Komatsuengine(no series)

Komatsu SAA6D125E-2B-8(S/N 60721-UP)

Maintenance schedule, common problems & OEM parts breakdown

Search live SAA6D125E-2B-8(S/N 60721-UP) parts

The Komatsu SAA6D125E-2B-8 (S/N 60721-UP) is a turbocharged, air-to-air aftercooled, six-cylinder inline diesel engine belonging to the 125-series family. It powers the mid-to-heavy class Komatsu D85 bulldozer series, a machine designed for construction, land leveling, and small-scale mining. The host dozer operates in the 29,300-31,000 kg (64,595-68,344 lb) weight range with a bucket capacity of 5.9-7.0 m³. This generation follows the earlier D65-8 series and precedes the D85EX-15/D85PX-15 generation. Komatsu offered the D85 platform in standard-gauge straight-tilt-blade configurations and wide-gauge, low-ground-pressure swamp variants, with the SAA6D125E-2B-8 fitted to the higher-output turbocharged models.

Across the 125-series lineage, the primary evolution moved from the naturally aspirated 6D125E-2A (used in the base D65E-12) to the turbocharged SAA6D125E-2B-8, and later to electronically controlled SAA6D125E-3 and SAA6D125E-5 variants. The SAA6D125E-2B-8 matters in the used and parts market because it bridges the gap between purely mechanical, flyweight-governed engines and modern electronic systems. It retains mechanical durability and straightforward diagnosis via warning lamps, avoiding complex ECM and wiring harness failures common in later Tier 3/Tier 4 models.

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-2B-8(S/N 60721-UP) specifications

Engine

Model	SAA6D125E-2B-8
Serial Range	60721-UP
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
Power (Gross/Net)	257 kW (345 hp) @ 1,900 rpm
Torque	1,370 N·m (1,010 lb·ft)
Emissions Tier	Not documented for this exact serial range — verify with your dealer

Weights

Operating Weight	Not documented for this exact serial range — verify with your dealer
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
Gradeability	Not documented for this exact serial range — verify with your dealer
Dig/Dump/Lift/Drawbar	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.

Komatsu SAA6D125E-2B-8(S/N 60721-UP) maintenance schedule

Service interval	Tasks
Every 10 h	Check engine oil level in the sump and add oil to the correct mark. Check coolant level in the radiator and top up with the correct antifreeze mix. Drain water and sediment from the fuel tank through the bottom valve. Check the air cleaner dust indicator and service the element if restricted. Walk around the machine and check for fuel, oil, and coolant leaks before starting. Check fan belt deflection (6-10 mm / 0.24-0.39 in) and adjust tension if loose.
Every 250 h	Grease the equalizer bar side pins and lift-cylinder ball-joint fittings. Check the final drive case oil level at the lower edge of the plug hole; add oil as needed. Check hydraulic tank oil level between the H and L marks on the sight gauge. Check battery electrolyte level and add distilled water as needed. Clean the fuel strainer and drain sediment from the fuel filter housing. Test brake holding capacity during the operational check.
Every 500 h	Change engine oil and replace the engine oil filter cartridge. Replace the fuel filter cartridge and bleed the fuel system. Replace the power train oil filter element and bleed air from the circuit. Check track tension and shoe bolt torque; adjust or retighten as needed. Perform KOWA (Komatsu Oil Wear Analysis) fluid sampling. Inspect undercarriage wear (bushing, sprocket segment, shoe height) against OEM minimums.
Every 1,000 h	Change the power train (transmission) oil and clean the strainers. Change the final drive case oil. Grease the universal joint fittings. Clean the power train case breather. Inspect ROPS and cab mounting bolts for looseness or damage. Test hydraulic oil for particle count and viscosity.
Every 2,000 h	Check the crankshaft vibration damper for damage or oil leakage. Check and clean the alternator and starting motor. Replace the hydraulic tank breather element. Check torque converter oil condition and top up or change if contaminated. Inspect structural welds on boom and stick for fatigue. Load test the battery and inspect alternator output.
Every 4,000 h	Change engine coolant system-wide, flush and refill with Komatsu Supercoolant/AF-NAC to the correct concentration. Check the water pump for shaft play, bearing noise, and coolant seepage; replace if worn. Check alternator and starting motor brushes; replace if worn below the service limit. Check torque converter oil for contamination; change if discolored or metallic. Flush and refill hydraulic system oil. Inspect turbocharger shaft play and boost pressure.

Servicing the SAA6D125E-2B-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 turbocharged 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 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-2B-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 →

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SAA6D125E-2B-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	Broken sensor, wiring issue, or connector corrosion	Replace the speed sensor and verify the voltage at the pin connector
CA111	Internal engine controller fault	ECM hardware failure	Replace or reprogram the ECM
CA451	Common rail pressure sensor feedback value too high	Malfunction in the rail sensor or actual overpressure condition	Diagnose the fuel rail pressure sensor or pump lines
CA122	Intake air pressure sensor feedback voltage too high	Sensor malfunction or wiring issue	Verify the intake pressure sensor and wiring
CA123	Intake air pressure sensor feedback voltage too low	Sensor short or airflow restriction	Check for a sensor short or an airflow restriction
CA441	Battery voltage too low	Alternator or battery failure	Replace the alternator or battery and check the voltage regulator
CA442	Battery voltage too high	Alternator or voltage regulator failure	Replace the alternator or battery and check the voltage regulator
CA234	Engine overspeed	Throttle calibration error, engine load cycle issue, or operator misuse	Verify throttle calibration, engine load cycle, or operator misuse
AA10NX	Air cleaner clogging	Dirty or blocked air filter element	Replace the air filter
B@BCNS	Engine coolant overheating	Radiator blockage, fan belt failure, or low coolant level	Check radiator fins, fan belt, and coolant level

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

SAA6D125E-2B-8(S/N 60721-UP) attachments & work tools

Excavator Buckets

The SAA6D125E-2B-8 engine (S/N 60721-Up) powers the PC400-6A and PC450-6A excavator series. Typical bucket capacities for this class range from 1.5 to 2.5 cubic meters (1.96 to 3.27 cubic yards) for standard digging applications. Factory configurations include heavy-duty rock buckets and grading buckets, mounted via standard excavator coupler systems compatible with the PC400/450-6A frame.

Wheel Loader Buckets

This engine specification is associated with the WA450-5 and WA470-5 wheel loader series. Standard bucket capacities for these models typically range from 3.0 to 4.0 cubic meters (3.92 to 5.23 cubic yards). Configurations include general purpose, light material, and heavy-duty rock buckets, utilizing standard loader coupler interfaces.

Bulldozer Blades

The SAA6D125E-2B-8 engine is used in the D85EX-2 series bulldozers. Typical blade capacities range from 7.0 to 8.0 cubic meters (9.16 to 10.46 cubic yards) for semi-U blades. Factory options include straight blades for fine grading and semi-U blades for heavy material movement, mounted via the standard dozer blade lift and tilt hydraulic circuits.

Hydraulic Tool Kits

Work tools for the PC400-6A/450-6A and WA450-5/470-5 series require specific hydraulic kit arrangements to support auxiliary functions such as breaker or grapple operation. Factory configurations include high-flow hydraulic lines and control valve options tailored to the SAA6D125E-2B-8 engine's power output and hydraulic pump capacity.

Undercarriage & Guarding

Notable factory configurations for the D85EX-2 and PC400/450-6A series include heavy-duty undercarriage components and side guards for mining or demolition environments. Options include rock shields, cab guards, and engine compartment guards, designed to protect the SAA6D125E-2B-8 engine and hydraulic systems from debris impact.

All SAA6D125E-2B-8(S/N 60721-UP) assemblies by section

Every catalogued assembly group for the Komatsu SAA6D125E-2B-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-2b-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
61***30	Hose	1

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Komatsu : Saa6d125e-2b-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
01***45	Bolt,(With Water Separator Type)	2

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Komatsu : Saa6d125e-2b-8(S/N 60721-Up) : Engine : Air Intke Manifold (Without Corro.Rstr.)(#211198-)

01***25	Bolt,(For Canvas Canopy?Head Guard)	6
01***30	Bolt,(With Body Positioner)	12
01***70	Bolt - Bracket And Oil Inlet Tubemounting	5
01***75	Bolt (M10-1.50x75)	1

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Komatsu : Saa6d125e-2b-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
01***75	Bolt (M10-1.50x75)	1

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Komatsu : Saa6d125e-2b-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

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Komatsu : Saa6d125e-2b-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
SD***X0	Fan	1

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Komatsu : Saa6d125e-2b-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
01***30	Bolt	4

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Komatsu : Saa6d125e-2b-8(S/N 60721-Up) : Engine : Camfollower Cover

07***20	Clamp, Spring Hose	1
07***85	Hose	1
61***90	O-Ring,Breather	1
61***91	Packing,(See Fig.A2060)	9

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Komatsu : Saa6d125e-2b-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
61***12	Camshaft Assembly	1

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Komatsu : Saa6d125e-2b-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

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Komatsu : Saa6d125e-2b-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
07***12	Gasket,(Without Air Compressor Type) (K1)	4

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Komatsu : Saa6d125e-2b-8(S/N 60721-Up) : Engine : Crank Pulley

Komatsu : Saa6d125e-2b-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
61***50	Bearing, Thrust Assembly (1.00mm Oversize)	1

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Komatsu : Saa6d125e-2b-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
01***12	Bolt,(Without Air Compressor Type)	2

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Komatsu : Saa6d125e-2b-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
07***25	O-Ring (K2?K8)	1

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Komatsu : Saa6d125e-2b-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
01***45	Washer,(For Travel Motor) (Not Show)	14

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Komatsu : Saa6d125e-2b-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
07***12	Gasket,(Without Air Compressor Type) (K1)	4

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Komatsu : Saa6d125e-2b-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
07***10	Plug, Expansion	1

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Komatsu : Saa6d125e-2b-8(S/N 60721-Up) : Engine : Damper

01***25	Bolt,(Without Rops Guard? Canopy)	6
61***00	Damper Assembly	1

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Komatsu : Saa6d125e-2b-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
01***25	Bolt,(For Canvas Canopy?Head Guard)	2

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Komatsu : Saa6d125e-2b-8(S/N 60721-Up) : Engine : Exhaust Manifold

01***00	Bolt (M10-1.50x100)	16
01***80	Bolt	2
01***00	Screw	16
01***80	Bolt	2

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Komatsu : Saa6d125e-2b-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
01***16	Washer,(With Water Separator)	4

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Komatsu : Saa6d125e-2b-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

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Komatsu : Saa6d125e-2b-8(S/N 60721-Up) : Engine : Flywheel Housing

01***50	Capscrew	6
01***60	Capscrew	2
01***50	Bolt,(Spark Arrester Spec.)	2
01***16	Bolt - Starting Motor Ground Cable	1

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Komatsu : Saa6d125e-2b-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
61***00	Flywheel Ass'Y	1

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Komatsu : Saa6d125e-2b-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
01***30	Bolt	1

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Komatsu : Saa6d125e-2b-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
61***41	Cover,Front	1

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Komatsu : Saa6d125e-2b-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
01***45	Bolt, Mount Divider Valve	1

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Komatsu : Saa6d125e-2b-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
DK***00	Bolt	1

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Komatsu : Saa6d125e-2b-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
DK***20	Pump, Priming	1

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Komatsu : Saa6d125e-2b-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
DK***10	Key? 13mm,Woodruff	1

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Komatsu : Saa6d125e-2b-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
DK***00	Gasket	1

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Komatsu : Saa6d125e-2b-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
DK***00	Bearing, Center	1

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Komatsu : Saa6d125e-2b-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
DK***20	Plunger Ass'Y	1

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Komatsu : Saa6d125e-2b-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
DK***00	Pin,Pilot	2

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Komatsu : Saa6d125e-2b-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
04***19	Key,(For Mechanical Governor)	1

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Komatsu : Saa6d125e-2b-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
61***10	Connector, Banjo	1

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Komatsu : Saa6d125e-2b-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
01***75	Bolt (M10-1.50x75)	2

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Komatsu : Saa6d125e-2b-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
61***71	Distance Piece	1

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Komatsu : Saa6d125e-2b-8(S/N 60721-Up) : Engine : Head Cover Related Parts (Cap)(#75758-)

07***50	Cap,Oil Filler	1
61***20	Tube	1

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Komatsu : Saa6d125e-2b-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
61***10	Gasket,Cylinder Head Cover	6

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Komatsu : Saa6d125e-2b-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
61***11	Journal	1

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Komatsu : Saa6d125e-2b-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
07***09	Tube,Spill	2

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Komatsu : Saa6d125e-2b-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
01***16	Bolt	4

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Komatsu : Saa6d125e-2b-8(S/N 60721-Up) : Engine : Name Plate And Caution(#210002-)

04***50	Screw	4
60***20	Plate? Instruction	1
61***10	Plate? License,(Limited Supply)	1
61***20	Plate? Name,(Limited Supply)	1

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Komatsu : Saa6d125e-2b-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
DK***00	Spacer	1

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Komatsu : Saa6d125e-2b-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
01***16	Washer,Radio Controlled Slag Handling	5

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Komatsu : Saa6d125e-2b-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
01***16	Washer,Radio Controlled Slag Handling	16

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Komatsu : Saa6d125e-2b-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
61***41	Sleeve	1

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Komatsu : Saa6d125e-2b-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
60***30	Plug	1

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Komatsu : Saa6d125e-2b-8(S/N 60721-Up) : Engine : Oil Level Gauge(#210002-)

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
04***10	Clip	1

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Komatsu : Saa6d125e-2b-8(S/N 60721-Up) : Engine : Oil Pan And Suction Tube(#210002-)

01***20	Bolt,(For Mono Lever Steering)	1
01***25	Bolt,(For Canvas Canopy?Head Guard)	27
01***30	Bolt,(With Body Positioner)	8
01***35	Bolt,(F4320-52a0 -5 )	3

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Komatsu : Saa6d125e-2b-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
01***32	Washer,(With Auto Emergency Steering)	1

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Komatsu : Saa6d125e-2b-8(S/N 60721-Up) : Engine : Piston

Komatsu : Saa6d125e-2b-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
01***32	Washer,(With Auto Emergency Steering)	37

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Komatsu : Saa6d125e-2b-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

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Komatsu : Saa6d125e-2b-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
KD***30	Armature Assembly	1

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Komatsu : Saa6d125e-2b-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
04***10	Clip,(With Accumulator)	1

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Komatsu : Saa6d125e-2b-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

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Komatsu : Saa6d125e-2b-8(S/N 60721-Up) : Engine : Turbocharger (Inner Parts)(#210002-)

61***20	Turbocharger Ass'Y	1
SP***49	V-Clamp	1
SP***65	Nut, Lock	2
SP***55	Housing, Turbine	1

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Komatsu : Saa6d125e-2b-8(S/N 60721-Up) : Engine : Turbocharger Oil Piping(#210002-)

01***20	Bolt, Wiring Harness Mounting Bracket	2
01***30	Bolt - M8 X 30lg	2
01***20	Bolt,(For Mono Lever Steering)	1
01***25	Bolt,(For Canvas Canopy?Head Guard)	2

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Komatsu : Saa6d125e-2b-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

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Komatsu : Saa6d125e-2b-8(S/N 60721-Up) : Engine : Water Line Plug (Without Corro.Rstr.)(#211198-)

01***16	Washer,Radio Controlled Slag Handling	1
07***12	Gasket,(Without Air Compressor Type) (K1)	2
61***10	Plug,(Without Air Compressor Type)	2
61***70	Screw	1

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Komatsu : Saa6d125e-2b-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
61***10	Seal,Water (K6)	1

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Komatsu : Saa6d125e-2b-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
01***30	Bolt,(With Body Positioner)	2

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Komatsu : Saa6d125e-2b-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

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SAA6D125E-2B-8(S/N 60721-UP) serial number reference

The engine serial number plate is typically located on the left side of the engine block near the injection pump. The prefix is the first six digits of the serial number stamped on the plate or block.

Prefix	Identifies	Notes
60721-UP	SAA6D125E-2B-8	Engine serial range for SAA6D125E-2B-8. Source: DK Engine Parts equipment guide.

Frequently asked questions

What is the engine model for the Komatsu SAA6D125E-2B-8 (S/N 60721-UP)?

The engine is a Komatsu SAA6D125E-2B-8, a turbocharged, air-to-air aftercooled, six-cylinder inline diesel from the 125-series family.

What is the operating weight of the host machine?

The operating weight varies by configuration/series: approximately 29,300-31,000 kg (64,595-68,344 lb) depending on the blade, ripper, and dash-suffix variant fitted to the host D85 dozer.

What replaced the SAA6D125E-2B-8 engine?

The SAA6D125E-2B-8 was succeeded by the electronically controlled, turbo-aftercooled SAA6D125E-3 and later SAA6D125E-5 engines, which replaced the mechanical fuel system and flyweight governor with electronic management systems.

What SAA6D125E-2B-8(S/N 60721-UP) owners discuss

How does the SAA6D125E-2B-8 fuel system design compare to contemporary Cummins units in terms of durability?

The SAA6D125E-2B-8 utilizes a Bosch-style fuel system with injectors operating at 3,200 PSI. This contrasts with the Cummins units often found in similar applications, which used a PT fuel system with injection pressures around 2,100 PSI. The Komatsu design features hardened cylinder liners and high-alloy piston rings, whereas competing Cummins units were prone to piston ring failure around 4,000 hours. Community consensus indicates the Komatsu engine is significantly more durable than the Cummins alternative in this class.

What are the typical powertrain and hydraulic behaviors associated with this engine series?

The engine is rated at 275 horsepower (205 kilowatts) with a torque of 1,010 pound-feet (1,370 Newton meters). It delivers a fuel consumption rate of approximately 18.5 gallons per hour (70 liters per hour) at rated power. The engine is turbocharged with an air-to-air aftercooler. Hydraulic systems paired with this engine often exhibit slow movements or sluggish controls when overheating occurs, particularly in cold conditions where the machine struggles to lift the boom after extended operation. Have your dealer verify hydraulic flow settings against the specific machine model.

What undercarriage or wear patterns are typical for machines equipped with this engine?

Machines using this engine, such as the D85 dozer and PC400/PC450 excavators, feature durable undercarriage systems designed for diverse working conditions. Common wear patterns include final drive grinding noises, particularly on the right side in tracked excavators. Operators report that slow travel or grinding sounds often indicate final drive issues. The undercarriage is engineered for heavy earthmoving, but wear accelerates under continuous load and dust exposure.

What are the common electrical or sensor issues reported for this engine series?

Komatsu excavators rely heavily on electronic control systems. A single faulty sensor or unstable power supply can trigger multiple warning signals. Common issues include intermittent starting, dashboard failure, and random shutdowns. Fault codes such as E10 indicate engine controller power failure or engine management system malfunction, while E11 signals engine control failure resulting in reduced output power to protect the engine. E15 codes point to engine sensor malfunctions regarding temperature, fuel pressure, or oil pressure.

What specific fuel system quirks or failures are documented for this series?

A documented failure mode involves the low side of the fuel pump failing to maintain sufficient pressure under load. In some instances, the key securing the fuel pump drive gear to the shaft was found missing, leading to poor performance. The engine uses a Bosch-style high-pressure injection system. Operators should monitor for loss of power, increased fuel usage, or overheating, which may signal airflow restriction, injector wear, or failing fuel delivery components.

What maintenance intervals and fluid specifications are standard for this engine?

Komatsu planned maintenance follows a tiered hour-based structure at 250, 500, 1,000, and 2,000 hours. Komatsu Oil Wear Analysis (KOWA) is recommended at each major service interval. Komatsu Genuine Oil and Super-coolant AF-NAC are specified. The engine displacement is 11.04 liters (674 cubic inches) with a bore of 4.49 inches (114 mm) and stroke of 5.69 inches (144.5 mm). Have your dealer verify fluid capacities for the specific machine model and ambient temperature.

What should be checked when buying a used machine with the SAA6D125E-2B-8 engine?

Verify the engine serial number prefix to confirm it matches the SAA6D125E-2B-8 designation (S/N 60721-Up). Check for signs of low-side fuel pump pressure loss or missing drive gear key. Inspect final drives for grinding noises, especially on the right side. Test for intermittent starting or random shutdowns which indicate electrical or sensor faults. Verify the condition of hardened liners and high-alloy rings if the engine has been overhauled.

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

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