Wear limits, fits and tightening values for the Mitsubishi S4S and S6S diesel engines come from one source only: the 241-page factory service manual, OEM part 99616-10180, which spans four variants including the turbocharged S4S-DT and S6S-DT. As a Mitsubishi S4S, S6S service manual PDF, it puts the maintenance standards, tightening torque and sealant tables up front, then takes the cylinder head, timing gears, pistons, rods and crankshaft through disassembly, inspection and reassembly. Fuel injection pump and nozzle work follows, then the turbocharger, electrical tests for the starter, alternator and glow plugs, and the break-in and performance tests that confirm your rebuild. Check swirl-chamber compression against 3.23 MPa (469 psi) and set valve lash at 0.25 mm cold. Bookmarked and text-searchable, the PDF goes wherever the engine does, keeping your clearances in reach before it goes back together.
What's Inside This Mitsubishi S4S, S6S Manual
| System | Pages | Key Topics |
|---|---|---|
| Safety Cautions | 6-13 | Danger of Fire and Explosion, Danger of Entanglement, Danger of Burns |
| General | 14-47 | Outline, Specifications, Tips on Disassembly and Reassembly |
| Maintenance Standards | 48-59 | Maintenance Standards Table, Tightening Torque Table, Sealants and Lubricants Table |
| Special Tools | 60-63 | Special Tools List |
| Overhaul Instructions | 64-67 | Determination of Overhaul Timing, Testing Compression Pressure |
| Preparation for Disassembly | 68-69 | Preparation |
| Main Engine Parts | 70-121 | Cylinder Head and Valve Mechanism, Flywheel, Damper, Timing Gears and Camshaft, Pistons, Connecting Rods, Crankshaft and Crankcase |
| Fuel System | 122-143 | Fuel Filter and Fuel Pipes, Fuel Injection Pipes and Nozzles, Fuel Injection Pump |
| Lubrication System | 144-159 | Oil Filter and Relief Valve, Oil Cooler, Oil Pump, Oil Pan and Oil Strainer |
| Cooling System | 160-171 | Cooling Fan, Fan Pulley and V-Belt, Thermostat, Water Pump |
| Inlet and Exhaust Systems | 172-185 | Turbocharger, Inlet Manifold, Exhaust Manifold |
| Electrical System | 186-211 | Starter, Alternator, Glow Plug |
| Inspection, Adjustment, Break-In Operation and Performance Tests | 212-225 | Adjustment of Engine, Break-In Operation, Performance Tests |
| Others | 226-229 | Disassembly and Reassembly of General Parts |
| Supplement | 230-241 | Engine Inspection Record Sheets |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| All Models | ||
| Water pump discharge capacity | 160 [42.3] £ [U.S.gal] / min at 0.75 MPa (7.5 kgf/cm²) [107 psi] discharge pressure | p. 36 |
| Thermostat case tightening torque | 17.0 to 20.0 N·m | p. 56 |
| Valve clearance (Cold) | 0.25 mm [0.009 in.] | p. 49 |
| Compression Pressure (Swirl chamber) | 3.23 MPa (33 kgf/cm²) [469 psi] | p. 49 |
| Compression Pressure (Direct injection) | 2.94 MPa (30 kgf/cm²) [426 psi] | p. 49 |
| V-belt deflection | 10 to 12 mm [0.39 to 0.47 in.] | p. 49 |
| Cylinder head bolt tightening torque | 113 to 123 N·m (11.5 to 12.5 kgf·m) [83.2 to 90.4 lbf·ft] | p. 55 |
| S4S | ||
| Valve clearance (when engine is cold) | 0.25 mm [0.0098 in.] | p. 121 |
| Engine Oil Capacity (S4S) | 10 L [2.64 U.S.gal] | p. 36 |
| Coolant capacity (S4S) | 5.5 L [1.45 U.S.gal] | p. 69 |
| S6S | ||
| Engine Oil Capacity (S6S) | 12.5 L [3.30 U.S.gal] | p. 39 |
| Coolant capacity (S6S) | 9 L [2.4 U.S.gal] | p. 39 |
Mitsubishi S4S, S6S Common Problems This Manual Covers
Mitsubishi S4S S6S low compression pressure with increased oil consumption, blow-by gas, and hard starting
Move the control lever to STOP, pull the glow plugs, and fit the gage adapter and compression gage as shown on page 66. Crank at 300 min⁻¹ and read every cylinder, never just one. Swirl chamber limit is 2.84 MPa (standard 3.23 MPa); direct injection limit is 2.64 MPa (standard 2.94 MPa). At or below limit, overhaul. Crank no more than 10 seconds, then wait 30 seconds (page 13).
Manual Section: Testing Compression Pressure p. 66Fuel injection nozzle dribbling, diffused, or feathering spray pattern with wrong valve opening pressure
Mount the nozzle on a nozzle tester, bleed air, and pump about one cycle per second following page 135. Opening pressure should be 11.77 to 12.75 MPa (swirl chamber) or 18.14 to 19.12 MPa (direct injection). A 0.1 mm washer change shifts it 1.0 MPa. Clean the needle valve and tip body in wash oil; if spray stays bad, replace the nozzle tip assembly. Never touch the fuel spray (page 135).
Manual Section: Inspection of Fuel Injection Nozzles p. 135Oil pump rotor clearance and end play worn past limit on an engine showing low oil pressure
Measure outer to inner rotor clearance against the 0.20 mm limit on page 150; over limit, replace the outer rotor with the shaft assembly. Check rotor to case end play (0.15 mm limit) and outer rotor to case clearance (0.50 mm limit), and replace the pump if either is exceeded. Then check main shaft to case clearance against the 0.150 mm limit on page 151.
Manual Section: Inspection of Oil Pump p. 150Thermostat valve not starting to open at standard temperature or lift under 9 mm at 90 °C
Test the thermostat in a container of water, stirring with a bar while heating, as page 165 describes. The valve should start opening at 76.5 ± 2 °C and reach 9 mm lift at 90 °C; outside that range, replace it. Check the opening temperature stamped on the flange and torque the thermostat case to 17.0 to 20.0 N·m. This is a hot operation, so guard against burns and fire.
Manual Section: Inspection of Thermostat p. 165Water pump impeller and shaft noisy or binding when rotated by hand, with coolant leaks
Let coolant temperature drop before opening the radiator filler cap or draining, since steam and hot coolant can blow out (page 9). Remove the water pump cover and gasket, then rotate the impeller and shaft by hand following page 166. Any noise or binding means replacing the entire water pump assembly. Inspect for cracks, coolant leaks and deformation, and keep drained LLC out of conventional sewage (page 10).
Manual Section: Inspection of Water Pump p. 166Starter brushes worn short or overrunning clutch slipping on an engine with hard starting
Disconnect the cable from the negative battery terminal before servicing the starter (page 11). Measure brush length and spring load against the limit for your starter part number on page 195; replace brush and holder assemblies at or below limit. Turn the pinion shaft by hand per page 198: smooth clockwise, locked counterclockwise, or replace the overrunning clutch. Test the armature for shorts and grounding on page 196.
Manual Section: Inspection and Repair of Starter p. 195Frequently Asked Questions
What are the torque specifications for the cylinder head, injectors, and connecting rods for the Mitsubishi S4S and S6S engines?
For the S4S and S6S engines, the cylinder head bolts must be tightened to 113 to 123 N-m (11.5 to 12.5 kgf-m). The connecting rod nut cap torque is 49.0 to 59.0 N-m (5.0 to 6.0 kgf-m). For the fuel injection nozzle (swirl chamber specification), the nozzle torque is 53.0 to 64.7 N-m (5.4 to 6.6 kgf-m). p. 55
How do you adjust the valve clearance on a Mitsubishi S4S or S6S engine?
To adjust the valve clearance, ensure the engine is cold. Loosen the lock nut and turn the adjusting screw while measuring with a feeler gage until the gage moves slightly stiff. The standard valve clearance for both inlet and exhaust is 0.25 mm (0.0098 in.). After adjustment, tighten the lock nut firmly and re-check the clearance. p. 213
What are the fuel filter replacement specifications for Mitsubishi S4S, S6S diesel engines?
Fuel filters should be checked for clogging and cracks and replaced every 500 service hours. When installing a new cartridge, clean the mounting surface, coat the gasket with clean fuel oil, and tighten it by hand; do not use a filter wrench for installation. p. 129
What are the oil filter replacement specifications for the Mitsubishi S4S, S6S diesel engine?
Oil filters should be checked for clogging and cracks and replaced every 250 service hours. Before installing the new oil filter, apply engine oil to the gasket. p. 154
What is the specified V-belt tension for the Mitsubishi S4S and S6S engines?
The V-belt tension should be adjusted so that the deflection is 10 to 12 mm (0.394 to 0.472 in.) when pressed with a force of 98 N (10 kgf) at the center of its span. p. 49
Is this Mitsubishi S4S Service Manual a digital download?
This is a 241-page searchable PDF ready for immediate download. Works on any device, so pull it up on your phone while you're under the hood. No shipping, no waiting.
Can I print pages of this Mitsubishi S4S manual for my own shop?
Yes. It prints from any PDF reader, so run off the pages you need for your own repair work.
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