Welded) | 2 |
| 04***28 | Pin, Dowel - Transmission Case, Pin-Dowel | 2 |
| 04***08 | Adapter Sleeves | 6 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Cylinder Block Cover
| 01***14 | Bolt | 2 |
| 61***20 | Gasket,Plate | 1 |
| 62***10 | Plate | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Cylinder Block Cover (Cold Terrain Spec.)
| 01***14 | Bolt | 2 |
| 61***20 | Gasket,Plate | 1 |
| 62***10 | Plate | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Cylinder Block Gasket Kit(#.-)
| 01***12 | Washer,Lock (Noise Suppression Spec.) (K2) | 1 |
| 01***12 | Washer,Lock? Injection Gear | 1 |
| 07***18 | O-Ring,(See Fig.1601-29?1602-17) | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Cylinder Block Gasket Kit(#124813-.)
| 07***65 | O-Ring,Injection Pump Case | 1 |
| 07***95 | O-Ring,Transmission Strainer | 1 |
| 07***35 | O-Ring,Hydraulic Oil Filter | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Cylinder Head
| 01***32 | Washer, (Without Emergency Steering) | 17 |
| 02***04 | Plug, Pipe | 1 |
| 07***10 | Plug, Expansion | 9 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Cylinder Head Gasket Kit(#.-)
| 07***90 | O-Ring,(Dk029369-0020) (K2) | 1 |
| 07***40 | O-Ring,Water Pump Mount | 1 |
| 08***14 | Band,(For Additional Fuel Strainer) | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Cylinder Head Gasket Kit(#124813-.)
| 07***40 | O-Ring,Water Pump Mount | 1 |
| 08***14 | Band,(For Additional Fuel Strainer) | 1 |
| 08***19 | Band,(Without Air Conditioner) | 2 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Engine Mounting(#128722-)
| 01***55 | Bolt, Mount Tube To Switch Pump | 8 |
| 01***45 | Bolt, Bracket Mounting | 5 |
| 01***32 | Washer,(With Auto Emergency Steering) | 8 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Exhaust Manifold
| 01***25 | Grub Screw | 4 |
| 01***45 | Bolt, Bracket Mounting | 7 |
| 61***50 | Nut | 4 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Exhaust Manifold (With Spark Arrester And Catalyzer Type)
| 01***25 | Grub Screw | 4 |
| 01***45 | Bolt, Bracket Mounting | 5 |
| 61***50 | Nut | 4 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Flywheel Housing
| 01***30 | Bolt - Lower Oil Cooler Outlet Tubemounting | 11 |
| 61***32 | Seal? Rear (K2) | 1 |
| 62***70 | Housing,Flywheel | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Flywheel(#128722-)
| 01***30 | Bolt | 6 |
| 06***04 | Bearing,Ball | 1 |
| 62***93 | Gear,Ring | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Front Cover
| 01***10 | Bolt | 1 |
| 01***16 | Bolt | 2 |
| 01***20 | Bolt,(With Tachometer Outlet) | 6 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Front Cover (Without Cover)
| 01***10 | Bolt | 1 |
| 01***16 | Bolt | 2 |
| 01***16 | Screw | 2 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Front Hanger
| 01***20 | Bolt, Hose Clamps (Inlet And Return Line Hoses) | 2 |
| 62***30 | Hanger,Front (W/O Corrosion Resistor) | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Front Power Take Off (For 13a? 25a Alternator)(#136990-)
| 06***07 | Bearing,Roller | 1 |
| 61***60 | Bearing,Ball | 1 |
| 62***00 | Shaft Ass'Y,Power Take Off | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Front Power Take Off (For 15a Alternator)
| 06***07 | Bearing,Roller | 1 |
| 61***60 | Bearing,Ball | 1 |
| 62***60 | Distance Piece | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Fuel Filter(#124813-157192)
| 01***65 | Bolt,(With Water Separator) | 2 |
| 07***12 | Gasket,(Without Air Compressor Type) (K1) | 6 |
| 07***14 | Bolt,Joint | 2 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Fuel Filter(#157193-)
| 01***65 | Bolt,(With Water Separator) | 2 |
| 07***12 | Gasket,(Without Air Compressor Type) (K1) | 6 |
| 07***14 | Bolt,Joint | 2 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Fuel Injection Pump (Feed Pump) (Inner Parts)
| DK***20 | Bolt, Joint | 1 |
| DK***00 | Valve,Check | 2 |
| DK***20 | Pump,Priming | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Fuel Injection Pump (Feed Pump) (Inner Parts) (For Japan) (Noise Suppression Spec. For Ec.)
| DK***20 | Bolt, Joint | 1 |
| DK***00 | Valve,Check | 2 |
| DK***20 | Pump,Priming | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Fuel Injection Pump (Governor) (1/2) (Inner Parts)
| DK***00 | Shim? 2.00mm,(High Altitude Spec.) | 0 |
| DK***00 | Adapter | 1 |
| DK***30 | Governor Ass'Y | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Fuel Injection Pump (Governor) (1/2) (Inner Parts) (For Japan) (Noise Suppression Spec. For Ec.)
| DK***00 | Shim? 2.00mm,(High Altitude Spec.) | 0 |
| DK***00 | Adapter | 1 |
| DK***80 | Nut | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Fuel Injection Pump (Governor) (2/2) (Inner Parts)
| DK***00 | Spring,Governor | 1 |
| DK***20 | Lever | 1 |
| DK***40 | Gasket,Air Compressor | 2 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Fuel Injection Pump (Governor) (2/2) (Inner Parts) (For Japan) (Noise Suppression Spec. For Ec.)
| DK***00 | Spring,Governor | 1 |
| DK***20 | Lever | 1 |
| DK***40 | Gasket,Air Compressor | 2 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Fuel Injection Pump (Pump) (1/2) (Inner Parts)
| 62***60 | Injection Pump Ass'Y | 1 |
| DK***30 | Bearing | 0 |
| DK***20 | Shim, 1.40mm; Was Dk029311-7220, Shim? 1.4mm | 0 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Fuel Injection Pump (Pump) (1/2) (Inner Parts) (For Japan) (Noise Suppression Spec. For Ec.)
| 62***50 | Injection Pump Ass'Y | 1 |
| DK***30 | Bearing | 0 |
| DK***20 | Shim, 1.40mm; Was Dk029311-7220, Shim? 1.4mm | 0 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Fuel Injection Pump (Pump) (2/2) (Inner Parts)
| 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***20 | Plunger Ass'Y | 4 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Fuel Injection Pump (Pump) (2/2) (Inner Parts) (For Japan) (Noise Suppression Spec. For Ec.)
| 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***20 | Plunger Ass'Y | 4 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Fuel Injection Pump Lubricator
| 07***12 | Gasket,(Without Air Compressor Type) (K2) | 2 |
| 07***10 | Screw, Banjo Connector (M10-1.25x20) | 1 |
| 62***30 | Pipe,Oil | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Fuel Injection Pump Mounting
| 01***35 | Grub Screw | 4 |
| 01***12 | Bolt,(See Fig.0501) | 1 |
| 01***16 | Bolt,(With Alternator Cover Type) | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Fuel Injection Pump Mounting (For Japan) (Noise Suppression Spec. For Ec.)
| 01***35 | Grub Screw | 4 |
| 01***12 | Bolt,(See Fig.0501) | 1 |
| 01***16 | Bolt,(With Alternator Cover Type) | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Fuel Injection Pump Piping
| 01***12 | Bolt | 2 |
| 01***25 | Screw | 2 |
| 62***10 | Tube,Injection? No.1 | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Fuel Return(#124813-157192)
| 04***10 | Clip | 2 |
| 07***21 | Tube,Spill | 1 |
| 07***85 | Clip | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Fuel Return(#157193-)
| 04***08 | Clip | 1 |
| 07***00 | Clip | 1 |
| 62***10 | Cover | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Glow Plug
| 60***40 | Glow Plug,Glow | 4 |
| 62***10 | Lead | 3 |
| 62***11 | Wire | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Head Cover
| 01***14 | Screw | 1 |
| 01***25 | Bolt,(With Corrosion Resistor) | 1 |
| 04***50 | Screw | 4 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Head Cover (With Water Separator)
| 01***14 | Screw | 1 |
| 01***25 | Bolt,(With Corrosion Resistor) | 1 |
| 04***50 | Screw | 4 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Heater Signal
| 60***61 | Signal,Heater | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Idler Gear
| 01***70 | Bolt,(For 75a Alternator) | 1 |
| 04***20 | Ring, Snap | 1 |
| 06***06 | Bearing,Roller | 2 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Inhibtor
| 60***20 | Inhibitor | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Injection Nozzle(#124813-157192)
| 01***35 | Bolt, Mount Bracket To Floor | 4 |
| 07***00 | Clip | 8 |
| 62***00 | Nozzle Holder Ass'Y | 4 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Injection Nozzle(#157193-)
| 01***35 | Bolt, Mount Bracket To Floor | 4 |
| 07***00 | Clip | 9 |
| 62***00 | Nozzle Holder Ass'Y | 4 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Muffler
| 01***12 | Bolt,(See Fig.0501) | 2 |
| 01***11 | Nut,(Spark Arrester Spec.) | 2 |
| 07***25 | Hose | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Muffler (For Japan) (Noise Suppression Spec. For Ec.)
| 01***16 | Bolt,(With Alternator Cover Type) | 1 |
| 01***11 | Nut,(Spark Arrester Spec.) | 1 |
| 61***80 | Gasket,Exhaust Manifold | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Muffler (With Spark Arrester)
| 01***16 | Bolt,(With Alternator Cover Type) | 1 |
| 61***80 | Gasket,Exhaust Manifold | 1 |
| 62***10 | Muffler | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Name Plate And Caution (Chinese)
| 09***61 | Plate? Instruction,(Chinese) (Not Shown) | 1 |
| 09***63 | Plate? Instruction,Air Cleaner Element Mainte | 1 |
| 60***20 | Plate? Caution,Oil Filter | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Name Plate And Caution (English)
| 09***61 | Plate? Instruction,Air Cleaner (Single Element) | 1 |
| 09***63 | Plate? Instruction,Air Cleaner (Single Element) | 1 |
| 60***30 | Plate? Caution,Oil Filter And Bypass Filter | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Name Plate And Caution (French)
| 09***62 | Plate? Instruction,Air Cleaner (Double Element) | 1 |
| 09***63 | Plate? Instruction,Air Cleaner Element Mainte | 1 |
| 60***90 | Plate? Caution,(French-English) | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Name Plate And Caution (German)
| 09***61 | Plate? Instruction,(German-English) (Not Shown) | 1 |
| 09***63 | Plate? Instruction,Air Cleaner Element Mainte | 1 |
| 60***80 | Plate? Caution,(German-English) | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Name Plate And Caution (Indonesian)
| 09***61 | Plate? Instruction,(Indonesian-English)(Not Shown | 1 |
| 09***63 | Plate? Instruction,(For Indonesia) | 1 |
| 60***50 | Plate? Caution,(Indonesian-English) | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Name Plate And Caution (Italian)
| 09***61 | Plate? Instruction,(Italian-English) (Not Shown) | 1 |
| 09***63 | Plate? Instruction,(For Italian) | 1 |
| 60***20 | Plate? Caution,(Italian-English) | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Name Plate And Caution (Russian)
| 09***63 | Plate? Instruction,Air Cleaner | 1 |
| 09***62 | Plate? Instruction,Air Cleaner (Double Element) | 1 |
| 60***50 | Plate? Caution,(Russian-English) | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Name Plate And Caution (Spanish)
| 09***61 | Plate? Instruction,(Spanish-English) (Not Shown) | 1 |
| 09***63 | Plate? Instruction,(Spanish) (Not Shown) | 1 |
| 60***70 | Plate? Caution,Oil Filter And Bypass Filter | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Nozzle Holder (Inner Parts)(#124813-157192)
| 62***10 | Holder Ass'Y | 4 |
| DK***00 | Shim? 0.75mm | 0 |
| DK***00 | Shim? 1.200mm | 0 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Nozzle Holder (Inner Parts)(#157193-)
| 62***10 | Holder Ass'Y | 4 |
| DK***00 | Shim? 0.75mm | 0 |
| DK***00 | Shim? 1.200mm | 0 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Oil Filter
| 60***40 | Cartridge,Engine Oil Filter (D31s) | 1 |
| 60***41 | Cartridge,Engine Oil Filter (D31s) | 1 |
| 60***42 | Cartridge,Engine Oil Filter | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Oil Level Gauge (Cold Terrain Spec.)(#124813-163445)
| 01***95 | Bolt,(For Shipping) | 1 |
| 01***20 | Bolt,(For Japan Pc200) | 1 |
| 61***20 | Spacer,(For Shipping) | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Oil Level Gauge (Cold Terrain Spec.)(#163446-)
| 01***95 | Bolt,(For Shipping) | 1 |
| 01***20 | Bolt,(For Japan Pc200) | 1 |
| 61***20 | Spacer,(For Shipping) | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Oil Level Gauge(#124813-163445)
| 01***95 | Bolt,(For Shipping) | 1 |
| 01***20 | Bolt,(For Japan Pc200) | 1 |
| 61***20 | Spacer,(For Shipping) | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Oil Level Gauge(#163446-)
| 01***95 | Bolt,(For Shipping) | 1 |
| 01***20 | Bolt,(For Japan Pc200) | 1 |
| 61***20 | Spacer,(For Shipping) | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Oil Pan And Suction Tube (Cold Terrain Spec.)(#124813-163445)
| 01***16 | Bolt, Mount Solenoid Valve | 24 |
| 01***12 | Bolt,(See Fig.0501) | 1 |
| 01***16 | Screw | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Oil Pan And Suction Tube (Cold Terrain Spec.)(#163446-)
| 01***16 | Bolt, Mount Solenoid Valve | 24 |
| 01***12 | Bolt,(See Fig.0501) | 1 |
| 01***16 | Screw | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Oil Pan And Suction Tube(#124813-163445)
| 01***16 | Bolt, Mount Solenoid Valve | 24 |
| 01***12 | Bolt,(See Fig.0501) | 1 |
| 01***16 | Screw | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Oil Pan And Suction Tube(#163446-)
| 01***16 | Bolt, Mount Solenoid Valve | 24 |
| 01***12 | Bolt,(See Fig.0501) | 1 |
| 01***16 | Screw | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Oil Pressure Switch
| 08***05 | Switch,Engine Oil Pressure | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Oil Pressure Switch (Cold Terrain Spec.)
| 08***05 | Switch,Engine Oil Pressure | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Oil Pump
| 01***16 | Screw | 4 |
| 01***25 | Bolt,(With Corrosion Resistor) | 1 |
| 62***01 | Cover Ass'Y | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Oil Pump (Cold Terrain Spec.)
| 01***16 | Screw | 4 |
| 01***25 | Bolt,(With Corrosion Resistor) | 1 |
| 62***01 | Cover Ass'Y | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Piston
| 04***12 | Ring, Snap | 8 |
| 62***60 | Piston (S) | 4 |
| 62***60 | Piston (S) | 4 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Rear Hanger
| 01***20 | Bolt, Hose Clamps (Inlet And Return Line Hoses) | 2 |
| 62***10 | Hanger,Rear | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Rocker Arm
| 01***65 | Bolt,(For Alternator Bracket Mount) | 5 |
| 61***30 | Circlip | 2 |
| 62***00 | Shaft Ass'Y | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Spare Parts (Cold Terrain Spec.)
| 04***47 | V-Belt,(With 25a Alternator) | 1 |
| 07***16 | Gasket,(For Pc750-6) (See Fig.A2110) | 1 |
| 60***41 | Cartridge,Engine Oil Filter (D31s) | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Spare Parts (For 13a Alternator)
| 04***46 | V-Belt,Cooling Fan | 1 |
| 07***16 | Gasket,(For Pc750-6) (See Fig.A2110) | 1 |
| 60***41 | Cartridge,Engine Oil Filter (D31s) | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Spare Parts (For 25a Alternator)(#163446-)
| 04***48 | V-Belt,(For 50a? 75a Alternator) | 1 |
| 07***16 | Gasket,(For Pc750-6) (See Fig.A2110) | 1 |
| 60***41 | Cartridge,Engine Oil Filter (D31s) | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Spare Parts (Noise Suppression Spec. For Ec.)
| 07***16 | Gasket,(For Pc750-6) (See Fig.A2110) | 1 |
| 60***41 | Cartridge,Engine Oil Filter (D31s) | 1 |
| 62***10 | V-Belt,Fan Drive | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Starting Motor (2.8kw) (Inner Parts)(#124813-157192)
| 60***70 | Starting Motor Ass'Y,(2.8kw) | 1 |
| KD***60 | Bracket,Center | 1 |
| KD***50 | Stopper,Piston | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Starting Motor Mounting (2.8kw)
| 01***30 | Bolt | 2 |
| 07***95 | O-Ring,Transmission Strainer | 1 |
| 60***71 | Starting Motor Ass'Y,(2.8kw) | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Stop Motor
| 01***16 | Bolt, Mounting Transmission Control Switch | 3 |
| 01***25 | Bolt - Relay Mounting | 3 |
| 01***30 | Bolt - Lower Oil Cooler Outlet Tubemounting | 2 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Water Pump
| 01***16 | Screw | 5 |
| 01***25 | Bolt - Relay Mounting | 2 |
| 01***20 | Screw | 2 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Water Pump Pulley
| 04***47 | V-Belt,(With 25a Alternator) | 1 |
| 62***61 | Pulley?Non Hardening | 1 |
| 62***10 | Plate | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Water Pump Pulley (For 25a Alternator)(#163446-)
| 04***48 | V-Belt,(For 50a? 75a Alternator) | 1 |
| 62***60 | Pulley?Non Hardening | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Water Pump Pulley (For Japan) (Noise Suppression Spec. For Ec.)
| 62***10 | V-Belt,Fan Drive | 1 |
| 62***70 | Pulley | 1 |
Komatsu : 4d95s-1h(S/N 124813-Up) : Engine : Water Separator
| 01***25 | Bolt,(With Corrosion Resistor) | 2 |
| 07***60 | O-Ring,(For Pc750?800?1800) (A2610) | 1 |
| 07***12 | Gasket,(Without Air Compressor Type) (K1) | 6 |
Frequently asked questions
What engine powers this machine?
It's powered by the Komatsu 4D95S-1H, a mechanically-governed, naturally aspirated four-cylinder diesel displacing 2.69 L (164.2 cu in) and rated 29.8 kW (40 hp) gross at 2450 rpm. There is no ECM or electronic fuel control; injection and governing are entirely mechanical.
What's the operating weight?
Depending on chassis configuration (D20P-7A, D20PG-7A, or D20PL-7), operating weight runs roughly 3.9 to 4.0 tonnes (about 8,700 to 8,900 lb). Attachments and undercarriage options shift the figure within that range.
What replaced it?
The D20-7A generation carried through Komatsu's -7 series into the late 1990s before giving way to the D20/D21-8 generation around 2000, which added a standard ROPS canopy and further chassis refinement. The engine itself belongs to the long-running 4D95 family, which continued in other Komatsu machines well beyond this dozer's production run.
What 4D95S-1H(S/N 124813-UP) owners discuss
What's the real-world reputation of this engine and dozer's powertrain/hydraulics among owners?
Owners and mechanics describe this small dozer family as mechanically tough and simple to keep running, but underpowered for its frame. The naturally aspirated 29.8 kW (40 hp) mechanical engine needs the throttle run high to move real dirt, and at normal throttle settings it often takes multiple passes to spread a load that a bigger machine would handle in one. On the hydraulic side, blade lift cylinders on machines this age commonly develop drift (the blade settles on its own under load) from worn rod seals and packing rather than pump failure. If the barrel and rod are still straight and unscored, a reseal kit typically restores holding pressure without a full cylinder swap.
What undercarriage wear pattern is typical for this class of small dozer?
Track rollers on this platform start with a wear lip of roughly 9-10 mm (3/8 in); once wear reaches about 19 mm (3/4 in) the flange essentially separates from the roller, so that depth is treated as the practical condemn point. Judge rollers by shape as much as by lip depth: round rollers are fine, cupped or out-of-round ones are worn out and should be replaced. On the front idler and rear sprockets, pointed tooth tips mean the sprocket is past its wear limit, while a flat tip profile usually means it's still serviceable. Track tension is held by a grease-fed tensioning cylinder and needs periodic attention on a machine this age.
What's the cold-start routine on this engine, and what tends to fail over time?
This D20-series engine family starts on a bank of glow plugs wired off a common rail rather than any electronic intake-air management, consistent with a mechanically governed engine that has no ECM. The normal routine is to hold the preheat switch, or watch the heat indicator, for roughly 20-30 seconds before cranking; exact timing and wiring can vary a bit by series and model year. Reported failures center on the heat indicator element burning out or the preheat relay/coil going bad, both of which show up as a hard, extended cold start with no smoke or fuel-related cause. In cold climates, many owners add a block or coolant heater rather than relying on the glow plug system alone.
Any known quirks with the mechanical injection pump and governor on this engine?
Rough running, a stumble under load, or trouble revving cleanly on this engine family is more often traced to one bad injector or nozzle than to a fault in the inline injection pump or governor itself. The standard field check is to crack each injector delivery line one at a time with the engine running: if cracking a line changes nothing, that cylinder's injector is the suspect; if the engine responds or stumbles, that cylinder is contributing normally. Excess exhaust smoke or an rpm surge under load is also commonly traced to a clogged air filter restricting intake rather than to the governor.
What passes for an "electrical" or "sensor" issue on an engine built with no ECM?
Since this is a pre-electronic, mechanically governed engine, reported electrical faults stay basic: the glow plug preheat circuit (a burned-out indicator, a failed relay, or an open plug on the rail), the starter and solenoid, and the charging system. There's no sensor network or onboard diagnostics to reference. A no-start or hard-start complaint on this engine gets worked as a fuel-delivery or compression problem first, and a glow plug, battery, or charging problem second, not chased as an electronics fault.
What steering clutch or final drive quirks should owners expect?
Steering clutches on this dozer chassis use a dry housing rather than a wet clutch pack, and they're known to stick after the machine sits idle for a while — moisture works into the dry housing and the brake-adjuster threads corrode, producing grabby or weak steering to one side. Typical symptoms are a steering lever that has to be pulled back further than normal, or a track that barely turns even with the clutch fully engaged. As a field check, bury the blade and push against resistance: if both tracks spin evenly, the clutches and final drives are considered healthy; if one side won't turn at all, suspect a stripped final-drive gear, an over-tight clutch adjustment, or a broken cross shaft. Because this affects steering and braking control, have your dealer verify any clutch or brake-band adjustment before returning the machine to service.
What should I check before buying a used dozer running this engine?
Confirm the serial number and hour meter match the paperwork. Walk around and check the blade skin for punctures or heavy denting, a sign of pushing another machine or working in rock, and look for leaks at the cylinders, final drives, and under the engine and transmission. Check engine oil and coolant levels before starting, and pull the dipstick to look for a milky texture that would flag an internal coolant leak. On the undercarriage, check idler and sprocket wear, track sag, and whether the rollers are still round rather than cupped. Start the engine cold and note glow-plug preheat time and smoke behavior — a slow or smoky cold start is a quick read on both the fuel system and compression. Finally, bury the blade and push against resistance to confirm both tracks spin evenly under load. Have your dealer verify any undercarriage, final-drive, or hydraulic findings that affect value before you commit to the purchase.
Compiled from owner and technician discussions across the industry — experiences vary by serial range and machine history.
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