Ring gaps, gear backlash and nozzle settings that no parts catalogue prints are settled in this 147-page Mitsubishi S4E service manual PDF, which covers the diesel engine across five designations including the 4DQ5 and S4E2. Separate chapters take the cylinder head, sleeves and pistons, timing gears, crankcase, lubrication, cooling and fuel injection system through disassembly, inspection and repair, and the electrical section carries wiring diagrams for your starter, alternator and glow plug circuits. Service data fills the back of the book with tightening torques, sealant application points and a troubleshooting chart that walks symptoms back to causes. Set piston ring gap at 0.30 to 0.50 mm, and on the 4DQ5 hold timing gear backlash between 0.12 and 0.24 mm. One tight ring gap can wreck a fresh overhaul. Bookmarked chapters and a searchable text layer let you check every clearance on the bench, so the rings and bearings you order fit the first time.
What's Inside This Mitsubishi 4DQ5, S4E, S4E2 Manual
| System | Pages | Key Topics |
|---|---|---|
| General Information | 3-25 | Exterior Views, Nomenclature and Sectional Views, Major Data and Specifications, Performance Curves, Engine Serial Number Location, Tips on Disassembly and Reassembly |
| Cylinder Head and Valve Mechanism | 26-38 | Inspection and Repair, Installation |
| Cylinder Sleeves, Pistons and Connecting Rods | 39-49 | Inspection and Repair, Reassembly |
| Flywheel and Timing Gears | 50-57 | Removal, Inspection and Repair |
| Crankcase and Major Running Parts | 58-71 | Disassembly, Inspection and Repair |
| Lubrication System | 72-77 | Oil Pump, Oil Filter, Relief Valve, Oil Strainer, Removal, Inspection and Repair |
| Cooling System | 78-83 | Removal, Inspection and Repair |
| Fuel System | 84-102 | Fuel Filter, Fuel Injection Pump, Fuel Injection Nozzles |
| Electrical System | 103-114 | Starter, Alternator, Glow Plugs |
| Overhaul Instructions | 115-119 | When to Overhaul the Engine, Bench Test |
| Special Service Tools | 120-125 | Valve Guide Installer, Valve Guide Remover, Intake Valve Insert Caulking Tool, Exhaust Valve Insert Caulking Tool, Adaptor, Piston Guide, Idler Shaft Puller, Cranking Handle |
| Service Data | 126-147 | Tightening Torque, Sealant Application Data, Troubleshooting Chart |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| Backlash | 0.12~0.24 mm (0.0047~0.0094 in) | p. 55 |
| Fuel filter element replacement interval | every 6 months or 1200 operating hours | p. 88 |
| Injection nozzle spray hole diameter | 1 mm (0.04 in.) | p. 17 |
| Fuel injection nozzle tightening torque | 5 ± 0.5 kg-m (36.2 ± 3.6 lb-ft) | p. 98 |
| Water pump impeller, vane-to-casing clearance | 0.5 ~ 1 mm (0.020 ~ 0.039 in) | p. 43 |
| Thermostat valve start opening temperature | 76.5 ± 2°C (169.7 ± 3.6°F) | p. 79 |
| Thermostat valve full open temperature | 90°C (194°F) | p. 79 |
| No. of oil rings | 1 (w/spring expander) | p. 12 |
| Piston ring gap | 0.30 ~ 0.50 mm (0.0118 ~ 0.0197 in.) | p. 44 |
| Cylinder head bolts | 12.0 ± 0.5 kg-m (86.8 ± 3.6 lb-ft) | p. 137 |
| Cylinder Head Bolt Tightening Torque | 12.0 ± 0.5 kg-m (86.8 ± 3.6 lb-ft) | p. 137 |
| Main Bearing Cap Bolts Tightening Torque (4DQ5) | 8.5 ± 0.5 kg-m (61.5 ± 3.6 lb-ft) | p. 137 |
Mitsubishi 4DQ5, S4E, S4E2 Common Problems This Manual Covers
Mitsubishi 4DQ5 S4E S4E2 fuel injection nozzle pressure too low on the nozzle tester
Test each nozzle on a nozzle tester and adjust injection pressure to 120 ± 10 kg/cm² (1706 ± 142 psi) by inserting shims, as the chart on page 145 directs. The repair limit is 110 kg/cm² (1564.2 psi) per page 101. Torque the nozzle to 5 ± 0.5 kg-m (36.2 ± 3.6 lb-ft) on reinstall.
Manual Section: Troubleshooting Chart (2) p. 145Fuel supply trouble at the engine with the fuel filter element overdue for replacement
Replace the fuel filter element every 6 months or 1200 operating hours, per the Fuel System section on page 88. If the element is overdue, change it before chasing anything else, then work through the fuel supply items in Troubleshooting Chart (2) before you pull the injection pump or nozzles.
Manual Section: Fuel System p. 88Thermostat valve opening late or not lifting fully during cooling system inspection
Test the wax thermostat against the figures on page 79: the valve should start opening at 76.5 ± 2°C (169.7 ± 3.6°F) and be fully open at 90°C (194°F). Measure valve lift at full open against 9 mm (0.35 in.) per page 80. Replace any thermostat that misses either number.
Manual Section: Cooling System p. 79Water pump impeller vane-to-casing clearance out of limit, with unit seal or shaft worn
Check water pump operation first, then pull the pump and inspect the impeller, unit seal and shaft. Measure impeller vane-to-casing clearance against 0.5 ~ 1 mm (0.020 ~ 0.039 in) as listed on page 43. Replace worn parts before the pump goes back on the engine.
Manual Section: Cooling System Inspection p. 43Piston ring end gap out of spec during cylinder sleeve and piston inspection at overhaul
Measure each piston ring gap and hold it to 0.30 ~ 0.50 mm (0.0118 ~ 0.0197 in.) per page 44. Replace rings that fall outside that range. While the pistons are out, check piston clearance and connecting rod bend, twist and end play in the same section before reassembly.
Manual Section: Cylinder Sleeves, Pistons and Connecting Rods Inspection p. 44Valve clearance out of adjustment on a cold engine during cylinder head and valve inspection
Adjust valve clearance cold to 0.25 mm (0.0098 in.) per the specifications on page 17. Inspect push rods, valve guides, seats and springs following the Cylinder Head and Valve Mechanism section from page 26. Torque cylinder head bolts to 12.0 ± 0.5 kg-m (86.8 ± 3.6 lb-ft) per page 137 on reassembly.
Manual Section: Cylinder Head and Valve Mechanism p. 17Frequently Asked Questions
What are the torque specifications for the cylinder head bolts on the Mitsubishi 4DQ5, S4E, and S4E2 engines?
The tightening torque for the cylinder head bolts on the 4DQ5, S4E, and S4E2 engines is 12.0 ± 0.5 kg-m (86.8 ± 3.6 lb-ft). p. 137
What are the fuel filter element replacement specifications for the Mitsubishi 4DQ5, S4E, S4E2 diesel engine?
The fuel filter element should be replaced after every 6 months or 1200 operating hours. p. 88
What is the specified valve clearance for the intake and exhaust valves on the Mitsubishi 4DQ5, S4E, S4E2 engines?
The valve clearance for both intake and exhaust valves is specified to be 0.25 mm (0.0098 in.) when the engine is cold. p. 38
What is the oil pressure for the 4DQ5, S4E, and S4E2 engines during duty run and at idling?
During duty run, the oil pressure should be 3 to 4 kg/cm² (42.7 to 56.9 psi). At idling, the minimum oil pressure is 1.0 kg/cm² (14.2 psi). p. 18
What is the correct procedure for bleeding air from the fuel system?
To bleed the fuel system, loosen the air plug at the top of the fuel filter, cover it with a cloth, and operate the priming pump until fuel flows without bubbles. Then, tighten the air plug and continue operating the pump until resistance is felt. p. 88
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Straight to your device: 147 pages of searchable Service Manual, downloadable the moment payment goes through.
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Zero restrictions. The PDF is DRM-free. Print whatever sections you need to take out to the shop. Standard letter or A4 paper works.
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