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Komatsu SAA6D125E-3H-8M(S/N 310001-UP)

Maintenance schedule, common problems & OEM parts breakdown

Search live SAA6D125E-3H-8M(S/N 310001-UP) parts

The Komatsu SAA6D125E-3H-8M engine powers the PC400-7 and PC450-7 series hydraulic crawler excavators, a mid-size class of heavy earthmoving equipment with operating weights ranging from approximately 39,000 to 45,000 lb (17,700 to 20,400 kg). Produced during the dash-7 generation (2002–2007), this Tier 3/Stage IIIA compliant unit succeeded the dash-6 series predecessors and was later replaced by the dash-8 generation machines equipped with the SAA6D125E-5 engine. The engine delivers 345 to 347 hp at 1,900 rpm and features a 6-cylinder, 11.0-liter displacement with variable geometry turbocharging and air-to-air aftercooling.

The SAA6D125E-3H-8M represents a critical transition point in Komatsu's heavy excavator lineup, bridging the gap between pre-emissions Tier 2 designs and modern Tier 4 Final requirements. Its robust Bosch-style fuel system and hardened liner architecture established a reputation for high durability that continues to drive the used parts market. As original dash-7 excavators reach high-hour milestones, the demand for reliable inframe overhaul kits, cylinder liners, and electronic components remains strong, making this engine a staple for fleet maintenance and rebuild programs.

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-3H-8M(S/N 310001-UP) specifications

Engine

Model	SAA6D125E-3H-8M (S/N 310001-UP)
Gross Power	259 kW (347 hp) @ 1850 rpm
Net Power	257 kW (345 hp) ISO 9249 @ 1900 rpm
Displacement	11.04 L (674 in³)
Cylinders	6
Emissions Tier	Tier 2
Aspiration	Turbocharged, air-to-air aftercooled

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
Digging Force	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-3H-8M(S/N 310001-UP) maintenance schedule

Service interval	Tasks
Every 10 h	Check engine oil level and condition. Check hydraulic fluid level via sight glass. Check coolant level and ensure cap is secure. Check fuel level and drain water from separator. Check DEF level on Tier 4 machines. Check air filter restriction indicator.
Every 250 h	Change engine oil and filter. Grease all points including boom, stick, bucket, and swing bearing. Check fluid levels. Check air filter outer element. Inspect belts and hoses. Perform visual walk-around inspection.
Every 500 h	Replace fuel filter. Replace hydraulic return filter. Perform battery load test. Test coolant SCA concentration. Collect KOWA oil sample. Perform detailed undercarriage inspection.
Every 1,000 h	Change hydraulic oil. Change final drive oil on both sides. Inspect turbocharger. Take wear measurements. Check valve adjustment. Perform structural inspection.
Every 2,000 h	Flush and replace coolant. Service transmission. Perform comprehensive component evaluation. Check KDPF (at 4,500 hr intervals). Replace worn belts and hoses. Load test battery and alternator.

Servicing the SAA6D125E-3H-8M(S/N 310001-UP) beyond the schedule

Predictive Maintenance & Fluid Analysis

Implement Komatsu KOWA fluid analysis at every 500-hour service interval to monitor wear metals and contaminants in the SAA6D125E-3H-8M engine. Track iron, copper, and lead levels to detect early bearing or liner wear. Monitor coolant pH and SCA concentration to prevent scaling and corrosion in the 11.0-liter cooling system. Analyze hydraulic oil for particle count and viscosity changes to protect the PC400-7/PC450-7 hydraulic pumps. Use KOMTRAX telematics data to correlate load frequency with fluid degradation rates for optimized change intervals.

Corrective & Common Repairs

Address low oil pressure in the SAA6D125E-3H-8M by inspecting the oil pressure sensor and clearing clogged oil passages common in high-hour units. Repair fuel system issues by verifying the fuel pump drive gear key integrity, a known failure point under load. Replace worn piston rings and liners if compression drops below spec. Diagnose electronic faults using Komatsu monitor panel codes for EPC system or engine controller power failures. Replace the turbocharger if boost pressure anomalies indicate seal wear or turbine damage.

Overhaul & Rebuild Points

Perform an inframe overhaul on the SAA6D125E-3H-8M when cylinder liner wear or piston ring groove damage compromises compression. Replace all six cylinder liners, pistons, and ring sets using Komatsu overhaul kits. Inspect the crankshaft for journal wear and replace bearings if clearances exceed limits. Rebuild the fuel injection pump and replace injectors if spray patterns are erratic. Check the turbocharger shaft play and replace seals. Ensure the ECM harness is intact and free of chafing during reassembly.

Seasonal & Environment Servicing

In cold climates, ensure the SAA6D125E-3H-8M uses Komatsu Super Coolant AF-NAC rated for the local minimum temperature. Check the battery hold-down and terminals for corrosion before winter starts. In dusty environments, inspect the air filter restriction indicator frequently and clean the radiator and oil cooler fins daily to prevent overheating. Verify the DEF tank level and heater function for Tier 3 machines operating in regulated zones. Grease all undercarriage pins and bushings more often in abrasive conditions to extend track life.

SAA6D125E-3H-8M(S/N 310001-UP) common service parts

Part number	Part	Notes
07281-00197	Clamp,(With Pre-Fuel Filter)	Fuel system service	Check fitment →
600-311-8321	Cartridge,Fuel Filter	Fuel system service	Check fitment →
6127-71-6501	Fuel Filter Ass'Y	Fuel system service	Check fitment →
6152-62-2210	Element, Oil Cooler	Lubrication service	Check fitment →
600-211-1340	Cartridge, Oil Filter	Lubrication service	Check fitment →

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

SAA6D125E-3H-8M(S/N 310001-UP) fault codes & troubleshooting

Code	Meaning	Likely cause	What to do
E10	Engine controller power failure or engine control drive system circuit malfunction.	Faulty ECM power connections, blown fuses, or damaged ground wires.	Inspect ECM power connections, fuses, and ground wires for continuity and corrosion.
CA115	Engine crankshaft speed sensor and backup speed sensor failure.	Broken sensor, wiring issue, or connector corrosion.	Replace the speed sensor and verify voltage at the pin connector.
CA441	Battery voltage is too low.	Weak battery, failing alternator, or loose connections.	Replace the alternator or battery; check the voltage regulator.
CA451	Common rail pressure sensor feedback value is too high.	Malfunction in the rail sensor or actual overpressure condition.	Diagnose the fuel rail pressure sensor or check pump lines.
AA10NX	Air cleaner clogging.	Dirty or blocked air filter element.	Replace the air filter.
B@BCNS	Engine coolant overheating.	Low coolant level, blocked radiator fins, or fan belt failure.	Check radiator fins, fan belt, and coolant level.
B@HANS	Hydraulic oil overheating.	Contaminated hydraulic oil, clogged filter, or cooler fan issue.	Change hydraulic filter and oil; check cooler fan operation.
CA234	Engine overspeed.	Throttle calibration error, engine load cycle issue, or operator misuse.	Verify throttle calibration and engine load cycle.
CA111	Internal engine controller fault.	ECM internal hardware failure.	Replace or reprogram the ECM.
CA689	Engine speed sensor fault.	Failed speed sensor or signal phase abnormality.	Replace the corresponding sensor or inspect the sensor gap.

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

SAA6D125E-3H-8M(S/N 310001-UP) attachments & work tools

Excavator Work Tools

The SAA6D125E-3H-8M engine powers the PC400LC-7 and PC450-7 excavator series, which utilize standard excavator buckets ranging from 1.5 to 2.5 cubic meters (1.15 to 1.91 cu yd) depending on material density and stick length. Factory configurations include standard and heavy-duty bucket options with varying tooth profiles and side-cutting edges to match excavation duty cycles.

Wheel Loader Work Tools

For the WA470-5 and WA480-5 wheel loader series, typical bucket capacities range from 3.0 to 4.2 cubic meters (3.9 to 5.5 cu yd) for general material handling. Optional work tools include rock buckets with reinforced cutting edges and specialized grading buckets for fine finishing work.

Bulldozer Work Tools

The D85EX-15 series dozers equipped with this engine class typically feature straight blades with capacities around 7.0 to 8.0 cubic meters (9.16 to 10.46 cu yd) for standard earthmoving. Optional configurations include semi-U blades for improved material retention and ripper attachments for breaking hard ground or rock.

Coupler and Mounting Systems

Excavator models utilize standard pin-on bucket mounting systems compatible with Komatsu’s proprietary quick coupler options for rapid tool changes. Wheel loaders employ a skid-steer style quick attach mechanism or standard bucket pins, depending on the specific WA series configuration and regional market requirements.

Hydraulic Kit Requirements

Work tools requiring auxiliary hydraulic functions, such as tilt rotators or hydraulic breakers, require specific auxiliary hydraulic kits and valve assemblies installed by the dealer. These kits must match the machine’s main pump flow and pressure settings, which vary by configuration and series.

Factory Guarding and Protection

Factory options include heavy-duty undercarriage guards, rock shields for the radiator and hydraulic lines, and reinforced boom and stick structures for high-abrasion applications. These guarding packages are selected based on the intended work environment to protect critical engine and hydraulic components from damage.

All SAA6D125E-3H-8M(S/N 310001-UP) assemblies by section

Every catalogued assembly group for the Komatsu SAA6D125E-3H-8M(S/N 310001-UP). Open an assembly to preview the parts inside — full OEM part numbers are available in Heavy Parts AI.

Engine

Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : After Cooler

61***90	Clamp, Hose	4
61***30	Hose	1
61***40	Hose	1
61***00	After Cooler Ass'Y	1

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Air Cleaner(#310521-)

01***16	Bolt - Starting Motor Ground Cable	1
01***25	Bolt, Mount Engine Oil Drain To Fuel Tank	4
07***12	Gasket,(Without Air Compressor Type) (K2)	4
07***08	Plug,(Without Auto Priming System)	1

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Air Intake Manifold And Air Connection(#310521-)

01***50	Bolt	2
01***12	Bolt,(Without Air Compressor Type)	1
01***20	Bolt, Hose Clamps (Inlet And Return Line Hoses)	2
01***25	Bolt, Mount Engine Oil Drain To Fuel Tank	4

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Air Vent(#310521-)

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-3h-8m(S/N 310001-Up) : Engine : Alternator (35a) (Inner Parts)

60***21	Alternator A. (35a)	1
KD***70	Bushing,Insulate	1
KD***40	Bushing,Insulate	1
KD***30	Collar,Insulate	1

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Alternator (50a) (Inner Parts)

60***20	Alternator A. (50a),(See Fig.A6010-B3s6)	1
KD***21	Rear Bracket Assembly	1
KD***70	Bushing,Insulate	1
KD***40	Bushing,Insulate	1

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Alternator (75a) (Inner Parts)(#310001-310944)

60***40	Alternator A. (75a),(With Non Hardening Pulley)	1
SD***X0	Coil Assembly	1
SD***X0	Bracket, Rear	1
SD***X0	Bearing, Ball	1

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Alternator Mounting (35a)

01***60	Screw	1
01***25	Bolt, Mount Engine Oil Drain To Fuel Tank	4
01***85	Bolt,(For Reversible Fan)	2
01***55	Bolt,(With Joy Stick Steering)	1

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Alternator Mounting (50a)

01***60	Screw	1
01***25	Bolt, Mount Engine Oil Drain To Fuel Tank	4
01***85	Bolt,(For Reversible Fan)	2
01***55	Bolt,(With Joy Stick Steering)	1

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Alternator Mounting (75a)

01***60	Screw	1
01***25	Bolt, Mount Engine Oil Drain To Fuel Tank	4
01***85	Bolt,(For Reversible Fan)	2
01***55	Bolt,(With Joy Stick Steering)	1

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Camfollower Cover And Oil Filler(#310521-)

01***20	Bolt, Hose Clamps (Inlet And Return Line Hoses)	4
01***08	Nut,See Fig. K4010-04a0	2
07***09	Clamp, Hose	2
07***20	Clamp, Spring Hose	1

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Camshaft And Camfollower(#310521-)

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-3h-8m(S/N 310001-Up) : Engine : Corrosion Resistor

01***16	Bolt - Starting Motor Ground Cable	1
01***30	Bolt - Lower Oil Cooler Outlet Tubemounting	4
01***45	Bolt, Bracket Mounting	1
02***32	Bolt,(With Joy Stick Steering)	4

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Crank Pulley

01***80	Screw	1
01***85	Screw	5
04***24	Pin,Dowel (For No.3 Housing)	1
61***61	Washer, Plain (14mm)	1

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Crankshaft(#310314-)

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-3h-8m(S/N 310001-Up) : Engine : Cylinder Block Blind Cover And Oil Pressure Switch (Cold Terrain Spec.)(#310710-)

01***20	Bolt,(For Mono Lever Steering)	4
01***25	Bolt,(For Canvas Canopy?Head Guard)	4
01***12	Bolt,(Without Air Compressor Type)	2
01***25	Bolt, Mount Engine Oil Drain To Fuel Tank	1

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Cylinder Block Blind Cover And Oil Pressure Switch(#310521-)

01***20	Bolt,(For Mono Lever Steering)	4
01***25	Bolt,(For Canvas Canopy?Head Guard)	4
01***12	Bolt,(Without Air Compressor Type)	2
01***20	Bolt, Hose Clamps (Inlet And Return Line Hoses)	2

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Cylinder Block Gasket Kit(#310521-)

07***21	O-Ring,Water Piping	1
07***30	Ring, Seal - Between Sections	1
07***50	O-Ring,Front Cover Plate	1
07***42	O-Ring,(See Fig.A3310)	1

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Cylinder Block(#310521-)

01***16	Bolt, Mount Solenoid Valve	6
01***45	Washer,(For Travel Motor) (Not Show)	14
04***14	Pin, Dowel	2
04***20	Pin,Dowel (Welded)	12

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Cylinder Head Gasket Kit(#310521-)

07***65	O-Ring,Cylinder Block	6
07***11	O-Ring,(See Fig.A4210)	6
07***20	O-Ring,(See Fig.A4210)	12
07***24	O-Ring (K1)	6

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Cylinder Head(#310521-)

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-3h-8m(S/N 310001-Up) : Engine : Damper

01***20	Bolt - Mount Risers To Cab Floor	6
61***00	Damper	1

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Engine Mounting

01***55	Bolt,(See Service News)	1
01***00	Bolt,(For Front Brake Release)	2
01***05	Capscrew	2
01***10	Bolt,(With Joy Stick Steering)	5

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Exhaust Manifold

01***80	Screw	18
07***08	Plug,(Without Auto Priming System)	1
61***20	Spacer,(For Shipping)	18
61***10	Gasket,Exhaust Manifold	6

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Flywheel Housing(#310521-)

01***25	Bolt,(For Shipping)	1
01***50	Capscrew	6
01***60	Capscrew	4
01***30	Capscrew (1)	1

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Flywheel(#310521-)

01***60	Bolt	6
01***45	Washer,(For Travel Motor) (Not Show)	6
61***41	Gear, Ring	1
61***60	Flywheel Ass'Y	1

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Front Cover

09***50	Liquid Gasket, Lg-7, 150g	0
61***30	Seal? Front (K2)	1
61***10	Cover, Front	1

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Front Cover Accessory Parts

01***16	Bolt, Mounting Transmission Control Switch	2
01***20	Bolt, Hose Clamps (Inlet And Return Line Hoses)	2
01***70	Screw	3
01***75	Bolt (M10-1.50x75)	8

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Front Cover Accessory Parts (With Tachometer Drive)(#310828-)

01***20	Bolt,See Fig. K4010-11a0	2
01***20	Bolt, Hose Clamps (Inlet And Return Line Hoses)	2
01***70	Screw	3
01***75	Bolt (M10-1.50x75)	8

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Front Hanger

01***85	Bolt,(For Reversible Fan)	4
61***61	Spacer	1
61***10	Plate, Hanger	1

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Fuel Filter (2 Filter Type)(#310521-)

01***25	Bolt, Mount Engine Oil Drain To Fuel Tank	2
01***35	Bolt, Mount Bracket To Floor	1
01***45	Bolt, Bracket Mounting	2
07***12	Gasket,Mechanical Pump Piping	2

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Fuel Filter(#310521-)

01***30	Bolt,(With Body Positioner)	2
07***12	Gasket,(Without Air Compressor Type) (K1)	5
07***14	Screw, Banjo Connector (M10)	2
07***45	Hose	1

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Fuel Injection Pump (Coupling) (Inner Parts)(#310521-)

DK***00	Nut	2
DK***00	Bolt	2
DK***20	Coupling Ass'Y	1
DK***00	Bolt	1

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Fuel Injection Pump (Feed Pump) (Inner Parts)(#310521-)

DK***20	Bolt, Joint	1
DK***00	Valve,Check	2
DK***20	Pump, Priming	1
DK***20	Housing,Feed Pump	1

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Fuel Injection Pump (Governor) (1/2) (Inner Parts)(#310521-)

DK***00	Gasket	1
DK***20	Flyweight Ass'Y	1
DK***00	Shim? 2.00mm,(High Altitude Spec.)	0
DK***20	Limiter	1

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Fuel Injection Pump (Governor) (2/2) (Inner Parts)(#310521-)

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-3h-8m(S/N 310001-Up) : Engine : Fuel Injection Pump (Pump) (1/2) (Inner Parts)(#310521-)

61***10	Fuel Pump Ass'Y	1
DK***30	Bearing,Roller	2
DK***00	Camshaft	1
DK***00	Shim? 0.50mm	0

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Fuel Injection Pump (Pump) (2/2) (Inner Parts)(#310521-)

DK***00	Shim? 0.875mm	0
DK***00	Shim? 0.500mm	0
DK***00	Shim? 1.575mm	0
DK***00	Shim? 1.075mm	0

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Fuel Injection Pump (Timer) (Inner Parts)(#310521-)

DK***00	O-Ring	1
DK***00	Gasket	1
DK***10	Timer Ass'Y	1
DK***00	Plug	1

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Fuel Injection Pump Drive(#310521-)

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-3h-8m(S/N 310001-Up) : Engine : Fuel Injection Pump Mounting(#310521-)

01***90	Bolt,(For No?1 And No?3 Housing)	4
01***16	Washer,(With Water Separator)	4
07***12	Gasket,(Without Air Compressor Type) (K2)	2
07***10	Screw, Banjo Connector (M10-1.25x20)	1

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Fuel Injection Pump Piping(#310521-)

01***45	Bolt,(With Water Separator Type)	2
01***75	Bolt (M10-1.50x75)	2
01***30	Bolt,See Fig. K4010-17a0	4
01***35	Bolt	4

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Fuel Return(#310521-)

07***16	Tube,Spill (S6d110-1a? S6d110-1b)	1
07***85	Clip	1

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Head Cover(#310521-)

01***16	Washer,Radio Controlled Slag Handling	24
61***11	Cover,Head? No.2?3?4?5?6	6
61***10	Gasket,Cylinder Head Cover	6
61***20	Rubber,(Fig.A1111)	12

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Heater Switch

01***12	Bolt,(See Fig. K0210-16a0)	2
01***75	Bolt (M10-1.50x75)	1
01***16	Washer,Radio Controlled Slag Handling	2
08***19	Cap, At Heater Relay Terminals	2

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Idler Gear

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-3h-8m(S/N 310001-Up) : Engine : Injection Nozzle(#310521-)

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-3h-8m(S/N 310001-Up) : Engine : Muffler(#310521-)

01***25	Bolt,Joint	4
01***50	Bolt	2
01***25	Capscrew	1
01***40	Screw	4

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Name Plate And Caution (Japanese-English) (Regulation Of Epa )(#310521-)

04***50	Screw	4
60***40	Plate? Name,(Limited Supply)	1
60***40	Plate? Name,Engine (Limited Supply)	1

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Name Plate And Caution (Japanese-English) (Regulation Of Epa 2nd And Eu 2nd)(#310521-)

04***50	Screw	4
61***40	Plate	1

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Nozzle Holder (Inner Parts)(#310521-)

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-3h-8m(S/N 310001-Up) : Engine : Oil Cooler

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-3h-8m(S/N 310001-Up) : Engine : Oil Cooler Mounting Parts

01***25	Bolt, Mount Engine Oil Drain To Fuel Tank	12
01***65	Bolt, Mount Tube To Divider Valve	2
01***80	Bolt (M10-1.50x80)	2

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Oil Filter And Piping

01***25	Bolt, Mount Engine Oil Drain To Fuel Tank	7
01***35	Bolt, Mount Bracket To Floor	8
07***25	O-Ring,Lubrication Valve	2
07***25	O-Ring,(For Pc1800e-6)(See Fig.A3110)	2

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Oil Level Gauge(#310521-)

61***20	Collar	1
61***30	Nut,(For Shipping)	1
61***51	Gauge, Oil Level	1
61***40	Guide,Oil Gauge	1

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Oil Level Gauge(#310710-)

61***20	Collar	1
61***30	Nut,(For Shipping)	1
61***51	Gauge, Oil Level	1
61***40	Guide,Oil Gauge	1

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Oil Pan And Suction Tube (Cold Terain Spec.)(#310710-)

01***20	Bolt,(For Mono Lever Steering)	1
01***25	Bolt,(For Canvas Canopy?Head Guard)	1
01***35	Bolt,(F4320-52a0 -5 )	2
01***16	Bolt - Starting Motor Ground Cable	1

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Oil Pan And Suction Tube(#310521-)

01***20	Bolt,(For Mono Lever Steering)	1
01***25	Bolt,(For Canvas Canopy?Head Guard)	1
01***35	Bolt,(F4320-52a0 -5 )	2
01***16	Bolt - Starting Motor Ground Cable	1

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Komatsu : Saa6d125e-3h-8m(S/N 310001-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-3h-8m(S/N 310001-Up) : Engine : Piston(#310521-)

02***13	Pin, Dowel	2
04***18	Ring, Snap	12
61***30	Bushing,(Service Part)	1
61***10	Screw	2

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Rocker Arm(#310521-)

01***75	Screw	40
01***08	Nut,R.H. Thread	12
01***32	Washer,(With Auto Emergency Steering)	40
61***10	Housing, Rocker Lever	6

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Safty Guard (For Fuel Injection Pump Drive) (For Regulation Of Epa)(#310781-)

01***20	Bolt,(For Mono Lever Steering)	1
41***70	Bracket	1
60***40	Bolt	1
61***51	Cover,Safety	1

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Safty Guard (For Fuel Injection Pump Drive)(#310522-)

01***20	Bolt,(For Mono Lever Steering)	2
61***51	Cover,Safety	1

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Safty Guard(#310521-310521)

01***20	Bolt,(For Mono Lever Steering)	2
61***50	Cover, Safety	1

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Starting Motor (11kw) (Inner Parts)(#310718-)

60***21	Starting Motor Assembly (11kw)	1
KD***40	Spring,Spring	4
KD***57	Bearing, Ball, Front	1
KD***30	Armature Assembly	1

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Starting Motor (7.5kw) (Inner Parts)(#310521-310961)

60***30	Starting Motor Ass'Y,(7.5kw)	1
KD***60	Shift Lever Assembly	1
KD***40	Spring,Spring	4
KD***67	Bearing, Ball	1

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Starting Motor Mounting (11kw)(#310718-)

01***45	Bolt,(For 60ton Dump Body)	3
01***16	Bolt - Starting Motor Ground Cable	2
01***45	Washer,(For Travel Motor) (Not Show)	3
04***10	Clip,(F4320-51a0 -8 )	1

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Starting Motor Mounting (7.5kw)(#310521-)

01***40	Bolt,(For Slag Handling) (For Usa)	2
01***45	Bolt,(For 60ton Dump Body)	1
01***16	Bolt - Starting Motor Ground Cable	2
01***45	Washer,(For Travel Motor) (Not Show)	1

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Stop Motor(#310521-)

01***30	Bolt - M14 X 30lg	3
01***16	Bolt, Mounting Transmission Control Switch	3
01***16	Bolt, Mount Solenoid Valve	2
01***20	Bolt,(Forwarded Individually Parts)	2

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Tachometer Drive

01***75	Screw	2
01***32	Washer,(With Auto Emergency Steering)	2
61***32	Gear, Tachometer	1

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Thermostat And Thermostat Housing

01***65	Bolt, Mount Tube To Divider Valve	4
02***04	Plug,(For Shipping)	1
60***30	Thermostat	1
61***90	Gasket (K2?K6)	1

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Turbocharger And Oil Piping(#310521-)

01***90	Bolt	2
01***45	Screw	4
01***20	Bolt,(Forwarded Individually Parts)	2
01***30	Bolt,(Water Separator Spec.)	2

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Water Drain Valve

07***25	Clip,(For Slag Handling)	1
07***75	Hose	1
61***12	Valve,Water Drain	1
61***10	Clip	1

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Water Pump Gasket Kit(#310521-)

02***37	O-Ring,(For Pc750?1800) (A5010)	1
07***15	O-Ring,(F4320-57a0 -11 )	1
61***10	Seal,Water (K6)	1
61***21	Gasket (K6)	3

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Water Pump(#310521-)

01***16	Bolt - Seat And Tether Belt Mounting	6
01***20	Bolt, Hose Clamps (Inlet And Return Line Hoses)	2
01***30	Bolt - Lower Oil Cooler Outlet Tubemounting	1
01***35	Bolt, Mount Bracket To Floor	2

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Komatsu : Saa6d125e-3h-8m(S/N 310001-Up) : Engine : Water Temperature Sensor(#310521-)

01***30	Bolt - Lower Oil Cooler Outlet Tubemounting	1
01***65	Bolt, Mount Tube To Divider Valve	1
07***15	Plug,(Used When Without Heater)	2
08***10	Bracket, Bucket Position Sensor	2

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SAA6D125E-3H-8M(S/N 310001-UP) serial number reference

The PIN plate for Komatsu machines exported to regulated markets (US/EU) since approx. 2003 is a 17-character ISO PIN located on the EPA/Emissions plate, typically riveted near the engine bay or behind the cab. For the SAA6D125E-3H-8M engine, the engine serial number (starting at 310001) is stamped on the engine block, usually on the left side near the injection pump. The machine's chassis serial number is found on the right-hand side of the cab on the lower frame (excavators) or front frame (dozers/loaders).

Prefix	Identifies	Notes
SAA6D125E-3H-8M	Engine Model	Identifies the specific engine configuration for the serial range 310001-UP. This engine is used in Komatsu PC400-7 and PC450-7 excavators. Note: Some sources list 'SAA6D125E-3' generally for this serial range; the 'H-8M' suffix specifies the exact variant for this range. Verify with dealer for exact configuration match.
SA6D125E-3B-7/8	Engine Model (Related)	Listed alongside SAA6D125E-3 (310001-Up) by DK Engine Parts as part of the 125 Series. Likely a related variant or earlier/later serial break for the same engine family. Cross-reference with dealer to confirm if this prefix applies to the 310001-UP range or a different one.

Frequently asked questions

What is the engine specification for the Komatsu SAA6D125E-3H-8M?

The SAA6D125E-3H-8M is a 6-cylinder, 11.0-liter (11.04 L) diesel engine producing 345 to 347 hp at 1,900 rpm. It features variable geometry turbocharging, air-to-air aftercooling, and a Bosch-style fuel injection system. It is a Tier 3/Stage IIIA compliant engine used in the PC400-7 and PC450-7 excavators.

What is the operating weight of the machines powered by this engine?

The operating weight varies by configuration and attachment package. For the PC400-7 and PC450-7 series excavators, the weight typically ranges from 39,000 to 45,000 lb (17,700 to 20,400 kg). Specific weights depend on the boom, stick, counterweight, and undercarriage setup.

What engine replaced the SAA6D125E-3H-8M?

The SAA6D125E-3H-8M was replaced by the SAA6D125E-5 engine in the subsequent dash-8 generation of Komatsu excavators (PC400-8/PC450-8). The SAA6D125E-5 is a Tier 4 Interim/Stage IIIB compliant engine that succeeded the dash-7 series in the Komatsu lineup.

What SAA6D125E-3H-8M(S/N 310001-UP) owners discuss

What are the known powertrain and hydraulic behaviors for the Komatsu SAA6D125E-3H-8M engine series?

The SAA6D125E-3H-8M is a 6-cylinder, 11.0-liter diesel engine producing 347 hp at 1850 rpm. It utilizes a Bosch-style fuel system with injectors operating at 3,200 PSI. The engine is turbocharged with an air-to-air aftercooler (CAC). It is commonly found in Komatsu PC400LC-7 and PC450-7 excavators. The powertrain is designed for heavy-duty applications, with a displacement of 11.04 liters (674 in³). The engine block features hardened liners and high-alloy piston rings, distinguishing it from earlier naturally aspirated variants. The hydraulic system in machines equipped with this engine typically requires specific flow settings that differ from Cummins-powered equivalents. The engine is Tier 2 emissions compliant and includes an ECM for emissions control, DDI (Direct Digital Injection), and TC (Turbocharging) management. The engine's design prioritizes durability in mass excavation and trenching tasks, with a focus on maintaining low-side fuel pump pressure under load to prevent performance degradation.

What undercarriage or wear patterns are typical for machines powered by the SAA6D125E-3H-8M engine?

Machines equipped with the SAA6D125E-3H-8M engine, such as the PC400 and PC450 series excavators, typically operate in the 40-ton class. These machines often feature long-carriage (LC) undercarriages for stability during heavy digging. Wear patterns commonly include accelerated track shoe wear in abrasive conditions, idler and sprocket wear due to high torque loads, and undercarriage component fatigue from heavy lifting operations. The operating weight of these machines ranges from approximately 38,000 to 42,000 lbs (17,200 to 19,000 kg), depending on the configuration. Bucket capacities typically range from 1.5 to 2.5 cubic meters (1.96 to 3.27 cubic yards). Undercarriage life is influenced by ground conditions, track tension, and operator technique. Regular inspection of track links, rollers, and idlers is recommended to prevent premature failure. The machine's weight distribution and hydraulic force capabilities require robust undercarriage components to handle the stresses of continuous heavy work.

What are the specific quirks of the SAA6D125E-3H-8M engine per its series?

The SAA6D125E-3H-8M engine series is known for its robust construction and high torque output. A notable quirk is the sensitivity of the low-side fuel pump to pressure drops under load, which can cause poor performance if the pump drive gear key fails or wears. The engine uses a Bosch-style fuel injection system with high-pressure injectors (3,200 PSI), requiring precise calibration. The engine is equipped with an ECM that manages emissions and performance, which can trigger derates if soot levels become excessive in later variants, though the SAA6D125E-3H-8M is Tier 2 and does not have a DPF. The engine's cooling system is water-cooled, and the turbocharger is variable geometry. The engine's design includes a single head with hardened liners, which contributes to its durability but requires careful monitoring of oil pressure to prevent bearing wear. The engine's performance is optimized for heavy-duty applications, with a focus on reliability and fuel efficiency.

What are common electrical or sensor issues associated with this engine?

Common electrical and sensor issues include failures in the oil pressure sensor, which can lead to incorrect gauge readings and potential engine damage if not addressed. The ECM may trigger fault codes related to sensor malfunctions, such as temperature or fuel pressure sensors. The engine's electrical system is sensitive to voltage fluctuations, which can affect the ECM's performance. Fault codes such as E10 (engine controller power failure) and E11 (engine control failure) are indicative of electrical issues. The engine's wiring harness may suffer from wear or damage, leading to intermittent faults. Regular inspection of electrical connections and sensors is recommended to prevent unexpected failures. The engine's ECM is programmed to protect the engine by reducing output power in case of detected faults, which can impact machine performance.

What should be checked when buying a used SAA6D125E-3H-8M engine?

When buying a used SAA6D125E-3H-8M engine, verify the serial number matches the S/N 310001-UP range to ensure correct parts compatibility. Check the engine's compression ratio and oil pressure to assess internal wear. Inspect the fuel pump for wear, particularly the drive gear key, which is a known failure point. Examine the turbocharger for shaft play and blade damage. Check the condition of the injectors and fuel lines for leaks or wear. Verify the engine's cooling system for leaks and corrosion. Inspect the engine's mounting points and frame for cracks or damage. Check the engine's electrical connections and sensors for corrosion or damage. Verify the engine's history, including maintenance records and any previous repairs. Ensure the engine is compatible with the intended machine model, such as the PC400LC-7 or PC450-7. Have your dealer verify the engine's condition and compatibility before purchase.

What are the recommended fluid specifications for the SAA6D125E-3H-8M engine?

The SAA6D125E-3H-8M engine requires Komatsu Genuine Oil for optimal performance. Diesel engine oil should meet Komatsu Engineering Standards. Hydraulic oil should be Komatsu Genuine Hydraulic Oil. Axle oil and powertrain oil should also be Komatsu Genuine. Coolant should be Komatsu Super Coolant AF-NAC. The engine's oil capacity varies by configuration, but typically requires approximately 30 liters (7.93 gallons) of oil. The cooling system capacity is approximately 20 liters (5.28 gallons). Always consult the operation and maintenance manual for the specific machine for exact capacities and specifications. Using non-genuine fluids may void warranties and reduce engine life.

What are the service intervals for the SAA6D125E-3H-8M engine?

Service intervals for the SAA6D125E-3H-8M engine vary by operating conditions and usage. Typically, the engine oil and filter should be changed every 500 hours. The fuel filter should be changed every 500 hours. The air filter should be inspected every 250 hours and replaced as needed. The hydraulic oil filter should be changed every 1000 hours. The coolant should be changed every 2000 hours. The turbocharger and injectors should be inspected every 1000 hours. Regular maintenance is essential to ensure the engine's longevity and performance. Always consult the operation and maintenance manual for the specific machine for exact service intervals and procedures.

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

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