Komatsuengine(no series)
Komatsu SAA6D125E-2D-8(S/N 60721-UP)
Maintenance schedule, common problems & OEM parts breakdown
The Komatsu SAA6D125E-2D-8 engine (S/N 60721-UP) is a turbocharged, aftercooled inline-six diesel belonging to the 125-series family, primarily fitted to the PC600-6A-KJ and PC600-6A-W1 crawler excavators. This mid-to-heavy class machine operates in the 52,300-80,000 lb weight range, serving mass excavation and mining applications. The engine succeeded the naturally aspirated 6D125E-2A and preceded the electronically controlled SAA6D125E-3 and -5 generations. Configurations included standard-gauge E/EX straight-tilt-blade dozer variants and wide-gauge, low-ground-pressure P/PX swamp configurations, sharing the same 11.04 L displacement block across the platform.
Across the 125-series lineage, the primary shift was from mechanical fuel systems and flyweight governors in the 6D125E-2A to the electronically managed, turbo-aftercooled designs of the SAA6D125E-3 and -5. The SAA6D125E-2D-8 remains significant in the used and parts market because its mechanical simplicity allows for straightforward diagnosis and overhaul without reliance on complex ECMs or wiring harnesses. Its robust block design and shared drivetrain lineage with contemporary Komatsu excavators keep parts and service support active, making it a cost-effective rebuild candidate compared to later electronic engines.
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 SAA6D125E-2D-8(S/N 60721-UP) specifications
Engine
| Model | SAA6D125E-2D-8 |
| Series/Generation | 125 Series |
| Cylinders | 6 |
| Displacement | 11.04 L (674 in³) |
| Bore x Stroke | 114 mm x 144.5 mm (4.49 in x 5.69 in) |
| Aspiration | Variable geometry turbocharged, air-to-air aftercooled |
| Cooling | Water-cooled |
| Emissions Tier | Tier 4 Final / EU Stage V (varies by configuration/series) |
Weights
| Operating Weight | 29,300 - 31,688 kg (64,596 - 69,860 lb) (varies by configuration/series) |
| Shipping Weight | Not documented for this exact serial range — verify with your dealer |
| Ground Pressure | Not documented for this exact serial range — verify with your dealer |
Dimensions
| Transport Length | Not documented for this exact serial range — verify with your dealer |
| Transport Width | Not documented for this exact serial range — verify with your dealer |
| Transport Height | Not documented for this exact serial range — verify with your dealer |
| Track Gauge | Not documented for this exact serial range — verify with your dealer |
| Ground Clearance | Not documented for this exact serial range — verify with your dealer |
Performance
| Travel Speed | Not documented for this exact serial range — verify with your dealer |
| Dig Depth | Not documented for this exact serial range — verify with your dealer |
| Bucket Capacity | 5.9 - 14.1 m³ (7.7 - 18.4 cu yd) (varies by configuration/series) |
| Gradeability | Not documented for this exact serial range — 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.
SAA6D125E-2D-8(S/N 60721-UP) fluids & capacities
| System | Capacity | Recommended fluid |
|---|---|---|
| Engine crankcase (with filter) | 38 L (10.0 US gal) | Komatsu Genuine diesel engine oil, EO10W30 or EO15W40 grade selected by ambient air temperature at startup per the OMM viscosity chart (roughly -30 deg C to +50 deg C range, 10W30 for colder end, 15W40 for warmer end); meets Komatsu EO engine-oil classification comparable to API CD/CF-4 duty. |
| Cooling system | 52 L (13.7 US gal) | Komatsu Genuine Supercoolant / Antifreeze Coolant AF-NAC, ethylene-glycol based, factory pre-mixed to a 50/50 ratio; change interval per OMM is 2 years or 4,000 hours, whichever comes first. |
| Fuel tank | 406 L (107.3 US gal) | Not specified in source text. |
| Transmission/powertrain compartments | Not specified in source text. | Not specified in source text. |
| Final drives (each) | Not specified in source text. | Not specified in source text. |
| Hydraulic system AND tank | 55 L (14.5 US gal) | Not specified in source text. |
| Axles/differentials | Not specified in source text. | Not specified in source text. |
| Grease | Not applicable. | Not specified in source text. |
Capacities are refill values from factory literature — always fill to the dipstick/sight gauge, not the number.
Komatsu SAA6D125E-2D-8(S/N 60721-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 SAA6D125E-2D-8(S/N 60721-UP) beyond the schedule
Predictive Maintenance & Fluid Analysis
Pull engine oil and coolant samples on schedule rather than by feel. This 125-series turbo block has a known weep point between coolant and oil circuits, so cross-contamination shows up in lab analysis before it shows on a dipstick. Watch torque converter temperature under load; a slow climb with no external leak points to an internal forward-clutch bypass, not a cooling-system fault. Track undercarriage wear (bushing, sprocket segment, shoe height) against OEM minimums each service interval, since undercarriage cost typically outpaces engine cost over the machine's life.
Corrective & Common Repairs
Oil showing up in coolant on this block usually traces to the oil cooler core, not a cracked head; pressure-test before committing to a gasket job. Torque converter overheating without an external leak is commonly a forward-clutch internal seal letting oil bypass the cooler, not a radiator fault. Weeping around the belly pan is typically a steering clutch or brake seal, hydraulic line, or pump gasket, not the engine itself. Dash and gauge dropouts trace to blown fuses, corroded connectors, or weak grounds behind the panel, not a failed sensor.
Overhaul & Rebuild Points
This turbocharged 125-series block is mechanically governed with no electronic controls, making it a straightforward rebuild candidate compared to later electronic engines. Resurface the head if a coolant weep has been running long enough to erode the surface; check the block for warpage after any overheating event. Match piston rings and liners to factory spec; mismatched aftermarket sets are a common cause of wear inside months, not years. On the undercarriage, segment-style sprockets let a shop renew worn tooth sections without pulling the whole final drive.
Seasonal & Environment Servicing
Select engine oil viscosity by ambient startup temperature per the OMM chart; run the lighter grade through cold snaps and the heavier grade once temperatures climb. Confirm the intake air heater and preheat lamp work before winter; a mechanically governed engine with no electronic cold-start assist depends on that circuit for starts. Keep coolant at the factory antifreeze concentration for freeze protection, not just topped with water. In hot, dusty conditions, clean radiator fins often and check track tension more frequently, since heat and abrasive ground both accelerate undercarriage wear.
SAA6D125E-2D-8(S/N 60721-UP) common service parts
| Part number | Part | Notes | |
|---|---|---|---|
| 07281-00197 | Clamp,(With Pre-Fuel Filter) | Fuel system service | Check fitment → |
| 600-311-8293 | Cartridge, Fuel Filter | Fuel system service | Check fitment → |
| 6114-71-6202 | Fuel Filter Ass'Y | Fuel system service | Check fitment → |
| 6114-71-6210 | Head, Fuel Filter | Fuel system service | Check fitment → |
| 6125-81-7032 | Element Ass'Y,Air Cleaner | Air intake service | Check fitment → |
Always confirm against your machine's serial number — cross-check any part in Heavy Parts AI before ordering.
SAA6D125E-2D-8(S/N 60721-UP) fault codes & troubleshooting
| Code | Meaning | Likely cause | What to do |
|---|---|---|---|
| CA115 | Engine crankshaft speed sensor and backup speed sensor failure | Faulty crankshaft speed sensor, damaged wiring harness, or corroded connector at the sensor pin | Inspect the sensor wiring and connector for corrosion or damage; verify voltage at the pin connector; replace the speed sensor if faulty |
| CA451 | Common rail pressure sensor feedback value too high | Malfunctioning rail pressure sensor, actual overpressure condition, or sensor wiring issue | Diagnose the fuel rail pressure sensor circuit; check for actual overpressure; replace sensor if defective |
| CA122 | Intake air pressure sensor feedback voltage too high | Faulty intake pressure sensor, shorted wiring, or sensor calibration error | Verify the intake pressure sensor operation and wiring integrity; check for airflow restrictions |
| CA123 | Intake air pressure sensor feedback voltage too low | Sensor short circuit, open circuit, or significant airflow restriction upstream | Check for a sensor short or open circuit; inspect for airflow restrictions in the intake system |
| CA441 | Battery voltage too low | Weak or discharged battery, faulty alternator, or loose charging connections | Replace the battery or alternator; check the voltage regulator and charging belt tension |
| CA442 | Battery voltage too high | Faulty voltage regulator, failing alternator, or open ground connection | Replace the alternator or battery; check the voltage regulator and ground connections |
| CA234 | Engine overspeed | Throttle calibration error, engine load cycle anomaly, or operator misuse | Verify throttle calibration; inspect the engine load cycle and operator controls |
| CA271 | IMV/PCV1 solenoid valve short circuit | Electrical short in the IMV or PCV1 solenoid valve circuit | Inspect the solenoid valve wiring for chafing or shorting; replace the IMV solenoid if defective |
| CA322 | Injector #1 (L#1) open or short circuit fault | Open or shorted circuit in the injector #1 wiring harness or connector | Inspect the injector #1 wiring harness and connector for damage; test injector resistance |
| CA111 | Internal engine controller fault | Critical internal failure of the Electronic Control Module (ECM) | Replace or reprogram the ECM; verify power and ground connections to the controller |
Codes and remedies are general guidance for this model family — always confirm with diagnostic tooling and your dealer before major repairs.
SAA6D125E-2D-8(S/N 60721-UP) attachments & work tools
Bulldozer Attachments
The Komatsu D85 series utilizes the SAA6D125E engine family and is equipped with a blade capacity ranging from 5.9 to 7.0 cubic meters (6.1 to 7.3 cubic yards). Operating weight for this configuration is listed between 29,300 and 31,000 kg (64,600 to 68,300 lbs). The engine specification for the D85 includes a bore of 4.49 inches (114 mm) and a stroke of 5.69 inches (144.5 mm), with a total piston displacement of 674 cubic inches (11.0 liters).
Excavator Engine Applications
The SAA6D125E-3 engine variant is explicitly identified for use in the Komatsu PC450-7 crawler excavator, delivering an installed power of 257 kW (345 hp) at 1,900 rpm. The PC450-7 references a specific damper part number 207-01-61311 associated with this engine application. Other models in the 125-series engine family include the PC400-8 and PC450-8, which utilize the SAA6D125E-5 variant.
Wheel Loader Engine Applications
The WA470-5H and WA480-5 wheel loaders are equipped with the SA6D125E-3B-7 or SA6D125E-3B-8 engine variants for serial numbers starting from 50,051. These engines are turbocharged and air-to-air aftercooled, consistent with the SAA6D125E-3 family specifications found in the WA700-8 series.
Engine Specifications & Dimensions
The 125-series engine block features a displacement of 11 liters (674 cubic inches) with six cylinders. The bore and stroke dimensions are 4.49 inches (114 mm) by 5.69 inches (144.5 mm). The engine is water-cooled and operates on a four-stroke cycle, with physical dimensions listed as 1,053 mm by 758 mm by 1,032 mm (41.5 in by 29.8 in by 40.6 in).
All SAA6D125E-2D-8(S/N 60721-UP) assemblies by section
Every catalogued assembly group for the Komatsu SAA6D125E-2D-8(S/N 60721-UP). Open an assembly to preview the parts inside — full OEM part numbers are available in Heavy Parts AI.
Engine
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : After Cooler (Ordering Transferdrd Parts)(#210001-)
| 61***90 | Clamp, Hose | 8 |
| 61***10 | Hose | 1 |
| 61***20 | Tube | 1 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Air Cleaner
| 01***60 | Capscrew | 2 |
| 01***25 | Bolt,(For Canvas Canopy?Head Guard) | 2 |
| 01***35 | Bolt,(F4320-52a0 -5 ) | 2 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Air Intke Manifold(#210001-)
| 01***25 | Bolt,(For Canvas Canopy?Head Guard) | 2 |
| 01***30 | Bolt,(With Body Positioner) | 16 |
| 01***70 | Bolt - Bracket And Oil Inlet Tubemounting | 5 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Air Vent(#75526-)
| 07***12 | Gasket,(Without Air Compressor Type) (K2) | 12 |
| 07***10 | Screw, Banjo Connector (M10-1.25x20) | 6 |
| 61***60 | Tube,Air Vent | 1 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Alternator (35a) (With Non Hardening Pulley) (Inner Parts)
| 60***50 | Alternator A. (35a) | 1 |
| 60***51 | Alternator A. (35a) | 1 |
| KD***50 | Bracket,Rear | 1 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Alternator (50a) (With Non Hadening Pulley) (Inner Parts)(#63014-)
| 60***80 | Alternator A. (50a),(With Non Hardening Pulley) | 1 |
| SD***X0 | Pulley,Non Hardening | 1 |
| SD***X0 | Washer | 1 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Alternator Mounting (35a) (With Non Hadening Pulley)
| 01***65 | Bolt - Return Line And Suction Linehose Clamps | 2 |
| 01***55 | Bolt - Mount Cage To Transmission Case | 1 |
| 01***55 | Bolt | 1 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Alternator Mounting (50a) (With Non Hadening Pulley)(#63014-)
| 01***65 | Bolt - Return Line And Suction Linehose Clamps | 2 |
| 01***55 | Bolt - Mount Cage To Transmission Case | 1 |
| 01***55 | Screw | 1 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Camfollower Cover
| 07***20 | Clamp, Spring Hose | 1 |
| 07***85 | Hose | 1 |
| 61***90 | O-Ring,Breather | 1 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Camshaft(#210001-)
| 01***22 | Capscrew | 2 |
| 04***25 | Key, Plain Woodruff | 1 |
| 04***12 | Ring,Snap (For Ripper) | 12 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Cooling Fan(#210001-)
| 01***30 | Bolt,(With Body Positioner) | 12 |
| 60***70 | Fan,Cooling | 1 |
| 61***70 | Spacer | 1 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Corrosion Resistor(#210001-)
| 01***16 | Bolt, Battery To Frame Ground Wire Attaching | 1 |
| 01***80 | Bolt,(With Corrosion Resistor) | 1 |
| 02***25 | Bolt,(Cold Weather Spec.) | 4 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Crank Pulley
| 01***30 | Screw | 1 |
| 01***35 | Screw | 5 |
| 04***28 | Pin, Dowel - Transmission Case, Pin-Dowel | 1 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Crankshaft
| 61***10 | Bearing, Main (Standard) | 7 |
| 61***50 | Bearing, Thrust Assembly (Standard) | 1 |
| 61***10 | Bearing, Main (1.00mm Undersize) | 7 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Cylinder Block Blind Cover And Plug(#210001-)
| 01***20 | Bolt,(For Mono Lever Steering) | 6 |
| 01***25 | Bolt,(For Canvas Canopy?Head Guard) | 4 |
| 01***85 | Bolt, Divider Valve Mounting | 2 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Cylinder Block Gasket Kit(#210001-)
| 07***20 | O-Ring,Relief Valve | 1 |
| 07***21 | O-Ring,Water Piping | 1 |
| 07***30 | Ring, Seal - Between Sections | 1 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Cylinder Block(#75758-)
| 01***12 | Bolt,(Without Air Compressor Type) | 2 |
| 01***20 | Bolt,(For Shipping) | 1 |
| 01***16 | Bolt, Mount Solenoid Valve | 6 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Cylinder Head Gasket Kit(#210001-)
| 07***65 | O-Ring,Cylinder Block | 6 |
| 07***12 | Gasket,Mechanical Pump Piping | 12 |
| 07***12 | Gasket,(Without Air Compressor Type) (K2) | 12 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Cylinder Head(#67604-)
| 01***20 | Bolt (M10-1.75x120) | 6 |
| 04***20 | Pin,Dowel (Welded) | 2 |
| 07***08 | Plug,(Without Lock-Up), Plug | 1 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Damper
| 01***25 | Bolt,(Without Rops Guard? Canopy) | 6 |
| 61***00 | Damper Assembly | 1 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Electrical Wiring(#210001-)
| 01***10 | Bolt,(With Auto Emergency Steering) | 2 |
| 01***16 | Bolt, Battery To Frame Ground Wire Attaching | 2 |
| 01***20 | Bolt,(For Mono Lever Steering) | 1 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Exhaust Manifold
| 01***00 | Bolt (M10-1.50x100) | 16 |
| 01***80 | Bolt | 2 |
| 01***00 | Screw | 16 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Fan Drive (Pulley Dia 212mm)(#73270-)
| 01***30 | Bolt,(With Body Positioner) | 4 |
| 01***15 | Bolt, Fan Mounting | 6 |
| 01***14 | Nut,(For Slag Handling) | 1 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Fan Pulley (Pulley Dia 212mm)(#73270-)
| 01***30 | Bolt,(With Body Positioner) | 6 |
| 04***62 | V-Belt Set,(For 35a? 50a Alternator) | 1 |
| 61***10 | Pulley?Non Hardening | 1 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Flywheel Housing
| 01***50 | Capscrew | 6 |
| 01***60 | Capscrew | 2 |
| 01***50 | Bolt,(Spark Arrester Spec.) | 2 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Flywheel(#210001-)
| 01***55 | Bolt | 6 |
| 01***45 | Washer,(For Travel Motor) (Not Show) | 6 |
| 61***51 | Gear, Ring | 1 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Front Cover Mounting(#75758-)
| 01***65 | Bolt - Return Line And Suction Linehose Clamps | 7 |
| 01***70 | Bolt - Bracket And Oil Inlet Tubemounting | 4 |
| 01***75 | Bolt (M10-1.50x75) | 5 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Front Cover(#75758-)
| 09***50 | Liquid Gasket, Lg-7, 150g | 0 |
| 61***30 | Seal? Front (K2) | 1 |
| 61***40 | Cover, Front | 1 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Fuel Filter(#210001-)
| 01***25 | Bolt,(For Canvas Canopy?Head Guard) | 3 |
| 01***30 | Bolt,(With Body Positioner) | 1 |
| 01***50 | Bolt,(Spark Arrester Spec.) | 1 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Fuel Injection Pump (Coupling) (Inner Parts)(#210001-)
| DK***00 | Nut | 2 |
| DK***00 | Bolt | 2 |
| DK***20 | Coupling Ass'Y | 1 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Fuel Injection Pump (Feed Pump) (Inner Parts)(#210001-)
| DK***20 | Bolt, Joint | 1 |
| DK***00 | Valve,Check | 2 |
| DK***30 | Feed Pump Assembly | 1 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Fuel Injection Pump (Governor) (1/2) (Inner Parts)(#210001-)
| DK***00 | Gasket | 1 |
| DK***20 | Flyweight Ass'Y | 1 |
| DK***00 | Shim? 2.00mm,(High Altitude Spec.) | 0 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Fuel Injection Pump (Governor) (2/2) (Inner Parts)(#210001-)
| DK***80 | Shim? 0.5mm | 0 |
| DK***00 | Washer,Spring | 1 |
| DK***80 | Bolt,Eye | 1 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Fuel Injection Pump (Pump) (1/2) (Inner Parts)(#210001-)
| 61***80 | Injection Pump Ass'Y | 1 |
| DK***30 | Bearing,Roller | 2 |
| DK***20 | Housing | 1 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Fuel Injection Pump (Pump) (2/2) (Inner Parts)(#210001-)
| DK***00 | Shim? 0.875mm | 0 |
| DK***00 | Shim? 0.500mm | 0 |
| DK***00 | Shim? 1.575mm | 0 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Fuel Injection Pump (Timer) (Inner Parts)(#210001-)
| DK***00 | O-Ring | 1 |
| DK***00 | Gasket | 1 |
| DK***00 | Plug | 1 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Fuel Injection Pump Drive(#61766-)
| 01***25 | Bolt,(For Canvas Canopy?Head Guard) | 4 |
| 01***14 | Nut (Itl) | 1 |
| 01***60 | Washer,(Without Rops Guard? Canopy) | 1 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Fuel Injection Pump Mounting(#210001-)
| 01***90 | Bolt,(For No?1 And No?3 Housing) | 4 |
| 01***16 | Washer,(With Water Separator) | 4 |
| 07***10 | Connector, Grease Fitting | 1 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Fuel Injection Pump Piping(#210001-)
| 01***30 | Screw | 4 |
| 01***45 | Bolt,(With Water Separator Type) | 2 |
| 01***55 | Bolt,(See Service News) | 4 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Fuel Pre Filter(#210085-)
| 01***25 | Bolt,(Rear Attachment Less) | 2 |
| 01***30 | Bolt,(With Body Positioner) | 2 |
| 01***23 | Washer, Wiring Harness Mounting Bracket | 2 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Fuel Return(#210001-)
| 01***20 | Bolt,(For Mono Lever Steering) | 1 |
| 01***16 | Washer,Radio Controlled Slag Handling | 2 |
| 04***10 | Clip,(With Accumulator) | 2 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Head Cover Related Parts (Cap)(#75758-)
| 07***50 | Cap,Oil Filler | 1 |
| 61***20 | Tube | 1 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Head Cover(#75758-)
| 01***16 | Washer,Radio Controlled Slag Handling | 24 |
| 61***11 | Cover,Head? No.2?3?4?5?6 | 5 |
| 61***51 | Cover,Head? No.6 | 1 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Hose And Clip (Ordering Transferded Parts)(#210001-)
| 07***50 | Hose, Right | 1 |
| 07***55 | Clip,94 | 1 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Idler Gear(#210001-)
| 01***60 | Capscrew | 1 |
| 01***25 | Bolt,(For Canvas Canopy?Head Guard) | 6 |
| 61***60 | Pin, Dowel | 1 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Injection Nozzle(#210001-)
| 01***45 | Bolt, Mount Divider Valve | 12 |
| 07***65 | O-Ring,Cylinder Block | 6 |
| 07***12 | Gasket,(Without Air Compressor Type) (K2) | 12 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Muffler(#210001-)
| 01***20 | Bolt,(For Mono Lever Steering) | 1 |
| 01***25 | Bolt,(For Canvas Canopy?Head Guard) | 4 |
| 01***40 | Bolt (Op) | 4 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Name Plate And Caution Plate(#210001-)
| 04***50 | Screw | 4 |
| 09***63 | Plate? Instruction,Air Cleaner (Single Element) | 1 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Nozzle Holder (Inner Parts)(#210001-)
| 07***12 | Gasket,Mechanical Pump Piping | 2 |
| 61***52 | Bolt, Joint | 1 |
| 61***10 | Fuel Injector Assembly | 6 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Oil Adapter(#210001-)
| 01***35 | Bolt,(F4320-52a0 -5 ) | 2 |
| 01***50 | Bolt,(Spark Arrester Spec.) | 4 |
| 01***08 | Nut,(For Canvas Canopy?Head Guard) | 1 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Oil Cooler Mounting Parts(#75758-)
| 01***25 | Bolt,(For Canvas Canopy?Head Guard) | 12 |
| 01***65 | Bolt - Return Line And Suction Linehose Clamps | 2 |
| 01***80 | Bolt,(With Corrosion Resistor) | 2 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Oil Cooler(#75758-)
| 01***25 | Bolt - Relay Mounting | 2 |
| 07***42 | O-Ring,(See Fig.A3310) | 1 |
| 61***25 | Cover | 1 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Oil Filter(#210001-)
| 01***30 | Bolt,(With Body Positioner) | 3 |
| 01***80 | Bolt,(With Corrosion Resistor) | 4 |
| 07***35 | O-Ring,Transmission Valve Mount | 1 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Oil Level Gauge(#210001-)
| 01***20 | Bolt,(For Mono Lever Steering) | 1 |
| 01***08 | Nut, Regular Hexagon (M10-1.50) | 1 |
| 01***16 | Washer,Radio Controlled Slag Handling | 2 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Oil Pan And Suction Tube(#210001-)
| 01***20 | Bolt,(For Mono Lever Steering) | 1 |
| 01***25 | Bolt,(For Canvas Canopy?Head Guard) | 27 |
| 01***30 | Bolt,(With Body Positioner) | 8 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Oil Pump
| 01***25 | Bolt,(Rear Attachment Less) | 4 |
| 01***25 | Bolt,(For Canvas Canopy?Head Guard) | 3 |
| 01***35 | Bolt,(F4320-52a0 -5 ) | 1 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Piston
| 02***13 | Pin, Dowel | 2 |
| 04***18 | Ring, Snap | 12 |
| 61***30 | Bushing,(Service Part) | 1 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Rocker Arm(#210001-)
| 01***75 | Screw | 37 |
| 01***90 | Bolt,(For No?1 And No?3 Housing) | 2 |
| 01***08 | Nut,R.H. Thread | 12 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Safety Guard (For Fuel Injection Pump Drive)(#77094-)
| 01***20 | Bolt,(For Mono Lever Steering) | 2 |
| 61***51 | Cover,Safety | 1 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Starting Motor (11kw) (Inner Parts)(#210001-)
| 60***11 | Starting Motor Ass'Y,(11kw) | 1 |
| KD***40 | Spring,Spring | 4 |
| KD***57 | Bearing, Ball, Front | 1 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Starting Motor Mounting (11kw)(#210001-)
| 01***40 | Bolt,(For Slag Handling) (For Usa) | 3 |
| 01***35 | Bolt, Mount Bracket To Floor | 1 |
| 01***32 | Washer,(With Auto Emergency Steering) | 1 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Tachometer Drive(#75758-)
| 01***75 | Screw | 2 |
| 01***32 | Washer,(With Auto Emergency Steering) | 2 |
| 61***31 | Gear,(With Air Compressor Type) | 1 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Turbocharger (Inner Parts)(#210001-)
| 61***20 | Turbocharger Ass'Y | 1 |
| SP***49 | V-Clamp | 1 |
| SP***65 | Nut, Lock | 2 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Turbocharger Oil Piping(#210001-)
| 01***20 | Bolt, Wiring Harness Mounting Bracket | 2 |
| 01***30 | Bolt - M8 X 30lg | 2 |
| 01***20 | Bolt,(For Mono Lever Steering) | 1 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Water Drain Valve
| 07***80 | Clamp, Drain Hose | 1 |
| 07***25 | Hose,Drain | 1 |
| 20***30 | Valve,Heat Water Inlet | 1 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Water Pump Gasket Kit(#210001-)
| 02***37 | O-Ring,(For Pc750?1800) (A5010) | 1 |
| 07***15 | O-Ring,(F4320-57a0 -11 ) | 1 |
| 61***90 | Gasket (K2?K6) | 1 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Water Pump(#75526-)
| 01***16 | Bolt - Seat And Tether Belt Mounting | 6 |
| 01***20 | Bolt,(For Mono Lever Steering) | 2 |
| 01***25 | Bolt,(For Canvas Canopy?Head Guard) | 2 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Water Separator And Piping(#210083-)
| 01***25 | Bolt,(For Canvas Canopy?Head Guard) | 2 |
| 01***30 | Bolt,(With Body Positioner) | 2 |
| 01***16 | Washer,Radio Controlled Slag Handling | 2 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Water Separator And Piping(#63385-)
| 01***30 | Bolt,(With Body Positioner) | 2 |
| 01***16 | Washer,Radio Controlled Slag Handling | 2 |
| 04***10 | Clip,(Without Cab) | 1 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Water Separator(#210083-)
| 07***12 | Gasket,Mechanical Pump Piping | 1 |
| 60***90 | O-Ring | 1 |
| 60***90 | Plug,Drain | 1 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Water Separator(#63385-)
| 07***12 | Gasket,Mechanical Pump Piping | 1 |
| 60***90 | O-Ring | 1 |
| 60***90 | Plug,Drain | 1 |
Komatsu : Saa6d125e-2d-8(S/N 60721-Up) : Engine : Water Temperature Sensor
| 07***12 | Washer, Gasket,(Without Thermo Sensor) (K1) | 1 |
| 78***20 | Sensor, Trans. Control Valve Oil Temperature | 1 |
SAA6D125E-2D-8(S/N 60721-UP) serial number reference
The engine serial number is stamped on the engine block, typically on the left side near the injection pump, and also appears on the metal data plate affixed to the engine. The prefix is the initial alphanumeric code (e.g., SAA6D125E-2D) found on this plate, identifying the engine family and generation before the specific serial digits.
| Prefix | Identifies | Notes |
|---|---|---|
| SAA6D125E-2D | Engine Model | Identified in the Equipment Guide as the engine for PC450LC-6K (S/N 210001-Up). This prefix is the base designation for the turbocharged, aftercooled engine family used in this serial range. |
| SA6D125E-2A-C | Engine Model | Identified in the Equipment Guide as the engine for PC600-6A-KJ / 6A-W1 (S/N 60721-Up). This prefix corresponds to the naturally aspirated variant within the 125-series block family. |
Frequently asked questions
What is the engine model?
Komatsu SAA6D125E-2D-8 (S/N 60721-UP)
What is the operating weight?
Varies by configuration/series: approx. 52,300-80,000 lb
What replaced it?
Electronically controlled SAA6D125E-3 and SAA6D125E-5 generations
What SAA6D125E-2D-8(S/N 60721-UP) owners discuss
What are the known powertrain and hydraulic behaviors for the Komatsu SAA6D125E-2D-8 engine?
The SAA6D125E-2D-8 is a turbocharged, aftercooled diesel engine. It is typically paired with Komatsu’s hydraulic systems that are sensitive to oil viscosity and temperature. A common diagnostic pattern is that hydraulic functions work normally when cold but become weak or sluggish as the oil warms up, indicating internal leakage in the main pump, control valve, or cylinders. The engine is designed for high torque at low RPM, but power loss under heavy digging load often points to restricted airflow or fuel delivery rather than engine failure. The hydraulic system requires specific Komatsu hydraulic oil to maintain proper viscosity and prevent cavitation or pump wear.
What undercarriage or wear patterns are typical for machines equipped with this engine series?
Machines with this engine series, such as the PC450-6K and PC600-6A, often exhibit wear patterns where the undercarriage components (track chains, rollers, and idlers) wear out simultaneously with the hydraulic pumps. This synchronized wear is a known characteristic of the design lifecycle. Operators should monitor track tension and roller condition closely, as mud or debris packed into the undercarriage can cause uneven wear and pulling to one side. The final drives are robust but require regular inspection for noise and oil leaks, which can indicate internal gear wear or seal failure.
What are the specific quirks of the SAA6D125E-2D-8 engine compared to related variants?
The SAA6D125E-2D-8 (S/N 60721-Up) is part of the 125-series block, distinct from the naturally aspirated 6D125E-2A and the later SAA6D125E-3 series. It features hardened cylinder liners matched to high-alloy piston rings, which are generally more durable than the soft liners found in some competing engines. The engine uses a Bosch-style fuel system with high injection pressure (approximately 3,200 PSI). A specific quirk is the sensitivity of the fuel pump drive gear; if the key securing the gear to the shaft fails, the low side of the fuel pump loses pressure under load, causing power loss. The engine is also known for reliable performance in heavy-duty applications, with a displacement of approximately 11 liters.
What are the common electrical or sensor issues associated with this engine?
Common electrical issues include intermittent starting, dashboard failures, and random shutdowns, often caused by unstable power supplies or faulty sensors. The oil pressure sensor is a frequent point of failure, leading to incorrect low-pressure readings even when the oil level and condition are correct. Clogged oil passages can also contribute to low oil pressure readings. Operators should check battery state of charge, ground connections, and starter relay circuits before diagnosing engine faults. Multiple fault codes often point to battery or ground issues rather than individual component failures.
What should be checked when buying a used machine with the SAA6D125E-2D-8 engine?
When purchasing a used machine with this engine, verify the exact serial number to confirm the engine model and configuration. Check the fuel pump drive gear key for wear or missing keys, as this is a known failure point. Inspect the cooling package (radiator, hydraulic oil cooler, charge-air cooler) for packed debris between the heat exchangers. Test the hydraulic system for performance differences between cold and hot operating temperatures. Check for aluminum traces in the transmission oil, which may indicate hydraulic pump wear. Verify the condition of the undercarriage and final drives, as these components often wear out in tandem with the hydraulic system.
What are the recommended fluid specifications for this engine?
Use Komatsu Genuine Diesel Engine Oil that meets Komatsu Engineering Standards. For the hydraulic system, use Komatsu Genuine Hydraulic Oil. The cooling system requires Super Coolant AF-NAC. Always verify the specific fluid grades and capacities in the Operation and Maintenance Manual for the exact machine model, as specifications can vary by configuration and series.
What is a safety-critical fix related to the fuel system on this engine?
If the fuel pump drive gear key fails, the low side of the fuel pump will not maintain sufficient pressure under load, causing severe power loss and potential engine damage. Have your dealer verify the integrity of the fuel pump drive gear key and the condition of the fuel pump shaft before operation. This is a critical safety and reliability fix that must be addressed immediately if suspected.
Compiled from owner and technician discussions across the industry — experiences vary by serial range and machine history.
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