Service parts for the S12A2
Grouped by system, with how many of each the parts manual calls for.
Oil system
1 requiredPrices captured from merchant listings; some links are affiliate links. Confirm against your serial number before ordering.
Specifications
| Fuel | diesel |
|---|---|
| Frequency | 60.0 Hz |
| Standby power | 800 kW |
| Emissions | EPA Tier 2 |
Filters & service parts
model family| Item | Spec | Capacity | Part # | Interval | |
|---|---|---|---|---|---|
| Air filter | — | 1000 hr | |||
| Fuel filter | — | 1000 hr | |||
| Oil filter | 36291-00900 | 100 hr | Amazon eBay | ||
| Battery | — | ||||
| Belt | — | 1000 hr | |||
| Coolant | 86.0 | — | 2500 hr | ||
| Coolant filter | — | 43 hr | |||
| Oil | 120.0 | — | 100 hr | ||
| Spark plug | — | 1000 hr |
Compiled from this model's family documentation — may include parts for closely-related variants. Confirm the exact part for your serial number.
Service intervals
40| Item | Action | Hours | Months | Notes |
|---|---|---|---|---|
| Fuel filter handle | Other | 10 hr | Rotate by 1 or 2 turns every day or every 10 service hours | |
| Air filter | Drain | 50 hr | Drain water from the air filter | |
| Air tank | Drain | 50 hr | Drain water from the air tank | |
| Fuel filter water | Drain | 50 hr | Water drain every 50 service hours | |
| Fuel tank | Drain | 50 hr | 2 mo | Drain water and sediment; every 50 service hours or every day |
| Oil filters | Change | 250 hr | 12 mo | First service — First 50 service hours of new or reconditioned engine |
| bolts and nuts | Check | 50 hr | First service — First 50 service hours of new or reconditioned engine | |
| engine oil | Change | 250 hr | 12 mo | First service — First 50 service hours of new or reconditioned engine |
| oil filter | Change | 250 hr | First service — First 50 service hours of new or reconditioned engine | |
| Air-tank safety valve | Check | 250 hr | 12 mo | Check proper operation |
| Bypass oil filter element | Replace | 250 hr | Replace every 250 service hours | |
| Exhaust muffler | Drain | 250 hr | 12 mo | Drain water from the exhaust muffler |
| Oil filter (cartridge type) | Replace | 250 hr | Replace every 250 service hours | |
| Radiator fins | Clean | 250 hr | 12 mo | |
| V-belt tension | Adjust | 250 hr | 12 mo | Check and adjust V-belt tension |
| bypass oil filter | Change | 250 hr | 12 mo | Every 250 service hours or yearly |
| hydraulic governor oil filter | Change | 250 hr | 12 mo | Every 250 service hours or yearly |
| valve clearance | Adjust | 2000 hr | 36 mo | First service — First 250 service hours of new or reconditioned engine |
| Fuel filter (paper element type) | Replace | 1000 hr | Replace every 1000 service hours | |
| Fuel filter element (wire element type) | Clean | 1000 hr | Wash element every 1000 service hours | |
| Fuel filters (cartridge type) | Change | 1000 hr | 24 mo | |
| V-belts | Adjust | 1000 hr | Check V-belts - adjust | |
| air filter | Clean | 1000 hr | 24 mo | General duty chart |
| fuel filter (cartridge type) | Change | 1000 hr | Every 1,000 service hours | |
| zinc rod | Change | 1000 hr | 24 mo | General duty chart: Every 1,000 service hours or every 2 years |
| Bolts and nuts | Adjust | 2000 hr | 36 mo | Re-tighten bolts and nuts; for tightening torque see the service manual |
| Fuel injection nozzle tip | Change | 2000 hr | 36 mo | Check spray condition and adjust fuel-injection pressure after replacement |
| Fuel-injection timing | Adjust | 2000 hr | 36 mo | |
| Intercooler | Clean | 2000 hr | Cleaning: every 2000 hours | |
| Protective units | Check | 2000 hr | 36 mo | Increase in coolant temperature, decrease in oil pressure, overspeed, etc. |
| V-belts | Change | 2000 hr | ||
| fuel control link ball joints | Check | 2000 hr | Change parts if necessary | |
| fuel injection pump (governor) rack movement | Check | 2000 hr | During operation | |
| injection nozzle tips | Change | 2000 hr | Adjust injection pressure after replacement | |
| injection timing | Adjust | 2000 hr | Check injection timing - adjust | |
| Air cooler | Clean | 4000 hr | 60 mo | |
| Fuel-control-linkage ball joint | Change | 4000 hr | 60 mo | Every 4,000 service hours or every 5 years |
| Heat exchanger | Clean | 4000 hr | 60 mo | |
| Vibration damper | Check | 4000 hr | 60 mo | |
| cylinder heads | Check | 4000 hr | Top overhaul every 4,000 to 6,000 service hours |
Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.
Service specifications
60| Type | Item | Value | Unit | Condition |
|---|---|---|---|---|
| Clearance | Camshaft end play | 0.20 to 0.30 | mm | standard |
| Clearance | Camshaft end play limit | 0.40 | mm | limit |
| Clearance | Clearance between bridge and valve rotator (A) | 1.5 | mm | |
| Clearance | Clearance between bridge and valve rotator (B) | 2.5 | mm | |
| Clearance | Clearance between valve bridge and valve rotator (minimum) | 1.5 | mm | |
| Clearance | Connecting rod end play | 0.60 to 0.90 | mm | standard |
| Clearance | Connecting rod end play limit | 1.00 | mm | limit |
| Clearance | Crankshaft end play | 0.200 to 0.395 | mm | standard |
| Clearance | Crankshaft end play limit | 0.500 | mm | limit |
| Clearance | Cylinder liner inside diameter | 150.000 to 150.040 | mm | standard |
| Clearance | Cylinder liner inside diameter limit | 150.140 | mm | limit |
| Clearance | Fuel control link ball joint play (maximum before replacement) | 0.1 | mm | |
| Clearance | Fuel control link ball joint play (maximum) | 0.1 | mm | |
| Clearance | Piston outside diameter | 149.78 to 149.82 | mm | at piston skirt |
| Clearance | Piston outside diameter limit | 149.68 | mm | limit |
| Clearance | Timing gear backlash | 0.12 to 0.18 | mm | standard |
| Clearance | Timing gear backlash limit | 0.50 | mm | limit |
| Gap | Piston ring end gap No.1 compression | 0.6 to 0.8 | mm | |
| Gap | Piston ring end gap No.2 compression | 0.5 to 0.7 | mm | |
| Gap | Piston ring end gap Oil | 0.5 to 0.7 | mm | |
| Other | Air-cleaner element cleaning air pressure (maximum) | 0.69 | MPa | |
| Other | Fuel filter cartridge tightening after gasket contact | 3/4 to one | turn | tighten by hand |
| Other | Oil filter cartridge tightening after packing contact | 3/4 to 1 | turn | tighten by hand |
| Other | Priming pump cap additional tightening angle | 120 to 150 | degrees | after tightening by hand until force increases |
| Other | Priming pump cap tightening after hand-tight contact | 120 to 150 | degrees | by wrench; damage above 240 degrees |
| Other | V-belt deflection | 10 to 15 | mm | pressed with thumb at approx. 98 to 147 N |
| Pressure | Air cleaner dust indicator set pressure | 6.23 | kPa | |
| Pressure | Air pressure for cleaning air-cleaner element (maximum) | 0.69 | MPa | 7 kgf/cm2 [100 psi] |
| Pressure | Air tank pressure (air-motor type) | 0.97 | MPa | before starting |
| Pressure | Air tank pressure (direct-air type) | 2.94 | MPa | before starting |
| Pressure | Air tank safety valve opening (air-motor type) | 0.97 | MPa | |
| Pressure | Air tank safety valve opening (direct-air type) | 3.14 | MPa | |
| Pressure | Air-cleaner dust indicator differential pressure | 6.23 | kPa | {635 mmH2O} |
| Pressure | Air-tank safety valve opening pressure (air-motor type) | 0.97 | MPa | 9.9 kgf/cm2 [141 psi] |
| Pressure | Air-tank safety valve opening pressure (direct-air type) | 3.14 | MPa | 32 kgf/cm2 [455 psi] |
| Pressure | Compression pressure | 2.35 | MPa | at 120 to 200 min-1, minimum |
| Pressure | Compression pressure limit | 1.86 | MPa | lower limit |
| Pressure | Compression pressure minimum | 24 | kgf/cm2 | 120-200 rpm |
| Pressure | Engine oil pressure after warm-up | 0.39 to 0.59 | MPa | SAE30 oil; 4 to 6 kgf/cm2 [57 to 85 psi] |
| Pressure | Engine oil pressure after warm-up (SAE30) | 0.39 to 0.59 | MPa | rated speed |
| Pressure | Engine oil pressure after warm-up run at low idle | 0.20 to 0.29 | MPa | 2 to 3 kgf/cm2 [28 to 43 psi] |
| Pressure | Engine oil pressure minimum at low idle | 0.10 | MPa | low idle |
| Pressure | Engine oil pressure minimum at rated speed | 0.29 | MPa | rated speed |
| Pressure | Fuel injection start pressure | 21.57 | MPa | standard value |
| Pressure | Fuel injection start pressure (standard value) | 21.57 | MPa | {220 kgf/cm2} [3,130 psi] |
| Pressure | Injection pressure | 220 | kgf/cm2 | |
| Pressure | Injection starting pressure | 29.4 | MPa | |
| Pressure | Low oil pressure alarm setting above 1,500 rpm | 0.29 or 0.39 | MPa | setting varies with specification |
| Pressure | Low oil pressure alarm setting over entire speed range | 0.15±0.02 | MPa | 1.5±0.2 kgf/cm2 [21±2.8 psi] |
| Pressure | Lubricating oil pressure at idling | 0.20 to 0.29 | MPa | |
| Pressure | Lubricating oil pressure at idling limit | 0.10 | MPa | lower limit |
| Pressure | Lubricating oil pressure at rated speed | 0.49 to 0.69 | MPa | |
| Pressure | Lubricating oil pressure at rated speed limit | 0.39 | MPa | lower limit |
| Pressure | Oil cooler bypass valve opening pressure | 0.44 ± 0.05 | MPa | |
| Pressure | Oil filter alarm differential pressure | 0.15 | MPa | 1.5 kgf/cm2 [21 psi] |
| Pressure | Oil filter alarm lamp lighting pressure | 0.15 to 0.18 | MPa | |
| Pressure | Oil filter differential pressure alarm | 0.15 | MPa | replace filter immediately |
| Pressure | Oil pressure alarm setting | 0.29 or 0.39 | MPa | engine speed higher than 1,500 rpm |
| Pressure | Oil pressure alarm setting (entire speed range) | 0.15 plus/minus 0.02 | MPa | |
| Pressure | Relief valve opening pressure | 0.49 to 0.69 | MPa |
Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.
Recommended fluids
| Fluid | Grade | Standard | Ambient | Capacity | Notes |
|---|---|---|---|---|---|
| Coolant | LLC (Long Life Coolant) | 86.0 L | Coolant capacity (engine): Approx. 86 L [23 U.S.gal] | ||
| Coolant | Long Life Coolant (LLC), all-season non-amine type | Recommended brands: Diamond Diesel Coolant (Nippon Mitsubishi Oil); Fuso Diesel Long Life Coolant (Mitsubishi Motors) | 80.0 L | Non-amine type; concentration 30% to 60% year-round (30% at -10°C, 40% at -20°C, 50% at -30°C, 60% at -45°C); change every 2 years | |
| Coolant | Long Life Coolant (LLC), all-season non-amine type, 30% to 60% concentration | Non-amine, silicate- and borate-free, slightly alkaline | above -45°C | 80.0 L | Recommended brands: Diamond Diesel Coolant (Nippon Mitsubishi Oil), Fuso Diesel Long Life Coolant (Mitsubishi Motors). Change every 2 years. |
| Engine oil | Class CD or CF oil (API service classification) | API | 120.0 L | Engine total: 120 L [32 U.S.gal.] approx. | |
| Engine oil | SAE15W-40 (all seasons) | API Service Classification CF | 100.0 L | Do not use Class CE and CF-4 oils. Avoid mixing oils of different brands. | |
| Engine oil | SAE15W-40 (all seasons); chart also lists SAE30, SAE10W-30, SAE5W-20 | API Engine Service Classification CF (do not use Class CE or CF-4 oils) | 120.0 L | Whole engine capacity, standard type (oil pan 100 L); large type: oil pan 170 L, whole engine 190 L | |
| Fuel | Diesel fuel (ASTM, D975 No.1-D, No.2-D) | ASTM D975 | |||
| Fuel | Diesel oil (JIS K2204) or recommended brands of 'A' heavy oils | JIS K2204, 2205; cetane number 45 or more; sulfur content 0.2 weight % or lower (new use limit); pour point 6°C below ambient temperature; cloud point below ambient temperature | Use fuel with pour point suitable for ambient temperature; water and sediment 0.1 volume % or lower | ||
| Fuel | Diesel oil or A heavy oil | JIS K2204 / JIS K2205 | Cetane number 45 or more; pour point 6 deg C below ambient temperature | ||
| Grease | WPH grease; Molykote; Nikko Grease R; SAE 20W grease combined with 5% molybdenum disulfide | ||||
| Other | Rust preservatives: NP-3 (Diamond PA-3), NP-9 (Diamond PA-90), NP-10 (Diamond PA-10), V.C.I. volatile rust preservative (Diana, JIS K2246) | For storage of engine in inoperative condition: NP-10 for lubrication system, 1:1 NP-9/fuel mixture for fuel system, NP-3 for exposed machined surfaces, volatile preservative for intake system | |||
| Other | Turbine oil ISO VG32 | Oil for the oiler of air-motor type starting system; fill to upper line |
Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.
Procedures
12Adjust V-belt tension adjustment
⚠ Never adjust the V-belts while the engine is running.
⚠ Change the belts if cracked, frayed or cut.
⚠ Keep belts clear of oil or grease.
Tools: Special V-belt gauge 32591-09100, Tension gauge
- Measure belt deflection midway between the pulleys.
- Apply approximately 98 to 147 N (10 to 15 kgf) [22 to 33 lbf] force.
- Deflection should be approximately 10 to 15 mm [0.4 to 0.6 in.]; adjust if incorrect.
- For fan belt: remove belt cover, loosen fan-bracket mounting bolts, turn adjusting rod, tighten bolts.
- For water-pump belt: remove belt cover, loosen tension-bracket bolts, turn tension bolt, tighten bolts.
- For alternator: remove belt cover, loosen alternator mounting bolts, turn adjusting rod, tighten bolts.
Adjust fuel injection timing adjustment
- Make sure the timing mark on the caution plate is aligned with the pointer at No. 1 piston TDC on compression stroke.
- Loosen the one bolt for the fuel injection pump coupling.
- Turn the coupling flywheel until the timing mark on the timer lines up with the pointer.
- Tighten the one bolt; turn the engine to tighten the opposite side bolt and nut.
- Turn the engine two turns to recheck injection timing.
Adjusting V-belt tension adjustment
Tools: V-belt gauge P/N 32591-09100
- Inspect V-belt deflection by pressing with thumb at center of pulley-to-pulley span.
- For fan pulley: loosen fan bracket fixing bolts, adjust with adjusting bolt, tighten lock nut, tighten fixing bolts.
- For tension pulleys: loosen fixing bolts, adjust with adjusting bolt, tighten lock nut, tighten fixing bolts.
- For alternator: loosen fixing and adjusting bolts, move alternator, tighten bolts.
Adjusting valve clearance adjustment
⚠ The valve clearance should be inspected and adjusted when the engine is cold.
Tools: Feeler gauge
- Insert the feeler gauge of the specified thickness between rocker arm and bridge cap.
- Adjust the clearance by turning the screw so that the gauge is gripped softly.
- After adjusting, tighten the lock nut firmly.
- Inspect the clearance again.
Check and adjust fuel injection start pressure adjustment
⚠ Do not allow fuel injected from nozzle to contact skin; high pressure can penetrate skin
Tools: Nozzle tester
- Attach the fuel injection nozzle to the nozzle tester.
- Push the tester handle down slowly while watching the pressure gauge.
- Read the pressure when the needle decreases suddenly; this is the injection start pressure.
- Turn the adjusting screw to obtain standard value (tighten to increase, loosen to decrease).
- Secure the cap nut at 44 plus/minus 5 N-m.
- Check spray conditions: fuel from all nozzle holes, conical spray, fine particles, no drip.
Check and adjust valve clearance adjustment
⚠ Interference between bridge and rotator can dislodge valve cotters if clearance is under 1.5 mm
Tools: Feeler gauge
- Adjust height of two valves with the valve-bridge adjusting screw until no height difference.
- Turn engine to align timing mark [1.6], [2.5] or [4.3] on damper with pointer.
- Check valve clearance with a feeler gauge between rocker arm and bridge cap.
- Loosen lock nut of rocker arm adjusting screw and turn screw until feeler gauge is slightly gripped.
- Tighten the lock nut of the adjusting screw.
- Check and adjust in firing order with each piston at TDC on compression stroke, turning engine in 60 degree increments.
Measure and adjust V-belt deflection adjustment
⚠ Never adjust the V-belts while the engine is running
⚠ Change the belts if cracked, frayed or cut; keep belts clear of oil or grease
Tools: Special V-belt gauge 82591-09100
- Measure the deflection of the belts by applying approximately 98 to 147 N midway between pulleys.
- Adjust if deflection is not approximately 10 to 15 mm.
- For fan belt: remove belt cover, loosen fan-bracket mounting bolts, turn adjusting rod, tighten bolts.
- For water-pump belt: remove belt cover, loosen tension-bracket bolts, turn tension bolt, tighten bolts.
- For alternator: remove belt cover, loosen alternator mounting bolts, turn adjusting rod, tighten bolts.
Tightening cylinder head bolts adjustment
⚠ Observe specified tightening sequence.
Tools: Socket wrench P/N 32591-01100
- Method according to tightening torque: tighten cylinder head bolts to specified torque in sequence.
- Loosen all bolts once, and tighten them again in the same manner.
- Method according to tightening angle: tighten to specified snug torque in sequence.
- Tighten by turning 30 ± 1.5°.
- Tighten further by turning 30 ± 1.5° (total 60 ± 3°).
- Loosen all bolts once, and tighten again by repeating the same procedure.
Testing compression pressure diagnostic
⚠ Measure all cylinders.
⚠ Measure engine speed as well.
Tools: Compression gauge P/N 35A91-03100, Gauge adapter P/N 36291-02200
- Disconnect the main harness from the relay connector.
- Disconnect the high pressure pump solenoid connector.
- Select a cylinder and remove the injector.
- Install a gauge adapter and compression gauge.
- Start the engine using starter and read compression gauge.
- If measured value is at limit or below, overhaul the engine.
Installing main bearing caps installation
⚠ Observe specified tightening sequence.
Tools: Soft-head mallet
- Install the main bearing caps in numerical order from the front end of engine toward the rear end.
- Apply engine oil to the threads of bearing cap bolts.
- Fit the caps in the crankcase using the bolts as a guide.
- Tap each bearing cap with a soft-head hammer.
- Make sure the main bearing caps are firmly in position through side bolt holes.
Bleeding air from fuel system maintenance
⚠ Wipe off spilled fuel thoroughly.
⚠ Lock priming pump cap securely.
- Start at the place nearest to the fuel tank: water separator, fuel filter, injection pump.
- Loosen air vent plug of the water separator.
- Turn priming pump cap counterclockwise to loosen, then move up and down.
- When fuel flowing out no longer contains air bubbles, close the air vent plug.
- Lock priming pump cap by turning clockwise while pushing down.
Change engine oil and oil filters / bypass oil filter maintenance
⚠ Hot oil and components can cause personal injury.
⚠ Do not remove the oil by suction whenever possible.
Tools: Filter wrench, Container, Clean cloth
- Stop the engine, remove the oil pan drain plug and drain the oil while warm.
- Place a container under the oil filter and remove the used cartridge with a filter wrench.
- Clean the filter base with a clean cloth.
- Check the new filter packing is seated, coat packing with clean engine oil.
- Install the new filter; when packing contacts the base, tighten 3/4 to 1 turn more.
- Clean and install the drain plug, fill with recommended oil.
- Run the engine at low idle several minutes and check for leaks.
- Stop the engine, wait about 10 minutes and check the oil level with the dipstick.
Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.
Common questions
What size generator is the Mitsubishi S12A2?
The Mitsubishi S12A2 is rated 800 kW standby.
What fuel does the Mitsubishi S12A2 use?
The Mitsubishi S12A2 runs on diesel.
Which oil filter part number does the Mitsubishi S12A2 take?
The Mitsubishi S12A2 uses oil filter part number 36291-00900.
Troubleshooting
5Fault codes
| Code | Meaning |
|---|---|
| d | Excessive blowby through breather due to worn cylinder liners, pistons, etc. |
| A | A |
| GAIN | GAIN |
| D | D |
| I | I |
Fault codes and symptom→remedy steps extracted from this model’s service/owner documentation; verify against the official manual before servicing.
Repair guides
33- Adjust fuel injection timing
- Adjust V-belt tension
- Adjusting V-belt tension
- Adjusting valve clearance
- Bleeding air from fuel system
- Change engine oil and oil filters / bypass oil filter
- Change fuel injection nozzle tip
- Change oil filters and bypass oil filter
- Change the coolant
- Change the fuel filter (cartridge type)
- Check and adjust fuel injection start pressure
- Check and adjust valve clearance
- Clean or change the air-cleaner element
- Drain and flush the cooling system
- Drain water from the air filter and clean the element (air starting system)
- Engine oil change
- Fill the oil pan
- Fill the radiator
- Installing main bearing caps
- Measure and adjust V-belt deflection
Step-by-step procedures compiled from the Mitsubishi service manual for this model.
Parts
14| Part # | Description | Qty | System | |
|---|---|---|---|---|
| F2515-12000 | WASHER,SPRING | 1 | Oil filter | Amazon eBay $3.00 eBay |
| 05633-41000 | /NUT 6 6 02523 7 | 1 | Service part / kit | Amazon |
| 260719-01 | 7A | Service part / kit | Amazon | |
| 32625-05900 | C/} COUPLING 1 1 V | 311 | Service part / kit | Amazon |
| 34A48-02200 | |WASHER 6 6 02523 7- A | 1 | Service part / kit | Amazon |
| 36232-03600 | /RING 6 6 025340 | 1 | Service part / kit | Amazon |
| 37132-01600 | /RING 6 6 025340 | 1 | Service part / kit | Amazon |
| 37525-07901 | |WASHER 23 23 02523 7- A | 1 | Service part / kit | Amazon |
| 42790-03416 | /U-BOLT 2 2 02523 7 | 1 | Service part / kit | Amazon |
| F1035-12050 | /BOLT 6 6 02523 7- A | 1 | Service part / kit | Amazon |
| F1155-12030 | /BOLT 17 17 02523 7- A | 1 | Service part / kit | Amazon |
| F1155-12040 | /BOLT 7 7 02523 7- A | 1 | Service part / kit | Amazon |
| F2500-10000 | /WASHER, PLAIN 6 6 02523 7- A | 1 | Service part / kit | Amazon eBay $34.95 |
| F2515-10000 | /WASHER, SPRING 6 6 02523 7- A | 1 | Service part / kit | Amazon eBay $7.99 |
Service, wear & replacement parts referenced for this model and its engine — confirm the exact part for your serial number. See the full parts catalog to search and cross-reference.
Available documents
Engine spec — Mitsubishi-Diesel-Engine-S12A2-PTA (Mitsubishi)Engine spec — Mitsubishi-Diesel-Engine-S12A2-PTA2 (Mitsubishi)Spec sheet — MitsubishiS12A2Y2Ptaw2UsersManual231440.1912599600 (Mitsubishi)Reference — Tier-2-Diesel-Engines (Mitsubishi)Owner's manual — Mitsubishi S12A Manual (Mitsubishi)Owner's manual — Mitsubishi S12A2 Manual (Mitsubishi)Parts manual — S12A2 Parts Manual (Mitsubishi)Parts manual — S12A2-Y2PTAW-2 (Mitsubishi)Service manual — Mitsubishi s12a2 (Mitsubishi)Service manual — S12A2 Service Manual (Mitsubishi)
This page was generated from the 10 manufacturer documents above by automated extraction; every figure shown is copied from one of them. How the data is compiled.