Komatsu 125-3 Series Engine Shop Manual – SAA6D125E-3 & SA6D125E-3 PDF

Description

Komatsu 125-3 Series Diesel Engine Shop Manual — Document SEBM024207

This is the full workshop reference for the Komatsu 125-3 Series diesel engine, published under document number SEBM024207. It covers both engine specifications built on the 125 platform: the SAA6D125E-3 (in-line fuel injection pump and common rail variants) and the SA6D125E-3 common rail variant used in bulldozer applications. The manual is written for service technicians working in a workshop environment and assumes the engine is on a stand or in the machine with normal shop tooling available.

File Details

• Manual type: Engine Shop Manual (Service, Testing & Repair)
• Brand: Komatsu
• Engine series: 125-3 Series (SA6D125E-3 / SAA6D125E-3)
• Document number: SEBM024207
• Language: English
• File format: PDF
• Page count: 340+ pages
• Configuration: In-line, 6-cylinder, water-cooled, direct injection, 4-cycle diesel
• Bore x stroke: 125 x 150 mm
• Displacement: 11.0 L {11,040 cc}
• Firing order: 1-5-3-6-2-4

Machines Covered by This Engine Manual

• WA430-5 Wheel Loader
• WA470-5 Wheel Loader
• WA480-5 Wheel Loader
• D65EX-15 / D65PX-15 Bulldozer
• D85EX-15 / D85PX-15 Bulldozer
• HM300-1 Articulated Dump Truck
• PC400-7 Hydraulic Excavator
• PC450-7 Hydraulic Excavator

Chapters Covered

• 01 GENERAL
• 11 STRUCTURE AND FUNCTION, MAINTENANCE STANDARD
• 12 TESTING AND ADJUSTING
• 13 DISASSEMBLY AND ASSEMBLY
• 15 REPAIR AND REPLACEMENT OF PARTS

01 GENERAL

Opens with the applicable-machine table that pairs each engine variant to its machine model, followed by an outline of the 125E-3 engine design and its emissions compliance. Full engine specifications are listed for both the in-line fuel injection pump specification and the common rail system specification, including rated horsepower, maximum torque, idling speeds, fuel consumption, oil and coolant capacities, alternator and starting motor ratings, and dry weights. General assembly drawings are provided for both the left and right side views and the front and rear views. Dimension tables, a component weight table and engine performance curves complete the chapter.

11 STRUCTURE AND FUNCTION, MAINTENANCE STANDARD

Explains how each major assembly is built and how it works, with a maintenance standard table attached to each component. It covers the intake and exhaust system (air cleaner, turbocharger, aftercooler), the engine body (cylinder head, cylinder block, cylinder liner, main circulation system, crankshaft, piston, connecting rod, flywheel and housing, vibration damper, timing gear, valve mechanism, camshaft, cam follower and push rod, valve and valve guide, rocker arm shaft, crosshead), the lubrication system with its circuit diagram, the fuel system with the CRI (Common Rail Injection) outline, fuel piping, fuel cooler and fuel filter, the cooling system chart with water pump, thermostat and corrosion resistor, and the electrical system including alternator and starting motor.

12 TESTING AND ADJUSTING

Contains the testing and adjusting data tables for both engine specifications, the standard value table for electrical parts, a full testing and adjusting tool list, and step-by-step procedures for measuring intake air pressure (boost pressure), exhaust temperature, valve clearance, compression pressure, blow-by pressure, engine oil pressure and fuel pressure. The fuel injection timing procedure is included for the in-line pump specification, along with air bleeding, fuel system leak checking, handling of the common rail high-pressure circuit, and the reduced cylinder mode operation method. Engine system troubleshooting (S mode, S-1 through S-16) and electrical system troubleshooting (E mode, E-1 through E-36) are given as diagnostic matrices and error-code procedures covering all sensors, PCV valves, injectors and controller circuits.

13 DISASSEMBLY AND ASSEMBLY

Provides the general disassembly sequence from starting motor and turbocharger down to crankshaft and cylinder liner, followed by the general assembly sequence in the reverse direction. Each step carries its own tightening torque, coating material, and assembly precaution. Special notes cover the plastic range turning angle method used on the cylinder head bolts, main cap bolts and connecting rod cap bolts, including stem length limits and reuse rules. Detailed sub-procedures are given for piston ring installation, piston protrusion measurement, liner O-ring and clevis seal installation, crankshaft end play, and flywheel and damper runout checks.

15 REPAIR AND REPLACEMENT OF PARTS

Dedicated to reconditioning work on the cylinder head and cylinder block. Cylinder head coverage includes replacing valve seat inserts, nozzle holder sleeves, valve guides and crosshead guides, plus valve grinding, fitting-face grinding and pressure testing. Cylinder block coverage includes replacing cam bushings, cam gear, flywheel ring gear, engine rear seal, connecting rod small end bushing and main bearing caps, with a full crankshaft grinding procedure covering inspection, hardness checks, fillet measurement, etching inspection, magnetic flaw detection, undersize marking and finishing specifications.

Why This Komatsu 125-3 Series Shop Manual Belongs in Your Workshop

The 125-3 Series engine sits behind some of the hardest-working machines in the Komatsu line, and the electronic common rail fuel system on this generation is not something you can diagnose or repair by feel. The SAA6D125E-3 and SA6D125E-3 service data in this manual give you the exact compression pressures, oil pressures, valve clearances, torque sequences, stem length limits, injector resistance values and error code descriptions you need to make a correct call the first time. Rather than guessing at a PCV fault, a low-pressure fuel issue or a dropped oil pressure reading, you can work straight from the E-mode troubleshooting charts and the standard value tables that go with them.

Because this is the same manual Komatsu service workshops used, the procedures are laid out the way a technician actually works: component by component, with a structure explanation, a maintenance standard, a testing and adjusting procedure, and a disassembly and assembly sequence for each major assembly. For anyone rebuilding a 125E-3 engine, the cylinder head and cylinder block repair chapter alone is worth having — it includes press-fit dimensions, oversize insert tables, sleeve rolling dimensions, crankshaft undersize marking, fillet R measurement and the plastic range turning angle method for the cylinder head bolts, main cap bolts and connecting rod cap bolts.

IMAGES PREVIEW

You receive the complete Komatsu 125-3 Series engine shop manual as an instant PDF download after checkout. No shipping, no waiting for a disk. The file opens on any laptop, tablet or phone, prints cleanly in full size for the workshop bench, and can be kept on your shop PC for future reference. Whether you are servicing a single D65EX dozer, running a fleet of WA470-5 loaders, or rebuilding an HM300-1 engine on the stand, this manual is the reference document to keep within reach.