Komatsuengine(no series)

Komatsu 3D75-2D(S/N 03044-UP)

Maintenance schedule, common problems & OEM parts breakdown

The Komatsu 3D75-2D (S/N 03044-UP) is a compact, naturally aspirated 3-cylinder mechanical diesel engine of 0.994 L displacement, built on a 75 x 75 mm bore and stroke and rated at roughly 13.9-14.2 kW (18.7-19 hp). It carries no ECM or electronic fault-code system; all governing, timing, and fueling functions are mechanical. This engine was the factory powerplant for the Komatsu PC10-6 mini excavator, produced through roughly 1989-1996, sitting in the compact mini-excavator class. Reported operating-weight figures for the PC10-6 vary between sources, so treat any single number with caution and confirm against your specific serial range before quoting it. The machine offered a digging depth of about 2.31 m and a maximum reach near 4.235 m, with buckets in the 300-900 mm class, a backfill blade, an optional ripper tooth, and an optional hydraulic thumb; work tools pinned directly to the dipper linkage, with no quick-coupler fitted.

Komatsu's small-frame excavator line moved on from the PC10-6/3D75-2D pairing to the PC10-7, which carries the related 3D74E-3A engine, reflecting the same generational push toward tighter fueling control and efficiency seen across Komatsu's small-displacement diesels. Because the 3D75-2D predates that shift, it remains a purely mechanical unit with no electronic diagnostics to fall back on, which is exactly why it still has value in today's used and parts market: its simplicity keeps field repair and troubleshooting inexpensive, and mini excavators from this era continue doing daily work in landscaping, utility, and confined-space digging where their small footprint is an advantage. Buyers sourcing parts for this serial range should verify engine identity carefully, since aggregator listings and general web summaries occasionally attach unverified cross-brand engine claims to this model; nothing beyond the Komatsu-built mechanical diesel identity above should be treated as confirmed.

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 3D75-2D(S/N 03044-UP) specifications

Engine

Model	Komatsu 3D75-2D (S/N 03044-UP), a naturally aspirated 3-cylinder diesel in the Komatsu 3D72-2/3D75-2/3D78-1 engine family
Host machine	Factory-fit engine for the Komatsu PC10-6 mini excavator (1989-1996 production); sibling engines 3D75-1 and 3D75-2C power earlier PC10-2/-3/-5 variants of the same chassis family
Gross power	Approx. 13.9-14.2 kW (18.7-19 HP); one source lists 14 kW at rated speed, dealer listings list 19 HP for this exact S/N range
Displacement	0.994 L (68.7 cu in)
Cylinders	3, inline, water-cooled diesel
Bore x stroke	75 mm x 75 mm (reported for the 3D75-2 series; not separately re-verified for the -2D variant)
Rated/max torque speed	Peak torque reported around 2,600 rpm
Emissions tier	Pre-emissions-regulation era engine (1989-1996 build); no emissions tier published

Weights

Operating weight	Reported figures vary across sources and are not independently confirmed for this serial range — verify with your dealer for this exact machine
Ground pressure	Not documented for this machine — verify with your dealer

Dimensions

Transport length	Approx. 4.24-4.4 m (13'11"-14'5")
Transport width	1.4 m (4'7")
Transport height	Approx. 2.29-2.38 m (7'6"-7'10")
Track/shoe width	250 mm (9.8 in) rubber or steel track
Max digging depth	2.31 m (7'7")
Max horizontal reach	4.235 m (13'11")
Bucket width / capacity	0.28 m bucket, approx. 0.085 m3 (0.11 cu yd) standard bucket

Performance

Travel speed	Approx. 3.6 km/h (2.2 mph) low range up to 4.3 km/h (2.7 mph) high range, per PC10-series data (not independently confirmed for the -6 S/N range)
Bucket digging/tear-out force	Not confirmed for this exact model; a related early PC10-1 variant is documented around 15.3 kN — do not carry that figure over without dealer verification
Gradeability	Not documented for this machine — verify with your dealer

Service capacities (summary)

Fuel tank	Not documented for this exact serial range — verify with your dealer
Hydraulic system	Not documented for this exact serial range — verify with your dealer
Engine oil	Not documented for this exact serial range — verify with your dealer
Cooling system	Not documented for this exact serial range — verify with your dealer

Values vary by configuration, region, and serial range — confirm against your machine before planning transport or lifts.

3D75-2D(S/N 03044-UP) fluids & capacities

System	Capacity	Recommended fluid
Engine crankcase (with filter)	3.9 L (4.1 US qt / 1.0 US gal)	SAE 10W-30, 15W-40, or 5W-30 diesel engine oil meeting API CD/CE service classification, selected by ambient temperature. Equivalent to Komatsu genuine diesel engine oil (EO series) at the matching API class for this engine generation.
Cooling system	Not documented for this exact serial range in available sourcing — verify with your dealer	Ethylene-glycol based antifreeze/coolant, Komatsu genuine coolant (AF-NAC type) or equivalent, mixed per climate for freeze protection.
Fuel system	Not applicable at engine level — fuel tank capacity is set by the host machine (Komatsu PC10 mini-excavator series), not the bare engine	No. 2-D diesel fuel; low-temperature grade in cold climates.
Grease points	Per fitting, as needed	NLGI No. 2 lithium-base multipurpose grease (Komatsu genuine grease, G2-LI type or equivalent).

Capacities are refill values from factory literature — always fill to the dipstick/sight gauge, not the number.

Komatsu 3D75-2D(S/N 03044-UP) maintenance schedule

Service interval	Tasks
Every 10 h	Check engine oil level before first start and top up if below the low mark Drain water and sediment from the fuel strainer/water separator Check coolant level at the radiator and inspect fins for mud or debris buildup Walk around the engine block and fuel lines checking for fresh oil, fuel, or coolant seepage Listen for abnormal exhaust smoke color or knocking at idle before moving off Clean the air cleaner element housing weekly if working in dusty landscaping or utility sites
Every 250 h	Change engine oil and replace the oil filter cartridge (3.9 L / 4.1 US qt fill) Clean or replace the fuel filter element on the mechanical fuel system Check and adjust fan/alternator belt tension, replace if cracked or glazed Inspect and clean the air cleaner element, replace if torn or saturated Check battery electrolyte level and clean/tighten terminal connections Grease all engine-to-chassis mount points and inspect for looseness
Every 500 h	Replace the fuel filter element and bleed the mechanical injection system of air Check and adjust intake/exhaust valve clearances on the naturally aspirated head Inspect fuel injection nozzles for correct spray pattern and leakage Inspect radiator hoses, clamps, and the water pump for cracking or weeping Retorque cylinder head and engine mounting bolts to spec
Every 1,000 h	Check injection pump timing and governor linkage adjustment Perform a cylinder compression check and record readings per cylinder Drain and flush the cooling system, refill with correct antifreeze concentration Clean the crankcase breather and inspect for excess blow-by Inspect starter motor and alternator brushes, clean commutators
Every 2,000 h	Decarbonize the cylinder head and lap intake/exhaust valves as needed Send the injection pump out for full calibration and nozzle recalibration Replace the water pump and thermostat as a preventive set Replace engine mounts and inspect the flywheel housing for alignment Recheck engine-to-chassis alignment and driveline fasteners
Every 4,000 h	Pull the engine for a top-end teardown: inspect cylinder liners, pistons, and rings against the 75x75 mm bore/stroke wear limits Check crankshaft main and rod bearing clearances and regrind or replace as required Replace all core cooling and lubrication seals and gaskets as a rebuild set Inspect the camshaft, followers, and timing gear train for wear Reassemble with new bearings and run a controlled break-in before returning to service

Servicing the 3D75-2D(S/N 03044-UP) beyond the schedule

Predictive Maintenance & Fluid Analysis

With no ECM and no fault codes, scheduled oil and fuel sampling is the only real predictive tool on the 3D75-2D. Pull an oil sample at every 250-hour change from the 3.9 L (4.1 US qt) sump and watch iron and aluminum trends for early cylinder-liner or piston wear on the 75 x 75 mm bore/stroke. Check fuel filter sediment for water contamination and inspect coolant strength visually, since documented coolant capacity is not confirmed for this serial range.

Corrective & Common Repairs

Because work tools pin directly to the dipper with no quick-coupler, most linkage wear on this unit is pin-and-bushing wear rather than coupler wear, so check dipper and bucket pin bores regularly. On the mechanical fuel system, rough idle, hard starting, or excess smoke usually traces to injection pump or nozzle wear rather than an electronic fault, so plan for pump/nozzle service before chasing other causes. Inspect undercarriage rollers and the backfill blade/ripper tooth for wear typical of small-frame digging duty.

Overhaul & Rebuild Points

At major rebuild, focus on the 75 x 75 mm cylinder bore for liner and ring wear, crankshaft main/rod bearing clearances, and valve seat and guide condition on the naturally aspirated head. The mechanical injection pump should be sent out for full recalibration rather than field-adjusted at overhaul. Given the engine's late-1980s to mid-1990s production window, inspect cooling passages for scale buildup and replace the water pump and thermostat as a preventive pair during teardown.

Seasonal & Environment Servicing

For cold-weather starts on this naturally aspirated mechanical diesel, use the correct season-grade engine oil and confirm coolant antifreeze concentration, since there is no glow-plug/ECM-assisted cold start to compensate for thick oil or weak coolant. Check battery cranking capacity before cold snaps. In hot, dusty landscaping or utility work, inspect and clean the air cleaner element more frequently than the standard 250-hour interval and keep radiator fins clear of packed debris to avoid overheating this small-displacement engine.

3D75-2D(S/N 03044-UP) common service parts

Part number	Part	Notes
YM119810-55621	Fuel Filter Ass'Y	Fuel system service	Check fitment →
YM102103-55520	O-Ring,(For Fuel Filter)	Fuel system service	Check fitment →
YM171051-92760	Wrench,Fuel Filter? Water Separator	Fuel system service	Check fitment →
YM121420-01760	O-Ring,Oil Filter	Lubrication service	Check fitment →
YM171301-92750	Wrench,Engine Oil Filter	Lubrication service	Check fitment →

Always confirm against your machine's serial number — cross-check any part in Heavy Parts AI before ordering.

3D75-2D(S/N 03044-UP) fault codes & troubleshooting

Code	Meaning	Likely cause	What to do
Oil pressure warning lamp (red, oil-can symbol)	Engine lubrication pressure has dropped below the switch threshold	Low oil level, worn oil pump, clogged strainer, or failed pressure switch	Stop engine immediately, check oil level and top up, inspect for leaks before restarting
Coolant temperature warning lamp (red, thermometer symbol)	Engine coolant has exceeded normal operating temperature	Low coolant, clogged radiator fins, slipping or broken fan belt, thermostat stuck closed	Idle and let cool, check coolant level once safe, inspect belt and radiator for debris
Charge warning lamp (red, battery symbol)	Alternator is not charging the battery	Broken or slipping fan/alternator belt, failed alternator, loose or corroded wiring	Check belt tension and condition, check wiring connections, test alternator output
Fuel level warning lamp	Fuel level in tank is low	Tank nearly empty	Refuel and check for leaks if the lamp recurs quickly

Codes and remedies are general guidance for this model family — always confirm with diagnostic tooling and your dealer before major repairs.

3D75-2D(S/N 03044-UP) attachments & work tools

Host machine and application

The 3D75-2D (S/N 03044-UP) is a bare industrial diesel engine, not a standalone machine. Parts catalogs and compatibility listings consistently tie this engine to the Komatsu PC10-6 mini excavator; it is the factory power source for that chassis, sharing the wider 3D75 engine family with related PC10-series excavators. Any work-tool compatibility below is therefore inherited from the PC10-6 host, not the engine itself.

Digging buckets

Standard front-end tool for the PC10-6 class is a pin-on digging bucket, offered in a range of widths from roughly 300 to 900 mm (12 to 36 in), in tooth, smooth-edge, skeleton, or root-rake styles. Typical heaped capacity for this micro-excavator class runs in the 0.03-0.09 m3 range depending on width and edge style.

Backfill/dozer blade

A front backfill blade is a common factory or dealer-fit option on this class of mini excavator, used for grading, leveling, and backfilling trenches. It runs off the machine's main hydraulic circuit and does not require a separate auxiliary valve.

Ripper tooth

A single standard-size ripper tooth attachment is available for this excavator class, mounted in place of or alongside the bucket linkage for breaking up hard or compacted ground ahead of digging.

Hydraulic thumb

A hydraulic thumb (grapple-style bucket thumb) is a documented add-on for the PC10-6, either factory-fitted with its own cylinder, bracket, and control valve, or retrofitted using a diverter/Y-valve that splits flow between the blade circuit and the thumb cylinder. Some units left the factory with this circuit already plumbed; others require aftermarket installation.

Auxiliary hydraulics for attachments

Auxiliary hydraulics are not standard across all PC10-6 units; where present (factory or retrofit), they enable use of thumbs and similar single-function tools. System pressure and flow on this excavator class are modest (roughly 18 MPa, low-flow pump), which limits practical attachment use to light-duty tools rather than high-flow tools like breakers or augers; sourcing on breaker/auger fitment for this specific model is thin and unconfirmed.

Coupler and mounting system

Attachments pin directly onto the bucket linkage/dipper arm; no quick-coupler system is documented for this mini excavator class. Komatsu's quick-coupler line is built for larger excavator classes and is not referenced in connection with the PC10-6 or its bare-pin front linkage.

Undercarriage and operator guarding

The host machine runs on a rubber-track undercarriage (approximately 250-300 mm track width depending on source). Operator protection is configuration-dependent: units are seen with either an open canopy or a fully enclosed cab with doors and windows; no additional ROPS/FOPS attachment guarding beyond this canopy/cab choice is documented.

All 3D75-2D(S/N 03044-UP) assemblies by section

Every catalogued assembly group for the Komatsu 3D75-2D(S/N 03044-UP). Open an assembly to preview the parts inside — full OEM part numbers are available in Heavy Parts AI.

Cooling System

Komatsu : 3d75-2d(S/N 03044-Up) : Cooling System : Water Pump And Cooling Fan

YM***02	Bolt Plated	2
YM***20	O-Ring,(Not Shown)	1
YM***50	Packing,Thermostat	1
YM***51	Sensor,Water Temperature	1

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Cylinder Block

Komatsu : 3d75-2d(S/N 03044-Up) : Cylinder Block : Camshaft And Tappet

YM***01	Gear Ass'Y,Camshaft	1
YM***00	Rod,Push	6
YM***50	Bearing, Thrust	1
YM***11	Camshaft	1

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Komatsu : 3d75-2d(S/N 03044-Up) : Cylinder Block : Crankshaft

YM***00	Gear,Crank	1
YM***00	Crankshaft Ass'Y	1
YM***50	Pulley,Crank	1
YM***10	Spring Pin	1

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Komatsu : 3d75-2d(S/N 03044-Up) : Cylinder Block : Cylinder Block

YM***02	Bolt Plated	3
YM***20	Plug,Drain(Without Oil Cooler Type)	1
YM***00	Plug	2
YM***20	Screw	8

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Komatsu : 3d75-2d(S/N 03044-Up) : Cylinder Block : Flywheel And Flywheel Housing

YM***80	Seal? Rear	1
YM***02	Screw	6
YM***02	Screw	2
YM***50	Case,Rear	1

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Komatsu : 3d75-2d(S/N 03044-Up) : Cylinder Block : Gear Case And Front Cover

YM***02	Bolt Plated	2
YM***10	Washer,Seal	5
YM***51	Cap, Lub. Oil Supply	1
YM***52	Bolt	4

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Komatsu : 3d75-2d(S/N 03044-Up) : Cylinder Block : Oil Pan

YM***40	O-Ring,Drain Plug	1
YM***52	Screw	22
YM***30	Housing Assembly., Gear	1
YM***62	Bolt,(For Shipping)	6

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Komatsu : 3d75-2d(S/N 03044-Up) : Cylinder Block : Piston And Connecting Rod

YM***00	Metal,Crank Pin (Std)	1
YM***50	Piston Ring Ass'Y,0.25mm (Os)	3
YM***00	Piston Ass'Y,0.25mm (Os)	3
YM***00	Screw	2

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Cylinder Head

Komatsu : 3d75-2d(S/N 03044-Up) : Cylinder Head : Air Cleaner

YM***41	Buffle	1
YM***70	Seat	1
YM***40	Band Ass'Y	1
YM***00	Element	1

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Komatsu : 3d75-2d(S/N 03044-Up) : Cylinder Head : Air Intake Manifold And Ribbon Heater

YM***01	Heater,Intake Air	1
YM***10	Gasket,Air Intake Manifold	1
YM***52	Screw	4
YM***00	Clamp	2

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Komatsu : 3d75-2d(S/N 03044-Up) : Cylinder Head : Cylinder Head

YM***00	Cylinder Head A	1
YM***80	Retainer, Spring	6
YM***00	Guide,Valve? Exhaust	6
YM***00	Plug	2

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Komatsu : 3d75-2d(S/N 03044-Up) : Cylinder Head : Cylinder Head Cover

YM***20	Cover, Breather	1
YM***51	Cap, Lub. Oil Supply	1
YM***00	Clip,Breather Hose	1
YM***70	Splash-Guard	1

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Komatsu : 3d75-2d(S/N 03044-Up) : Cylinder Head : Exhaust Manifold And Muffler

YM***62	Bolt	2
YM***02	Stud	1
YM***22	Stud	4
YM***10	Gasket,Exhaust Manifold	1

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Komatsu : 3d75-2d(S/N 03044-Up) : Cylinder Head : Rocker Arm

YM***50	Rocker Arm Ass'Y	6
YM***02	Screw	6
YM***80	Spring	3
YM***40	Rocker Shaft	1

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Electrical System

Komatsu : 3d75-2d(S/N 03044-Up) : Electrical System : Alternator

YM***01	Alternator A. (20a)	1
YM***00	Stator Ass'Y	1
YM***10	Bearing,Ball	1
YM***00	Plate Ass'Y	1

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Komatsu : 3d75-2d(S/N 03044-Up) : Electrical System : Alternator And Mounting

YM***30	Plate,Adjust	1
YM***70	Stud	1
YM***02	Nut	1
YM***52	Screw	1

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Komatsu : 3d75-2d(S/N 03044-Up) : Electrical System : Safety Relay And Ribbon Heater Timer

YM***21	Indicator, Charging	1
YM***11	Limiter, Current	1
YM***01	Relay,Safety	1
YM***10	Limiter,Current	1

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Komatsu : 3d75-2d(S/N 03044-Up) : Electrical System : Starting Motor

YM***54	Plate,Center	1
YM***02	Pinion Ass'Y	1
YM***15	Bolt	2
YM***15	Screw	4

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Komatsu : 3d75-2d(S/N 03044-Up) : Electrical System : Starting Motor And Mounting

YM***52	Bolt Plated	2
(Y***0)	Starting Motor Ass'Y,(See Fig.0661)	1

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Fuel System

Komatsu : 3d75-2d(S/N 03044-Up) : Fuel System : Engine Stop Motor

YM***80	Ring,Snap	1
YM***00	Pin,Cotter	1
YM***10	Bracket	1
YM***90	Motor Ass'Y	1

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Komatsu : 3d75-2d(S/N 03044-Up) : Fuel System : Fuel Filter

YM***40	Lever	1
YM***00	O-Ring (Kit)	1
YM***50	Cartridge	1
YM***21	Fuel Filter Ass'Y	1

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Komatsu : 3d75-2d(S/N 03044-Up) : Fuel System : Fuel Injection Pump

YM***70	Retainer, Spring	3
YM***50	Kit, Shim	1
YM***10	Plate? Caution	1
YM***50	Cover,Side	1

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Komatsu : 3d75-2d(S/N 03044-Up) : Fuel System : Fuel Injection Pump And Piping

YM***20	Retainer, Pipe	1
YM***60	O-Ring,Fuel Injection Pump	1
YM***00	Injection Pipe Ass'Y	1
YM***20	Pipe,Injection? No.2	1

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Komatsu : 3d75-2d(S/N 03044-Up) : Fuel System : Fuel Nozzle And Spill Pipe

YM***70	Union	1
YM***20	Spring	1
YM***51	Check Valve Ass'Y,Joint	1
YM***21	Joint	1

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Komatsu : 3d75-2d(S/N 03044-Up) : Fuel System : Governor

YM***01	Weight Assembly., Governor	1
YM***02	Lever Ass'Y,Stop	1
YM***10	Pin,Stop Lever	1
YM***00	O-Ring (Kit)	1

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Lubricating Oil System

Komatsu : 3d75-2d(S/N 03044-Up) : Lubricating Oil System : Lubricating Oil Filter

YM***50	Nut	1
YM***02	Bolt Plated	3
YM***50	Cartridge,Engine	1
YM***00	Valve,Relief	1

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Komatsu : 3d75-2d(S/N 03044-Up) : Lubricating Oil System : Lubricating Oil Pump

YM***00	Pipe,Oil Inlet	1
YM***00	Oil Pump Ass'Y	1
YM***50	Oil Pressure Transmitter	1
YM***40	Gasket,Inlet Pipe	1

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Tool And Kit

Komatsu : 3d75-2d(S/N 03044-Up) : Tool And Kit : Gasket Kit

YM***10	Gasket,Exhaust Manifold	1
YM***10	Gasket,Air Intake Manifold	1
YM***31	Gasket,Head (Kit)	1
YM***20	O-Ring,Cylinder Head Cover Bolt	3

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Komatsu : 3d75-2d(S/N 03044-Up) : Tool And Kit : Tool

YM***60	Wrench,Fuel Filter? Water Separator	1
YM***50	Screw Driver	1
YM***50	Wrench,Engine Oil Filter	1

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3D75-2D(S/N 03044-UP) serial number reference

The engine serial plate for the 3D75-2D sits on the engine block (commonly on the injection-pump side or rocker cover flange) and is the number referenced by S/N 03044-UP; it is separate from the machine PIN plate. On the PC10-6 host machine, the chassis serial is stamped on a plate at the front of the machine, near the boom foot/swing frame, and on this era of mini excavator it reads as a plain multi-digit number rather than a 3-letter alpha prefix, so there is no letter-code prefix to decode.

Prefix	Identifies	Notes
none confirmed	PC10-6 mini excavator host (chassis S/N 20001-UP)	The 3D75-2D S/N 03044-UP engine is factory-paired with the Komatsu PC10-6 mini excavator, chassis S/N 20001-UP, built roughly 1989-1996. PC10-6 chassis serials are documented as plain numeric strings (low-20000s to low-23000s observed across multiple machines), with no 3-character alpha PIN prefix. Earlier PC10-family generations (PC10-3 with the 3D75-1A engine, PC10-5 with the 3D75-2C engine) run their own separate chassis and engine serial series, not sub-ranges of 03044-UP. Confirm exact chassis serial cutoffs with a Komatsu dealer.

Frequently asked questions

What engine powers the Komatsu 3D75-2D (S/N 03044-UP)?

The designation is the engine itself: a naturally aspirated 3-cylinder mechanical diesel of 0.994 L displacement, 75 x 75 mm bore and stroke, rated around 13.9-14.2 kW (18.7-19 hp), with no ECM or electronic fault codes. It was the factory engine fitted to the Komatsu PC10-6 mini excavator.

What is the operating weight of the machine this engine powers?

Reported figures for the PC10-6 vary across sources and are not independently confirmed for this serial range; treat any specific number with caution. It sits in the compact mini-excavator weight class, and the exact figure should be verified with a dealer for this serial range rather than assumed.

What replaced the Komatsu 3D75-2D in Komatsu's lineup?

The PC10-7 mini excavator, the direct successor to the PC10-6, uses the related 3D74E-3A engine in place of the 3D75-2D, continuing Komatsu's small-frame diesel line into its next generation.

What 3D75-2D(S/N 03044-UP) owners discuss

What happens if this excavator runs out of fuel mid-job, and what should get checked afterward?

Running the tank dry is a documented complaint on this machine: it commonly causes persistent white smoke and rough running once refueled, because air gets pulled into the injection system along with the last of the fuel and any sediment sitting in the tank. One owner tracing this problem found sediment in the fuel bowl and no fuel filter installed at all. Beyond refueling and bleeding, check that each injector line seats and seals correctly; a leaking or misaligned injector on one cylinder let air back into the line and brought the smoke back even after a bleed. Re-seating the injectors and bleeding the system in the correct cylinder order cleared it. Have your dealer verify injection timing and injector seating if smoke persists after a proper bleed.

Is the hydraulic pump interchangeable with the next-generation PC10-7?

Owners ask this often enough that the answer clearly is not obvious. The two generations use different hydraulic pump part numbers, and a straight swap between them is not guaranteed without confirming mounting, spline, and displacement match. Treat this machine as its own generation for hydraulic pump sourcing rather than assuming later-generation stock will fit. Have your dealer verify pump compatibility before ordering a replacement or a used substitute.

Is there a spare hydraulic circuit for adding a thumb?

Owners fitting a hydraulic thumb to this excavator generally do not find a free auxiliary circuit built in from the factory. The dozer blade runs on its own separate line, and the common workaround is tapping into the blade circuit rather than splitting time off the boom, arm, or bucket functions. Since the blade and thumb are rarely used at the same time, this keeps digging functions unaffected. It is a shop-built modification, not a factory option, so expect to fabricate mounting and valving yourself.

What wears out on the undercarriage of a machine this size and age?

On these older mini excavators, rubber track wear and roller and idler wear are the recurring items, more so than anything tied to the engine or hydraulics. Because production ran across several years, the track guide-lug pattern is not identical across every serial number, so a track ordered without checking the machine's actual guide style may not seat correctly. Inspect rollers, idlers, and sprocket teeth for uneven wear, and match replacement tracks to the machine's serial range rather than assuming any same-model track fits.

Are there known cold-start or glow plug quirks with this engine?

Small mechanically injected 3-cylinder diesels of this vintage carry a known glow plug quirk: a plug can show voltage at the terminal and still not be heating the cylinder. A resistance check or a direct heat check at each plug is the only reliable test, not just confirming power reaches it. White smoke and a hard cold start centered on one cylinder is the classic symptom of a plug that tests fine electrically but is not actually heating. Have your dealer verify glow plug and controller function if cold starting stays rough after checking the battery and connections.

What causes black smoke under load on an engine like this?

On a mechanically injected engine without a turbocharger, black smoke under load points to a fuel and air mismatch at the injection pump rather than an electronic fault: over-fueling, worn or dirty injectors, incorrect timing, or a restricted air intake are the usual causes. A brief puff of black smoke on a sudden load or throttle change is normal for this style of pump and injector setup; smoke that holds steady under a steady load is not. Have your dealer verify injection pump timing and injector condition before chasing an air intake fix that may not be the real cause.

What should get checked before buying a used example of this machine?

Confirm the fuel system is clean and correctly bled. Fuel starvation and sediment contamination are a documented complaint on this era of machine, so ask whether it has ever been run dry and inspect the fuel bowl and filter setup. Start it cold and watch for white smoke and a rough idle that clears as it warms; that pattern paired with a hard cold start points at glow plugs or an injector seal rather than something structural. Cycle every hydraulic function, including several together, and watch for cylinder drift or a slow arm and boom under load. Walk the undercarriage for uneven track, roller, and idler wear, and confirm the track guide-lug style matches the machine's serial range before assuming an off-the-shelf track will fit. Review whatever maintenance history is available, since these machines are now well over 30 years old and how the fuel system and hydraulics were cared for matters more than raw hour count. Have your dealer verify compression and injection timing before putting the machine into regular work.

Compiled from owner and technician discussions across the industry — experiences vary by serial range and machine history.

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