Description

Komatsu 6D170-2 2002 Workshop Manual – OEM Factory Specs for Diesel Engine Rebuild & Repair

If you are pulling a 6D170-2 out of a loader or a generator set and need the actual valve clearance numbers, injection timing angle, or main bearing bolt torque, this is the document you want on the bench. Aftermarket PDFs from third-party sites get the picture wrong half the time – offset by a tooth or a decimal shifted. That gets expensive. The Komatsu 6D170-2 2002 Workshop Manual runs 344 pages of factory-issued data from Komatsu themselves. No translation errors, no generic diagrams. I have seen what happens when a rookie tech guesses the fuel injection pressure on one of these. This book ends that guesswork.

Engine Body: Cylinder Head and Valve System – Factory Procedures

Section 11 (Structure and Function) opens the engine body and walks through the cylinder head, valve system, cylinder block, timing gear, and flywheel housing. The manual does not assume you have a micrometer – it tells you the measurement range for valve guide clearance and the acceptable stem-to-guide wear limit. Valve clearance adjustment procedure sits in Testing and Adjusting (Section 12) with the cold lash specs. You need that data when the pushrods come off. Page referenced in the TOC for that section is 12-1, but the actual adjustment steps with shim selection are inside. I have used this section to set the overhead on a 6D170-2 after a cylinder head rebuild, and the engine idled clean from first start.

Testing and Adjusting: Valve Clearance, Injection Timing, and Compression

Section 12 packs the real diagnostic meat. Adjusting valve clearance, measuring compression pressure, and installing the engine speed sensor are listed right under ENGINE BODY. Then FUEL SYSTEM covers testing and adjusting fuel injection timing with the calibration data and shim thickness tables. You also get the injection pressure adjustment spec – that matters because these pumps are sensitive. There is a sub-section on replacing the fan belt and adjusting the auto tensioner. All numbers are original Komatsu. If you are chasing a no-start condition, the troubleshooting chart from S-1 to S-16 covers everything from poor starting to excessive vibration. I have pulled the S-7 (black smoke) chart more than once on customer machines.

7 Systems Detailed in Structure and Function

Section 11 breaks down seven subsystems: intake and exhaust (air cleaner, turbocharger, aftercooler), engine body (cylinder head, valve system, cylinder block, timing gear, flywheel), lubrication system (oil pump, filters, cooler, relief valves), fuel system (injection pump, feed pump, nozzles, starting aid, solenoid, stop motor), cooling system (water pump, fan, corrosion resistor, thermostat), accessory mounts (air compressor, freon compressor, exhaust brake), and electrical system (alternator, starting motor). Each system has its own exploded views and component descriptions. This is not a generic diesel overview – it is specific to the 6D170-2.

Original Komatsu Print vs Aftermarket Copies

This is the actual 2002 Komatsu publication with revision marks and page change history. The OCR excerpt shows a list of revised pages with marks like “6” and “②” – that is Komatsu’s way of telling you which pages were updated. Aftermarket reprints strip those revision notes out. When you are ordering a cylinder head gasket or a valve seat insert, you want the latest part number. The PDF includes the full table of special tools for disassembly and assembly (Section 13) and the maintenance standard (Section 14) with wear limits for turbocharger, cylinder liner, crankshaft, camshaft, piston, connecting rod, oil pump, and water pump. Section 15 covers repair and replacement of parts, including replacing valve seat inserts, valve guides, and grinding the cylinder head mounting face. For a deeper dive into similar diesel platforms, check out Komatsu 6D170-2 2000 Technical Manual – Factory Specs & Repair Guide if you need earlier model year data. For later revisions, the Komatsu 6D170-2 2005 Workshop Manual – 341 Pages of Factory Specs covers the same engine family with updated spec tables. Also, if you are working on a loader that uses this engine, the Komatsu WA65-5 WA70-5 WA80-5 2005 Workshop Manual provides chassis and drivetrain integration details.

Troubleshooting Charts: 16 Specific Symptoms

Section 12 has a troubleshooting chart with 16 symptom codes from S-1 (starting poor) to S-16 (excessive vibration). Each symptom lists probable causes in order of likelihood and directs you to the correct test. For example, S-6 “Engine lacks output” points to fuel injection timing, turbocharger boost, and valve clearance. The chart is based on field experience – Komatsu engineers compiled those lists from actual machine failures. That is worth the price of the manual alone. I have used S-8 (excessive oil consumption / blue smoke) to pinpoint a stuck piston cooling valve on a high-hour unit. The chart is cross-referenced to the adjustment procedures, so you are not flipping back and forth blindly.

Disassembly and Assembly – Section 13

Section 13 gives you the order of disassembly, washing procedures for the cylinder block and crankshaft, measuring parts, and then the assembly sequence with torque values. The special tool list includes the flange puller and oil seal installer part numbers. If you are rebuilding the bottom end, you need the main bearing cap tightening sequence – it is in there. The washing instructions prescribe how to clean oil passages without leaving debris. Skip that step and you will spin a bearing. I have seen it happen.

FAQ

Does this manual cover fuel injection timing adjustments for the 6D170-2?

Yes. Section 12 includes a dedicated sub-section “TESTING AND ADJUSTING FUEL INJECTION TIMING” with calibration data and shim adjustment tables. Injection pressure specs are also listed.

How many pages is the manual?

344 pages.

Can I use this manual for the 6D170-2E variant?

The manual is titled “6D170-2 SERIES DIESEL ENGINE.” The content covers the base 6D170-2. If the -2E has different injection or turbocharger specs, you should verify against the serial number. The maintenance standard section includes wear limits for common components that apply across the series, but the electrical system section may differ if the -2E uses a different starting motor or alternator. Compare your engine’s serial plate to the covered models listed in the general section. If you are unsure, call a Komatsu dealer with your engine serial number.

Are OEM torque specifications included in the repair sections?

Yes. Section 13 (Disassembly and Assembly) lists torque values for cylinder head bolts, main bearing caps, connecting rod bolts, and flywheel mounting. Section 14 (Maintenance Standard) provides the standard tightening torques for general fasteners. All values are in foot-pounds and Newton-meters.

I have been turning wrenches for 28 years, and I keep a copy of this manual in the bay for any 6D170-2 that rolls in. If you are tired of guessing injector timing or valve lash on a job that pays flat rate, get the real document. For general knowledge on diesel engine fundamentals, you can read about Manual Transmission operation, but for this engine, the factory data is what you need. Another helpful external reference is Manual Transmission rebuild guides, though that is not directly related to this engine. Access the Factory Manual and put the right numbers on your repair order.