Mitsubishi S12R Diesel Engine Service Manual (tp6854)

These S12R engines usually sit in generators or heavy industrial equipment that run hard in hot, dusty, or salty environments. This service manual is what I’d keep open when I need to trace a running issue or tear into the engine without guessing. For example, if the unit starts hunting under load, I’d use this book to step through checks on fuel, air, and timing before I condemn an injector pump or start pulling heads.

Applications & Use Cases

Walk through system flow diagrams to isolate whether a fault is fuel, air, cooling, or lubrication related.
Follow the diagnostic logic to verify a suspected failure before ordering expensive parts.
Use the disassembly/assembly sequences to strip and rebuild components in the right order and avoid missed seals or misaligned gears.
Confirm adjustment procedures for things like linkages and clearances so the engine comes back on line cleanly after repairs.
Cross-check component layouts when routing hoses, pipes, and harnesses after major work.

FAQ

Q: Can I use this on a tablet in the field?

A: Yes, it’s practical on a tablet or laptop; you can zoom diagrams and search text when you’re at the genset.

Q: Is it worth printing parts of it?

A: I’d print the procedures I use often, mark them up with notes, and keep them in a binder near the unit.

Safety Note

Always lock out the starter circuit and verify the engine cannot crank before opening any system.

📘 Show Index

Mitsubishi S12R Diesel Index:

Chapter 1 GENERAL
1. External view
2. System flow diagrams
3. Content of plate and label
4. Main specifications
Chapter 2 SERVICE DATA
1. Maintenance service data
2. Tightening torque table
Chapter 3 SERVICE TOOLS
1. Special tools
Chapter 4 OVERHAUL INSTRUCTIONS
1. Determining overhaul timing
2. Compression pressure – Measure
Chapter 5 DISASSEMBLY OF BASIC ENGINE
1. Cylinder heads and valve mechanisms – Disassemble and inspect
2. Rear mechanism – Disassemble and inspect
3. Front mechanism – Disassemble and inspect
4. Cylinder liner, piston and connecting rod – Disassemble and inspect
5. Crankcase, crankshaft and main bearing – Disassemble and inspect
Chapter 6 INSPECTION AND REPAIR OF BASIC ENGINE
1. Cylinder head and valve mechanism – Inspect and repair
2. Rear mechanism – Inspect and repair
3. Front mechanism – Inspect and repair
4. Piston and connecting rod – Inspect and repair
5. Crankcase and crankshaft – Inspect and repair
Chapter 7 ASSEMBLY OF BASIC ENGINE
1. Crankshaft and main bearing – Install
2. Cylinder liner, piston and connecting rod – Assemble
3. Front mechanism – Assemble
4. Rear mechanism – Assemble
5. Cylinder head and valve mechanism – Assemble
Chapter 8 FUEL SYSTEM
1. Fuel system – Remove and inspect
2. Fuel system – Disassemble and inspect
3. Fuel system – Install
Chapter 9 LUBRICATION SYSTEM
1. Lubrication system – Remove and inspect
2. Lubrication system – Disassemble, inspect and assemble
3. Lubrication system – Install
Chapter 10 COOLING SYSTEM
1. Cooling system – Remove and inspect
2. Cooling system – Disassemble, inspect and assemble
3. Cooling system – Install
Chapter 11 INLET AND EXHAUST SYSTEMS
1. Inlet and exhaust systems – Remove and inspect
2. Inlet and exhaust systems – Disassemble, inspect and assemble
3. Inlet and exhaust systems – Install
Chapter 12 AIR START SYSTEM
1. Air start system – Remove
2. Air start system – Disassemble, inspect and assemble
3. Air start system – Install
Chapter 13 ADJUSTMENT AND OPERATION
1. Engine – Adjust
2. Break-in operation
3. Engine-Test and adjustment