Komatsu 125E-5 Series Engine Shop Manual SEN00177-16 – SAA6D125E-5 Diesel Repair PDF

Description

Komatsu 125E-5 Series Engine Shop Manual – SEN00177-16

This is the complete Komatsu 125E-5 Series Engine Shop Manual, published under document number SEN00177-16. It covers the SAA6D125E-5 in-line 6-cylinder, water-cooled, common rail direct injection, 4-stroke diesel engine used across Komatsu construction, mining, and industrial machinery. The same manual is used for both the with EGR and EGR-less configurations, and the text clearly distinguishes the two throughout.

Rather than a quick-reference sheet, this is the full workshop document: engine specifications, structure and function descriptions, maintenance standards, a standard value table, testing and adjusting procedures, electrical and mechanical troubleshooting with code tables, complete disassembly and assembly instructions, and detailed repair and replacement of cylinder head and cylinder block parts.

File Details

• Manual type: Engine Shop Manual (workshop / service)
• Brand: Komatsu
• Engine: SAA6D125E-5
• Document number: SEN00177-16
• Language: English
• Format: PDF
• Page count: Approx. 650 pages
• Publication date shown: 03-17 (01)

Chapters Covered

• 00 Index and foreword
• 01 Specification
• 10 Structure, function and maintenance standard
• 20 Standard value table
• 30 Testing and adjusting
• 40 Troubleshooting
• 50 Disassembly and assembly
• 90 Repair and replacement of parts

00 – Index and Foreword

Safety notice, how to read the shop manual, explanation of terms for maintenance standard, handling of electric equipment and hydraulic components, handling of the connectors newly used for engines, how to read electric wire code, precautions when carrying out operation, method of disassembling and connecting push-pull type couplers, standard tightening torque table, and conversion tables. This is where the working conventions for the rest of the manual are set — units (SI with gravitational equivalents in braces), standard size and tolerance notation, standard clearance, standard interference, repair limit, clearance limit, and interference limit.

01 – Specification

Applicable machine and engine serial number table, outline of the engine (with EGR and EGR-less), full specifications per machine application, general view illustrations from front, rear, left, right, and top, a dimensions table, weight table with component-by-component values, and engine performance curves (torque and flywheel horsepower vs. engine speed).

10 – Structure, Function and Maintenance Standard (Part 1 and Part 2)

Part 1 covers general structure, air intake and exhaust, air cleaner, turbocharger, aftercooler, EGR system, cylinder head, cylinder block, cylinder liner, main moving parts, crankshaft, camshaft, cam follower and push rod, piston, piston ring and piston pin, connecting rod, flywheel and flywheel housing, vibration damper, timing gear, valve system, valve and valve guide, rocker arm and shaft, and crosshead and guide. Part 2 covers the lubrication system and diagram, main relief valve, EGR oil pump, oil filter, safety valve, oil cooler, fuel system and CRI system diagram, outline of the CRI system, fuel piping, fuel filter, electric priming pump, engine controller cooler, cooling system and diagram, water pump, thermostat, and electrical equipment including alternator, starting motor, electrical intake air heater, and engine controller.

20 – Standard Value Table

Standard service value tables for testing, adjusting, and troubleshooting, organized by machine model, with measurement conditions, standard values for new machines, and judgement criteria. Also includes the running-in standard and performance test standard tables.

30 – Testing and Adjusting

Split into with-EGR and EGR-less sections. Tools lists and sketches, testing air boost pressure, testing exhaust temperature, adjusting valve clearance, testing compression pressure, testing blow-by pressure, testing engine oil pressure, measuring EGR valve and bypass valve drive pressure, handling fuel system parts, releasing residual pressure, testing fuel pressure, reduced cylinder mode operation, no-injection cranking, testing leakage from the pressure limiter and return rate from the injector, bleeding air from the fuel circuit, testing the fuel system for leakage, adjusting the speed sensor, testing and adjusting alternator belt tension, and handling the controller voltage circuit.

40 – Troubleshooting

General information and points on troubleshooting, an error code and failure code table, and information on how the troubleshooting tables are structured. The electrical system (E-mode) troubleshooting is split into two parts covering the full E-code range, from ECM critical internal failure and Ne/Bkup speed sensor errors through charge air pressure, throttle, oil pressure, coolant temperature, charge air temperature, sensor supply, injector open/short codes, rail pressure codes, EGR and bypass valve servo errors, KOMNET datalink timeout, and oil pressure/overheat derate codes. The mechanical system (S-mode) troubleshooting covers starting performance, engine not starting, pick-up, stalling during operation, rough running, lack of output, black exhaust smoke, oil consumption, oil contamination, fuel consumption, oil in coolant, oil pressure drops, oil level rising, overheating, abnormal noise, and vibration.

50 – Disassembly and Assembly

General information, coating materials list, special tools list, general disassembly and assembly of the engine (Part 1 with EGR, Part 2 EGR-less), and Part 3 covering removal and installation of the fuel supply pump unit and replacement of the oil seal of the engine mounted on the machine. Torque values, coating materials, and oil/coolant quantities are provided in the procedure steps.

90 – Repair and Replacement of Parts

Flowchart, special tool table and sketches, parts related to the cylinder head (part names, testing and inspection, pressure test, replacement of valve guide, valve seat insert, crosshead guide, valve grinding), and parts related to the cylinder block (part names, testing and inspection, crankshaft, connecting rod, replacement of flywheel ring gear, camshaft gear, main bearing metal cap, connecting rod small end bushing, cam bushing, engine rear seal, wear sleeve, and repair of crankshaft by grinding).

Why This Komatsu 125E-5 Engine Manual Belongs in Your Workshop

The SAA6D125E-5 is a high-pressure common rail engine with a hydraulically driven, electronically controlled EGR system on the with-EGR variants. That means the repair decisions that actually matter — injector diagnostics, rail pressure diagnosis, PCV1/PCV2 fault isolation, EGR valve and bypass valve servo checks, and the fuel-delivery timing of the high-pressure pump — all depend on having the manufacturer’s own procedures, tolerances, and code tables in front of you. This manual supplies them.

With roughly 650 pages of testing values, code-driven diagnostics, torque tables, and step-by-step disassembly and assembly, this manual supports the full range of work: routine valve clearance and belt adjustment, compression and blow-by testing, fuel pressure testing, pressure limiter and injector return-rate checks, cylinder head and cylinder block repair, crankshaft inspection and grinding limits, and complete engine teardown and rebuild. The standard value table gives you the numbers to judge whether a component is within new-machine spec or past its repair limit, and the troubleshooting section walks you through the E-mode and S-mode symptom chains rather than guessing at parts.

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Delivered as an instant-download PDF after checkout — no shipping, no waiting. Read it on a laptop, tablet, or phone in the workshop, or print the pages you need for the job at hand. Keep the file on the shop computer and you have the Komatsu 125E-5 Series engine documentation available whenever the next SAA6D125E-5 comes in for service.