Description

Komatsu PC650-3, PC650LC-3, PC650SE-3 1991 Workshop Manual

If you’re pulling the cylinder head on a PC650-3 without the factory numbers, you’re betting the work. I’ve seen too many guys guess on torque specs and end up with a warped deck or a blown head gasket a week later. The Komatsu PC650-3, PC650LC-3, PC650SE-3 1991 Workshop Manual ends that guessing. This is the same 801-page binder that Komatsu issued to dealer techs. Not a reprint, not a scan of a scan — original OEM file from 1991.

Komatsu PC650-3, PC650LC-3, PC650SE-3 Workshop Manual: Engine Section

The engine section alone runs nearly 100 pages. Section 12 covers testing and adjusting. Need the valve clearance spec? Page 12-6 has the procedure with the exact feeler gauge size and tightening order. Fuel injection timing? The manual shows static timing mark alignment with the flywheel. The auto-deceleration system (if equipped) has its own adjustment procedure — don’t skip it.

Disassembly and Assembly of the Cylinder Head and Turbocharger

Section 13 walks you through removing and installing the cylinder head, turbocharger, nozzle holder, water pump, and more. Each procedure starts with a tool list. The water pump puller? They list the Komatsu part number and a generic equivalent. The torque sequence for the head bolts is on page 13-28. I’ve seen aftermarket manuals skip the tightening pattern — this one has a diagram. Follow it.

Power Train: Travel Motor and Swing System Disassembly

The power train section (20) is massive. Section 23 covers disassembly and assembly of the travel motors, swing pump, center swivel joint, final drive. The manual includes hydraulic circuit schematics in section 21 — you’ll see the straight-travel system circuit and the swing brake system. Rebuilding a travel motor? The manual gives clearance specs for the valve plate and plunger. Page 24-4 has the maintenance standard for travel motor tolerances. Don’t try to wing it.

Why OEM Documentation Matters Over Aftermarket Copies

Aftermarket manuals pull data from who knows where. They miss revision marks. Notice the List of Revised Pages in the front of this manual — pages 00-3 to 00-13 show every change made during production. That’s something a third-party publisher won’t include. This manual has the exact serial number range: PC650-3 10501 and up. If your machine falls in that range, these specs are correct for your engine SA6D140-1. The manual also includes the revision history with marks (●) indicating which pages were added or replaced. This level of traceability saves you from using outdated torque values or clearance specs that could cause failure. I’ve seen a guy use a 1990 spec on a 1991 machine and snap a bolt. Don’t let that be you.

Fuel System and Hydraulic System Coverage

Fuel system isn’t its own section, but it’s covered inside Engine (10) and Hydraulic System (60). The fuel injection pump removal and installation is in section 13. The nozzle holder removal is also there. For hydraulic testing, section 62 has the testing and adjusting procedures. You get the test tool list, the pressure readings, and the adjustment sequence for the main relief valve on the swing control valve.

Keep in mind, the manual also covers the air system (section 50) and electric/electronic system (section 80). Those sections are thinner but contain wiring diagrams and component locations you won’t find in generic guides.

If you work on heavy Komatsu equipment, you already know the difference between factory data and a reprint. This manual is the real thing — no missing pages, no blurry diagrams, no guesswork.

Related Manuals

• Komatsu WA65-5 WA70-5 WA80-5 2005 Workshop Manual
• Komatsu WH609-1E0 WH613-1E0 WH713-1E0 WH714H-1E0 WH716-1E0 Workshop Manual
• Komatsu PW95R-2 Workshop Manual – 520 Pages of Factory Specs

For more on how manual transmissions work in heavy equipment, see Manual Transmission and Manual Transmission on YouTube.

Does this manual cover the PC650SE-3 with the auto-deceleration system?

Yes.

What torque values are listed for the cylinder head?

The manual provides the tightening sequence and torque values on page 13-28. You get the step torque values in ft-lbs and the final angle for each bolt. It also lists the oil cooler, turbocharger, and water pump torque specs separately. If you mix up the tightening pattern, you can warp the head. Without this factory data, you risk stripping threads, causing oil leaks, or blowing a head gasket. I’ve seen guys use generic specs and ruin a $2,000 head rebuild. Don’t be that guy.

Stop risking your machine and your wallet. Access the Factory Manual and get the exact specs Komatsu put on the line.