Komatsuengine(no series)

Komatsu 3D82AE-3D(S/N 00101-UP)

Maintenance schedule, common problems & OEM parts breakdown

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The Komatsu 3D82AE-3D (S/N 00101-up) is not a standalone machine but a small industrial diesel engine, sold to and installed in Komatsu compact equipment - chiefly the PC28UU-2 and PC28UU-2E mini excavators, a 2.7-3.0 tonne class. Built for Komatsu by Yanmar as part of the 68E-88E engine family, it is a naturally aspirated, direct-injection 3-cylinder with 82 x 84mm bore and stroke, 1.330L displacement, and 18.0:1 compression, mechanically governed with no ECU. Output runs 14.6-21.9kW (19.6-29.5hp) depending on governed speed and installation, and dry weight is 112-128kg depending on flywheel-housing and back-plate configuration. This -3D suffix, identified by S/N 00101-up, was the earliest production run, built roughly from the late 1980s into the mid-1990s.

Later production moved to -3E and -3F suffix engines (S/N 04840-up), fitted to the follow-on PC25R-8/PC27R-8 mini-excavator generation, and separately to -3HB/-3HC variants with revised injection-timing calibration for emissions compliance. The core 82 x 84mm block, three-cylinder layout, and direct-injection architecture carried through these updates; the real changes were in injection calibration, timing, and flywheel-housing/back-plate fitment for different host machines, not displacement or output class. Because it predates electronic engine management, the 3D82AE-3D remains a straightforward mechanical rebuild: no fault codes, no sensors, and parts commonality across the 68E-88E family keeps used and rebuilt components available. For owners of surviving PC28UU-2/-2E excavators, this engine is now sourced mainly through the used and rebuilt parts market, which makes correct serial-number identification essential before ordering injection or gasket components across the -3D/-3E/-3F split.

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 3D82AE-3D(S/N 00101-UP) specifications

Engine

Model / configuration	Komatsu 3D82AE-3D, S/N 00101-UP. Member of the 68E-88E series 3-cylinder engine line: vertical, 4-cycle, water-cooled diesel with direct injection (not the swirl pre-combustion type used on some other engines in the same family).
Cylinders, bore x stroke	3 cylinders, 82 mm x 84 mm bore and stroke (3.23 in x 3.31 in).
Displacement	1.330 L (81.2 cu in).
Compression ratio	18.0:1.
Firing order	1-3-2-1.
Gross power	14.6-21.9 kW (19.6-29.5 hp) gross, depending on the fixed governed speed selected for the installation (2,000-3,000 rpm) - varies by configuration. A given machine application is set to one point on this curve, not the full range.
Emissions tier	Not emissions-certified. This base engine predates U.S. EPA/California ARB nonroad certification; later running-change revisions of the same base engine (different suffix letter) were recalibrated to meet EPA standards.

Weights

Dry weight

112 kg (247 lb) engine with back plate; 128 kg (282 lb) engine with flywheel housing - varies by configuration.

Dimensions

Overall envelope, L x W x H	520.5 x 489 x 565 mm (20.5 x 19.3 x 22.2 in) with back plate; 528 x 489 x 565 mm (20.8 x 19.3 x 22.2 in) with flywheel housing - varies by configuration.
Crank / fan pulley diameter	110 mm crank pulley, 110 mm fan pulley (4.3 in each).
Cooling fan	Pusher-type, 335 mm (13.2 in) diameter.

Performance

Governed speed range	Rated speed is fixed between 2,000 and 3,000 rpm depending on application. Max no-load speed tracks the rated point, running 2,180-3,180 rpm (+50/-0 rpm) across that range.
Idle speed	About 800 rpm minimum, no load.
Rotation / power takeoff	Counterclockwise viewed from the flywheel end; power takeoff is at the flywheel.
Governor	Mechanical centrifugal governor, all-speed type.
Starting system	Electric.
Lubrication oil pressure	0.29 +/- 0.05 MPa (3.0 +/- 0.5 kg/cm2) at rated operating speed; about 0.06 MPa (0.6 kg/cm2) at idle.

Service capacities (summary)

Engine oil	5.0 L max / 1.7 L effective (1.3 US gal max / 0.45 US gal effective).
Cooling system	1.8 L (0.5 US gal), engine-side circuit only - total installed system capacity depends on the host machine's radiator and hoses and runs higher.
Fuel tank / hydraulic system	Not applicable at the engine level. This is a bare engine package; fuel tank and any hydraulic circuit are supplied by the host machine.

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

3D82AE-3D(S/N 00101-UP) fluids & capacities

System	Capacity	Recommended fluid
Engine crankcase (with oil filter)	Max 5.0 L / effective (service fill) 1.7 L (1.32 US gal max / 0.45 US gal effective) - effective figure is the amount added at a routine oil-and-filter change; total system volume varies slightly with sump and flywheel-housing configuration	Factory spec calls for engine oil meeting API Service Classification CC or higher. Viscosity is selected by ambient operating temperature: SAE 10W for cold climates down to roughly -20C, SAE 5W-20 or 10W-30 for general/moderate conditions, stepping up to SAE 20W-30 or 20W-40 for hot climates above about 20-30C. The factory chart does not call out a specific brand name, only the API/SAE grade.
Cooling system (engine circuit only)	1.8 L (0.48 US gal) for the engine-side circuit; total system capacity including the radiator, hoses and any sub-tank depends on the host machine's installation and runs higher - varies by configuration	Use clean, low-mineral water with a rust-preventive coolant/antifreeze additive; never fill with hard water. Drain and refill at 400-hour or annual intervals, whichever comes first. Add an antifreeze agent for cold-weather operation per dealer guidance; no specific coolant brand is named in the factory chart.
Fuel system	Not specified at the engine level - the fuel tank is part of the host machine, not the engine package	Diesel fuel oil equivalent to or better than ISO 8217 DMA / BS 2869 Part 1 Class A1 or Part 2 Class A2, minimum Cetane Number 45. Poor fuel quality is called out as a cause of exhaust valve deposits, piston ring groove deposits and injector nozzle clogging.

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

Komatsu 3D82AE-3D(S/N 00101-UP) maintenance schedule

Service interval	Tasks
Every 10 h	Check engine oil level before starting; top up to the correct mark if low. Check coolant level in the radiator/reservoir and inspect hoses and clamps for leaks. Drain water and sediment from the fuel filter/sedimenter. Inspect the air cleaner element and housing for dust buildup or damage. Check fan/alternator belt tension and condition weekly. Listen for abnormal noise and watch exhaust smoke color at startup; act on any oil-pressure, charge, or pre-heat lamp warning immediately.
Every 250 h	Change engine oil and replace the oil filter cartridge. Clean or replace the air cleaner element. Check battery electrolyte level and clean terminals. Inspect all engine hoses and clamps for cracking or looseness. Check and adjust fan belt tension.
Every 500 h	Replace the fuel filter cartridge and bleed the fuel system. Clean radiator and oil cooler fins of dirt and debris. Check intake and exhaust connections for tightness. Inspect glow-plug preheat wiring, connections, and timer relay operation. Check engine mounting bolts and flywheel-housing/coupling fasteners for torque.
Every 1,000 h	Check and adjust valve clearance. Check fuel injection timing and reset if out of specification. Remove, test, and clean injector nozzles; check spray pattern and opening pressure. Check cylinder compression on each cylinder and log the readings. Drain and replace engine coolant; flush the engine-only cooling circuit. Check starter motor and alternator condition and output.
Every 2,000 h	Check cylinder head bolt torque and inspect head gasket condition. Inspect and recondition valve seats and guides as needed. Check crankshaft pulley/vibration damper condition and mounting. Send the injection pump for bench test and recalibration if delivery has drifted. Inspect flywheel housing and drive coupling to the host machine for wear.
Every 4,000 h	Remove and measure cylinder liners, pistons, and rings against factory wear limits. Measure crankshaft journals and bearing clearances; regrind or replace as needed. Inspect camshaft, timing gears, and bushings for wear; replace worn components. Pressure-test and recondition the cylinder head; replace valve guides and seats if worn. Replace the injection pump and injectors as a matched set if calibration keeps drifting between services.

Servicing the 3D82AE-3D(S/N 00101-UP) beyond the schedule

Predictive Maintenance & Fluid Analysis

This mechanically governed engine carries no ECU and sets no fault codes; oil-pressure, charge, and pre-heat lamps plus an audible alarm are the only onboard warnings. That makes scheduled oil sampling the real diagnostic tool. Effective oil volume is only 1.7L (5.0L max), so contamination and wear metals show up fast in analysis. Track exhaust smoke color, cold-start behavior, and compression trend between services to catch injector, nozzle, or ring wear before it costs power, since nothing else on this engine will flag it first.

Corrective & Common Repairs

Hard starting on this engine usually traces to fuel-system air or a sticking fuel shutoff solenoid - bleed the system at the filter and pump before condemning injectors. Cold mornings expose glow-plug preheat timer relay faults; if the pre-heat lamp cycles wrong, check the relay before the plugs. Power loss under load points to injector nozzle or pump wear from accumulated hours. On the host PC28UU-2/-2E, weak digging or swing force is often the hydraulic pump or relief valve, not the engine.

Overhaul & Rebuild Points

At major overhaul, the wear points are the usual mechanical-diesel list: cylinder liner and piston ring wear from accumulated running hours, rod and main bearing clearance, and valve seat/guide condition in the head. Because this is an early -3D suffix engine (S/N 00101-up), confirm flywheel-housing and back-plate configuration before sourcing gasket sets or seals, since later -3E/-3F production changed these to fit different host machines. Injection pump recalibration and nozzle testing belong in any rebuild - drift here erodes power and fuel economy as much as cylinder wear does.

Seasonal & Environment Servicing

Cold starts depend on the glow-plug preheat system since there is no ECU to trim injection timing automatically; watch the pre-heat lamp and switch to a lighter 10W oil in cold ambient per the viscosity chart. Check coolant concentration in the small 1.8L engine-only circuit before winter - little margin for dilution here. In hot, dusty trenching work typical of the PC28UU-2 mini-excavator class, clean the air cleaner element more often than the standard interval and keep the host undercarriage clear of packed debris.

3D82AE-3D(S/N 00101-UP) common service parts

Part number	Part	Notes
YM119833-55620	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 →
YM119810-35300	Intake Oil Filter	Lubrication service	Check fitment →
YM119640-92750	Wrench,Oil Filter? (Pc38uu)	Lubrication service	Check fitment →

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

3D82AE-3D(S/N 00101-UP) attachments & work tools

Work-tool attachments (not applicable)

This is a bare 3-cylinder industrial diesel engine, not a machine with buckets, blades, or quick-couplers. Genuine bucket/blade-type work-tool attachments belong to the host excavator or loader model, not to the engine itself, and none are catalogued against the engine model.

Host-machine / driven-equipment applications

Engines in this displacement and output class (3D82AE-3 series) are factory-fitted as the power unit in compact hydraulic machines of similar size: mini/compact excavators and compact skid-steer or track loaders, plus small wheel loaders. Exact host-model pairing can vary by build calibration within the -3 family, so confirm the specific host machine against its own engine-serial tag rather than assuming from the engine alone.

Flywheel-to-pump coupling (mobile installations)

In excavator and skid-steer installations, the flywheel end couples directly to the machine's main hydraulic pump through a flexible clutch-plate coupling; there is no separate PTO shaft or gearbox in this arrangement. This is the standard drive layout for compact hydraulic machines in this power class.

Flywheel housing / coupling for stationary builds

For pump, compressor, or generator-set installations, the engine is supplied as a short block for the OEM to fit its own flywheel housing and coupling sized to the driven unit, rather than shipping with a catalogued Komatsu PTO kit. Exact flywheel-housing bolt pattern is not published for this specific engine online; confirm with the equipment builder or a Komatsu engine distributor before sourcing a coupling.

Cooling arrangement

Factory cooling is a belt-driven pusher fan paired with an engine-mounted radiator, documented as a standard parts group for this engine. OEM machine builders packaging the engine into enclosed or stationary equipment sometimes substitute a remote-mounted radiator or heat exchanger, but that is an installer choice, not a Komatsu-catalogued factory option for this engine.

Electrical / starting package

Standard factory electrical fitment is a 12V belt-driven alternator and matching 12V starter motor, shared across the related 3D76E/3D82AE/3D84E/3D88E engine family. No factory 24V system or high-output alternator variant is documented for this engine size.

Mounting

No independent chassis, skid, or frame kit is catalogued for the bare engine. It is installed into the host machine's own engine bay using mounting feet and vibration isolators designed by the equipment builder rather than a Komatsu-supplied mounting package.

All 3D82AE-3D(S/N 00101-UP) assemblies by section

Every catalogued assembly group for the Komatsu 3D82AE-3D(S/N 00101-UP). Open an assembly to preview the parts inside — full OEM part numbers are available in Heavy Parts AI.

Cooling System

Komatsu : 3d82ae-3d(S/N 00101-Up) : Cooling System : Water Pump And Cooling Fan

YM***02	Bolt Plated	2
YM***02	Screw	4
YM***20	O-Ring,(Not Shown)	1
YM***11	Gasket (Kit)	1

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Cylinder Block

Komatsu : 3d82ae-3d(S/N 00101-Up) : Cylinder Block : Camshaft And Tappet

YM***01	Gear Ass'Y,Camshaft	1
YM***00	Rod,Push	6
YM***50	Bearing, Thrust	1
YM***62	Bolt,(For Shipping)	2

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Komatsu : 3d82ae-3d(S/N 00101-Up) : Cylinder Block : Crankshaft

YM***00	Gear,Crank	1
YM***80	Parallel Pin	1
YM***50	Pulley,Crank	1
YM***10	Spring Pin	1

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Komatsu : 3d82ae-3d(S/N 00101-Up) : Cylinder Block : Cylinder Block

YM***00	Gauge, Oil Level	1
YM***30	Thrust Metal Ass'Y (Std)	2
YM***20	Plug,Drain(Without Oil Cooler Type)	1
YM***00	Plug	2

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Komatsu : 3d82ae-3d(S/N 00101-Up) : Cylinder Block : Flywheel And Flywheel Housing

YM***50	Oil Seal Case, Assembly	1
YM***80	Seal? Rear	1
YM***02	Screw	6
YM***02	Screw	4

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Komatsu : 3d82ae-3d(S/N 00101-Up) : Cylinder Block : Front Cover

YM***02	Bolt Plated	2
YM***51	Cap, Lub. Oil Supply	1
YM***52	Bolt	4
YM***40	O-Ring,Drain Plug	1

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Komatsu : 3d82ae-3d(S/N 00101-Up) : Cylinder Block : Oil Pan

YM***40	Plug,Drain	1
YM***52	Screw	22
YM***40	Plug,Drain	1
YM***80	O-Ring,Engine Oil Drain	1

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Komatsu : 3d82ae-3d(S/N 00101-Up) : Cylinder Block : Piston And Connecting Rod

YM***00	Connecting Rod, Assembly	3
YM***80	Piston, Assembly	3
YM***00	Screw	2
YM***50	Ring Set (+0.25 mm)	1

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Cylinder Head

Komatsu : 3d82ae-3d(S/N 00101-Up) : Cylinder Head : Air Cleaner And Mounting

YM***41	Buffle	1
YM***10	Support	1
YM***10	Cap	1
YM***30	Pan,Dust	1

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Komatsu : 3d82ae-3d(S/N 00101-Up) : Cylinder Head : Air Intake Manifold And Connection

YM***81	Pipe	1
YM***52	Screw	4
YM***00	Heater,Intake Air	1
YM***10	Gasket,Heater (Kit)	1

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Komatsu : 3d82ae-3d(S/N 00101-Up) : Cylinder Head : Cylinder Head

YM***80	Retainer, Spring	6
YM***00	Guide,Valve? Exhaust	6
YM***00	Plug	2
YM***00	Bolt,Head	14

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Komatsu : 3d82ae-3d(S/N 00101-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 : 3d82ae-3d(S/N 00101-Up) : Cylinder Head : Exhaust Manifold And Muffler

YM***00	Muffler	1
YM***62	Bolt	2
YM***02	Stud	1
YM***22	Stud	4

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Komatsu : 3d82ae-3d(S/N 00101-Up) : Cylinder Head : Rocker Arm

Electrical System

Komatsu : 3d82ae-3d(S/N 00101-Up) : Electrical System : Alternator (40a)

YM***50	Brush Ass'Y	1
YM***00	Retainer,Bearing	1
YM***70	Diode Ass'Y	1
YM***20	Nut Assembly., Pulley	1

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Komatsu : 3d82ae-3d(S/N 00101-Up) : Electrical System : Alternator And Mounting (40a)

YM***02	Nut	1
YM***30	Plate,Adjust	1
YM***10	Spacer	1
YM***50	Bolt	1

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Komatsu : 3d82ae-3d(S/N 00101-Up) : Electrical System : Starting Motor And Mounting

YM***52	Bolt Plated	2
(Y***0)	Starting Motor Ass'Y,(See Fig.A6210-B0a2a)	1
(Y***0)	Starting Motor Ass'Y,(See Fig.A6210-B0a2)	1

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Komatsu : 3d82ae-3d(S/N 00101-Up) : Electrical System : Starting Motor(#00101-09680)

YM***20	Pinion,Pinion	1
YM***80	Catch	1
YM***70	Nut	1
YM***30	Bearing,Ball	1

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Komatsu : 3d82ae-3d(S/N 00101-Up) : Electrical System : Timer? Safety Relay And Glow Relay

YM***20	Timer,Solenoid	1
YM***10	Relay,Stop Solenoid	1
YM***00	Relay, Safety	1
YM***00	Relay, Safety	1

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Fuel System

Komatsu : 3d82ae-3d(S/N 00101-Up) : Fuel System : Fuel Filter And Piping

YM***70	Union	1
YM***40	Lever	1
YM***00	O-Ring (Kit)	1
YM***50	Cartridge	1

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Komatsu : 3d82ae-3d(S/N 00101-Up) : Fuel System : Fuel Injection Pump (Governor) (1/2)

YM***40	Lever,Control	1
YM***30	Spacer,Lever Shaft	1
YM***02	Nut	1
YM***30	Solenoid,Engine Stop	1

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Komatsu : 3d82ae-3d(S/N 00101-Up) : Fuel System : Fuel Injection Pump (Governor) (2/2)

YM***01	Weight Assembly., Governor	1
YM***50	Angleich Ass'Y	1
YM***00	Washer,Spring	1
YM***40	Link? L=30.5,L=30.5 (Mark 05)	1

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Komatsu : 3d82ae-3d(S/N 00101-Up) : Fuel System : Fuel Injection Pump (Pump) (1/2)

YM***50	Kit, Shim	1
YM***10	Plate? Caution	1
YM***50	Cover,Side	1
YM***90	Key,Woodruff	1

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Komatsu : 3d82ae-3d(S/N 00101-Up) : Fuel System : Fuel Injection Pump (Pump) (2/2)

YM***70	Retainer, Spring	3
YM***00	Plunger W/Barrel	3
YM***02	Screw	2
YM***00	Valve,Delivery	3

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Komatsu : 3d82ae-3d(S/N 00101-Up) : Fuel System : Fuel Injection Pump And Piping

YM***20	Retainer, Pipe	1
YM***60	O-Ring,Fuel Injection Pump	1
YM***20	Pipe,Injection? No.2	1
YM***10	Pipe,Injection? No.3	1

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Komatsu : 3d82ae-3d(S/N 00101-Up) : Fuel System : Fuel Nozzle And Spill Pipe

YM***20	Spring	1
YM***00	Fuel Nozzle Ass'Y	3
YM***50	Nozzle, Assembly	1
YM***00	Fuel Injection Nozzle, Assembly	1

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Komatsu : 3d82ae-3d(S/N 00101-Up) : Fuel System : Water Separator

YM***00	Gasket	2
YM***00	O-Ring (Kit)	1
YM***50	Plug,Air	2
YM***10	Bowl, Fuel Strainer	1

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Lubricating Oil System

Komatsu : 3d82ae-3d(S/N 00101-Up) : Lubricating Oil System : Lubricating Oil Filter

YM***50	Nut	1
YM***02	Bolt Plated	3
YM***00	Valve,Relief	1
YM***01	Support	1

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Komatsu : 3d82ae-3d(S/N 00101-Up) : Lubricating Oil System : Lubricating Oil Pump And Piping

YM***50	Oil Pressure Transmitter	1
YM***00	Oil Pump Ass'Y	1
YM***02	Seal,Ring (Kit)	2
YM***41	Gasket (Kit)	1

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Tool And Kit

Komatsu : 3d82ae-3d(S/N 00101-Up) : Tool And Kit : Gasket Kit

YM***60	O-Ring,Fuel Injection Pump	1
YM***00	Gasket Kit	1
YM***40	O-Ring,Drain Plug	1
YM***50	Gasket,(Square Type)	1

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Komatsu : 3d82ae-3d(S/N 00101-Up) : Tool And Kit : Tool

YM***60	Wrench,Fuel Filter? Water Separator	1
YM***50	Screw Driver	1
YM***20	Flex Horn (Option.)	1
YM***50	Wrench,Oil Filter? (Pc38uu)	1

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3D82AE-3D(S/N 00101-UP) serial number reference

On this engine, the ID plate is riveted to the cylinder block, typically on the injection-pump side or near the valve cover; on the host PC28UU-2/PC28UU-2E excavator, the machine PIN/serial plate sits on the frame or under the operator's seat area. Read the engine plate as model (3D82AE-3D) followed by a plain serial number — this engine class does not use a 3-character alpha prefix like larger Komatsu machines, so match the plate digits directly against the 'S/N 00101-UP' heading in the parts or shop manual rather than decoding a letter code. Note the engine serial run is independent of the machine's own PIN/serial number, so do not substitute one for the other when ordering parts.

Prefix	Identifies	Notes
N/A	3D82AE-3D (S/N 00101-UP) base engine run — no 3-character alpha PIN prefix documented	Fitted to the Komatsu PC28UU-2 / PC28UU-2E mini excavator, an approximately 2.7 t (6,000 lb) class machine with a two-piece offset boom and zero-tail-swing design, produced from the late 1980s into the mid-1990s. This is the engine's own factory serial run, separate from the machine's own PIN/serial series. Komatsu-badged, Yanmar-built engines of this class do not carry a 3-letter alpha code ahead of the serial digits in parts and shop-manual listings; plain sequential digits (00101 and up) mark this production block. Later production of the same PC28UU-2 chassis switched to a different engine, so the 3D82AE-3D covers an early portion of that machine's build run, not its entire life. This -3D suffix is distinct from the later -3E and -3F revisions of the same base engine, which start at a higher serial break and pair with different host chassis (PC25R-8 and PC27R-8 respectively) — those are separate engine entries, not part of this -3D run.
N/A	3D82AE-3D fitment on a 'PC28UD-2' excavator — thin, aftermarket-only, unconfirmed by any primary source	More than one aftermarket overhaul-kit or component-compatibility listing pairs this engine suffix with a machine cataloged as 'PC28UD-2' (sometimes alongside a further 'PC28UG-2' designation), in addition to PC28UU-2. No Komatsu-side model listing or independent spec sheet confirms a PC28UD-2 (or PC28UG-2) designation as a distinct factory model; these may be aftermarket-catalog variants or misprints of the PC28UU-2 family rather than distinct models. Confirm exact machine model and serial break with a Komatsu dealer before ordering parts against this host.

Frequently asked questions

What engine is the Komatsu 3D82AE-3D (S/N 00101-up)?

It is a naturally aspirated, direct-injection 3-cylinder diesel with 82 x 84mm bore and stroke, 1.330L displacement, and 18.0:1 compression ratio. It is mechanically governed with no ECU, rated 14.6-21.9kW (19.6-29.5hp) depending on governed speed and installation. Built by Yanmar for Komatsu as part of the 68E-88E engine family, this -3D suffix (S/N 00101-up) was factory-fitted mainly to the Komatsu PC28UU-2/PC28UU-2E mini excavator.

What is the operating weight of the 3D82AE-3D?

As a bare engine rather than a complete machine, dry weight runs 112-128kg (247-282 lb) depending on flywheel-housing and back-plate configuration. This excludes the host excavator's own operating weight - the PC28UU-2/PC28UU-2E it typically powered carries its own separate machine weight rating.

What replaced the Komatsu 3D82AE-3D?

It was superseded by -3E and -3F suffix engines (S/N 04840-up), used in the later PC25R-8/PC27R-8 mini-excavator generation, and separately by -3HB/-3HC suffix engines with revised injection timing for emissions compliance. The core block and displacement carried forward; the changes were in calibration and host-machine fitment.

What 3D82AE-3D(S/N 00101-UP) owners discuss

The mini excavator won't start after sitting for a while or after a fuel filter change - what's the usual cause?

Air in the fuel system, not the engine itself. This engine has no electronic controls, so a no-start after service is almost always mechanical fuel delivery, not a sensor. Crack the fittings at the injection pump inlet and at the injector lines and crank (or run the electric lift pump on key-on) until fuel runs clear with no bubbles, working from the tank forward. If the machine needs constant re-bleeding, suspect an air leak on the suction side between the tank and the lift pump rather than a bad injection pump. Also check the fuel shutoff solenoid on the injection pump body (small 2-3 wire connector) - a sticking or corroded solenoid will block fuel into the pump even with a fully charged battery and normal cranking speed.

Does this engine need a glow-plug preheat cycle, and is it safe to use starting fluid?

Yes. It runs an intake air heater/glow-plug circuit on a timer relay, not an ECU-controlled system. Cycle the preheat and let the wait indicator finish (typically a 15-30 second glow cycle depending on temperature) before cranking; a weak battery or tired starter will make cold starts worse even with good glow plug function. Owners caution against spraying ether or starting fluid into the intake while the glow system is energized or still hot - on a small naturally aspirated diesel like this, igniting starting fluid against a hot glow element can flash back through the intake. If the machine only starts with starting fluid every time, treat that as a fuel-delivery or glow-circuit fault to chase down, not a routine starting method. Have your dealer verify the glow-plug timer relay and preheat circuit before relying on starting fluid as a workaround.

The engine idles fine but loses power or sputters as throttle or load increases - what should be checked?

This points to fuel delivery under demand rather than a governor or electronic fault, since the injection pump is purely mechanical. Typical causes reported are worn injector nozzles giving poor spray pattern, a tired injection pump losing output at higher plunger speeds, or a fuel filter/lift pump too weak to keep up once demand rises. Check the air intake hose and clamps between the air filter and inlet manifold too - a split or loose hose on this small three-cylinder block can starve it of air under load and mimic a fuel problem. A compression check is worthwhile if power loss persists after fuel-side items are ruled out.

All the boom, arm, and bucket functions feel weak or slow, but the engine and travel are fine - what's the usual culprit?

These compact excavators typically run two to three fixed-displacement gear pumps rather than a single load-sensing pump, so a weak feel across the work functions while travel/swing stay normal usually traces to the main relief valve or a clogged suction strainer, not the whole hydraulic pump. Owners troubleshooting this on similar-era Komatsu minis have found pump outlet pressure well under the manual's spec figure, pointing to pump wear; others found a bypassing relief valve was the real cause after the pump tested fine. Pressure-test at the pump outlet with a gauge kit before condemning or swapping the pump.

What undercarriage wear is typical on a machine this age with this engine?

On rubber-tracked versions, expect tread wear, cracking, and lug loss as the track ages, plus tension loss if the track adjuster grease valve leaks down - check and regrease the tensioner before assuming the tracks themselves are shot. Roller and idler wear is common after years of use, along with sprocket tooth wear on steel-track configurations. Loose-feeling tracks on an otherwise sound undercarriage are frequently a tensioning issue rather than worn components.

What electrical issues actually show up on this engine, since it has no engine control module?

Electrical faults are limited to the basic charging and cranking circuit rather than sensors or fault codes - there's no ECM to throw a code. Common items are a weak or discharged battery, a worn starter motor or solenoid causing slow or no crank, corroded ground straps, and failure of the glow-plug preheat timer relay itself (engine cranks normally but is hard to start cold). Diagnosis is straightforward multimeter/test-light work on battery voltage, starter draw, and the glow circuit rather than any diagnostic-code process.

What should be checked before buying a used machine with this engine?

Confirm the engine plate suffix matches the machine's era before assuming parts or injection pump calibration carry over - this earlier "-3D" engine (serial prefix in the 00101-up range) belongs to the first-generation compact excavators of this size class, while later "-3E"/"-3F" suffix engines went into the following generation of machines and are not automatically interchangeable. Beyond that, run a compression or at least a smoke check, confirm oil is clean with no fuel or coolant mixing, and see whether the machine starts on its own without a starting-fluid crutch. Pressure-test the hydraulic pump output and cycle every function at idle and full rpm to check for weak or slow movement. Walk the undercarriage for track, roller, idler, and sprocket wear and check track tensioner grease valves. Check boom, arm, and bucket pins and bushings for play, and check swing bearing/gear play. Ask for maintenance records - these are simple mechanical engines, so a documented service history is a stronger reliability signal than machine hours alone.

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

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