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Mitsubishi S12A2 Engine

The Mitsubishi S12A2 is a 33.93 L 12-cylinder turbocharged (ta: with aftercooler and turbocharger; tk: with intercooler and turbocharger) engine, producing up to 500 kW. It powers generator sets from Mitsubishi, including the General Duty Engine and SIZA2. It holds 100 L (26.4 gal) of oil and 80 L (21.1 gal) of coolant.

Also known as: Mitsubishi S12A2

Part of the Mitsubishi S12A2 engine family — 12 variants share parts & fitment.

33.93 L

Displacement

Cylinders

500 kW

Gross power

100.0 L

Oil capacity

On this pageSpecs Generator sets Maintenance FAQ Service intervals Torque & specs Fluids Procedures

Engine specifications

Oil capacity	100.0 L
Coolant capacity	80.0 L
Displacement	33.93 L
Cylinders	12
Aspiration	Turbocharged (TA: with aftercooler and turbocharger; TK: with intercooler and turbocharger)
Gross power	500 kW

Generator sets powered by this engine

Mitsubishi General Duty EngineMitsubishi SIZA2

How to read your Mitsubishi engine serial & model number →

Troubleshooting

Fault 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 engine’s service/owner documentation; verify against the official manual before servicing.

Common problems

White or blue exhaust smoke
Cause: Too much oil in crankcase; Oil viscosity too low; Engine overcooled; Thermostat defective (low water temperature); Injection timing incorrect; Compression pressure low
Fix: Fill only to correct level on gauge; Refill with correct viscosity of oil; Use radiator cover, or clean, test and replace thermostat; Replace; Readjust; Disassemble and replace parts
Water pump defective
Fix: Replace.
Too low oil level
Fix: Maintain oil level in operating range on gauge.
Thermostat defective
Fix: Replace.
Starters will not crank engine or crank slowly, resulting in a failure of engine to start
Cause: Electrical system: Battery — starter switch circuit open; Starters, starter relay defective
Fix: Repair or replace; Adjust alternator drive belt
Starter will crank engine, but engine will not start
Cause: Fuel system: Fuel tank filled; Fuel leaks from pipe; Wrong type of fuel; Dirt or water in fuel; Battery specific gravity low; Electrical system: Alternator drive belt adjustment required; Fuel filters clogged; Circuit defective; Injection pumps defective; Air cleaners clogged; Engine proper: Running parts defective, interference between pistons, foreign matter in cylinder
Fix: Refill with correct type of fuel; Clean or repair fuel filters; Replace; Adjust alternator drive belt; Consult Mitsubishi dealer
Radiator or heat exchanger dirty
Fix: Wash.
Lack of coolant
Fix: Refill.
High oil consumption
Cause: Too high oil level in crankcase
Fix: Maintain oil level in operating range on gauge.
High fuel consumption
Cause: Injection pumps defective; Injection nozzles defective; Injection timing incorrect; Wrong type of fuel
Fix: Disassemble and replace parts; Clean or repair injection nozzles; Readjust; Refill with correct type of fuel
Fan belt loose
Fix: Readjust.
Engine lacks power
Cause: Incorrect grade of oil; Wrong type of fuel; Insufficient air (air cleaner clogged); Engine overcooled; Engine overheating; Valve clearance incorrect; Injection pumps defective; Injection nozzles defective; Injection timing incorrect; Compression pressure low (cylinders and pistons worn)
Fix: Use recommended type and SAE number of oil; Change; Clean or change element; Use radiator cover, replace parts; Flush cooling system or replace parts; Readjust; Readjust or replace; Readjust or replace; Disassemble and replace parts
Compression pressure low
Cause: Insufficient air
Fix: Readjust or replace.
Black or gray exhaust smoke
Cause: Wrong type of fuel; Valve clearance incorrect; Injection pumps defective; Compression pressure low; Insufficient air (air cleaners clogged); Turbocharger defective
Fix: Refill with correct type of fuel; Readjust; Disassemble and replace parts; Clean or change elements; Disassemble and replace parts
Starter will crank engine, but engine will not start.
Cause: Fuel system issues
Fix: Refuel, Check connection, Fuel pipe defective (Bad quality fuel) > Change fuel. Air in fuel system > Prime. Consult your Mitsubishi dealer. Fuel filter clogged > Clean or repair. Fuel pipe restricted or leaky > Clean or repair. Fuel feed pump defective > Consult your Mitsubishi dealer. Air & EArAustoy systems Air cleaner clogged > Clean element. Fuel injection pump detective > Consult your Mitsubishi dealer.

Compiled from service & troubleshooting documentation across every generator set that uses the Mitsubishi S12A2.

Maintenance schedule

Item	Spec	Part #	Interval
Air filter		—	1000 hr
Fuel filter		—	1000 hr
Oil filter	Replace oil filter with a new one every 100 hours or as needed.	36291-00900	100 hr	Amazon eBay
Battery		—	3650 hr
Belt	V-belt gauge	32591-09100		Amazon
Coolant	Change coolant every 2,500 hours or as needed. Drain and refill with new coolant.	—	2500 hr
Coolant filter		—	1000 hr
Oil		—	1000 hr
Spark plug	Replace spark plugs every 1,000 hours or as needed. Use correct spark plug type.	—	1000 hr

Pooled from every document that names this exact engine — confirm the interval and part number against your unit's serial number.

Service intervals

Item	Action	Hours	Months	Notes
Air filter	Drain	50 hr		Drain water from the air filter
Air tank	Drain	50 hr		Drain water from the air tank
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
Exhaust muffler	Drain	250 hr	12 mo	Drain water from the exhaust muffler
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 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
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
protective devices	Check	4000 hr		Coolant temperature, oil pressure, overspeed, etc.
starter and alternator	Check	4000 hr
turbocharger shaft	Check	4000 hr
Engine (standby duty)	Test		1 mo	Once a month run with more than 1/2 load for 15 to 30 minutes
LLC concentration in coolant	Check		6 mo	Every 6 months; wash coolant tank inside
battery electrolyte level	Check		1 mo	Standby chart
coolant	Change		24 mo	Every 2 years; LLC retains efficacy for two years

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

Type	Item	Value	Unit	Condition
Clearance	Clearance between valve bridge and valve rotator (minimum)	1.5	mm
Clearance	Fuel control link ball joint play (maximum before replacement)	0.1	mm
Clearance	Fuel control link ball joint play (maximum)	0.1	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	applying 98 to 147 N force midway between pulleys
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 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	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	Oil filter alarm differential pressure	0.15	MPa	1.5 kgf/cm2 [21 psi]
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
Resistance	Battery electrolyte specific gravity for recharge	1.22	-	at 20°C [68°F]; below 1.22 = recharge
Specification	Battery electrolyte level above plates	10 to 15	mm
Specification	Specific gravity of battery electrolyte - fully charged	1.26 to 1.28		at 20 deg C
Speed	Engine speed during storage preservation run	600	rpm	low idle
Speed	Engine speed for cooling system flushing	800 to 900	rpm
Speed	Engine speed for flushing the cooling system	800 to 900	rpm
Speed	Engine speed when checking fuel leakage at joints	600	rpm	rocker cover removed
Temperature	Coolant temperature (normal reading)	70 to 90	°C	ambient temperature 20 to 30°C [68 to 86°F]
Temperature	Coolant temperature normal range	70 to 90	deg C	ambient 20 to 30 deg C
Temperature	High coolant temperature alarm	92 or 98	deg C	radiator inlet side
Temperature	Oil temperature gauge normal range	70 to 110	deg C
Temperature	Viscous damper surface temperature (maximum)	100	°C	standby-duty engine after one hour operation
Temperature	Viscous damper surface temperature (maximum)	90	°C	prime-power engine after one hour operation
Temperature	Viscous damper surface temperature limit	100	deg C	standby-duty engine, after one hour operation
Temperature	Viscous damper surface temperature limit	90	deg C	prime-power engine, after one hour operation
Temperature	Viscous-rubber damper surface temperature (maximum)	80	°C	prime-power engine
Temperature	Viscous-rubber damper surface temperature (maximum)	90	°C	standby-duty engine
Temperature	Viscous-rubber damper surface temperature limit	80	deg C	prime-power engine
Temperature	Viscous-rubber damper surface temperature limit	90	deg C	standby-duty engine
Torque	Cylinder head	40	kgf-m	Wet
Torque	Eyebolt securing fuel leak-off pipe	15 to 20	N-m
Torque	Fuel injection nozzle tip retaining nut	59 to 78	N-m	apply oil to the nut; do not use Moly Disulfide
Torque	Fuel leak-off pipe eyebolt	15 to 20	N-m
Torque	Nozzle adjusting screw cap nut	44±5	N-m
Torque	Nozzle cap nut (after injection pressure adjustment)	44 plus/minus 5	N-m
Torque	Nozzle gland nut	78	N-m
Torque	Nozzle tip retaining nut	59 to 78	N-m	Apply oil to the nut; do not use Moly Disulfide

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	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	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 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
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

Adjust 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.

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.

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.

Change oil filters and bypass oil filter maintenance

⚠ Change the engine oil when replacing the oil filter

Tools: Filter wrench, Container

Clean dirt and dust off the filter surface and place a container under the oil filter.
Using a filter wrench, remove the used oil-filter cartridge.
Check the used element for metal debris; consult your Mitsubishi dealer if found.
Clean the filter base with a clean cloth.
Check the new filter packing is properly seated, then coat packing with clean engine oil.
Install the new filter; when packing contacts the base, tighten 3/4 to 1 turn more by hand.

Change the coolant maintenance

⚠ Check coolant level only after the engine has stopped and the filler cap is cool enough to touch.

⚠ Dispose of drained antifreeze coolant according to local regulations.

Tools: Container

Run the engine until coolant temperature reaches 70 to 80°C [158 to 176°F].
Allow the engine to cool to room temperature, relieve pressure and remove the radiator cap.
Loosen the engine and water pump drain plugs, remove the radiator drain plug and drain coolant.
Remove the drain plugs of the air cooler pipes and drain.
Flush with cleaning solution at 800 to 900 rpm for about 15 minutes, drain.
Fill with clean water, run at 800 to 900 rpm for about 10 minutes, drain; repeat until draining water is clear.
Pour pure undiluted LLC into the radiator, then add soft water slowly to the required concentration.
When full, tighten the radiator cap, crank the engine several times for 10 seconds to bleed air.
Operate until coolant is 70 to 80°C, stop and check the coolant level.

Change the fuel filter (cartridge type) maintenance

⚠ Spilled fuel is a fire hazard; wipe off any spilled fuel

Tools: Filter wrench, Drip pan

Clean dirt and dust off the surface of the fuel filter.
Place a drip pan under the fuel filter.
Using a filter wrench, remove the used filter.
Clean the gasket of the new filter and coat it with clean diesel fuel.
Clean the filter base; install the new filter and tighten 3/4 to one turn more after gasket contact, by hand.
Prime the fuel filter after replacement.
Start engine and run at low idle several minutes; check filter base for leaks.

Clean or change the air-cleaner element maintenance

⚠ Never service the air cleaner when the engine is running.

⚠ Wear a protective face shield, goggles and protective clothing when using pressurized air.

⚠ Do not clean the element by bumping or tapping.

Tools: Pressurized air supply

Direct pressurized air inside the element along the length of pleats, maximum 0.69 MPa (7 kgf/cm2) [100 psi].
Insert a light inside the clean dry element and inspect; discard if rips or tears are found.
To change: remove the cap from the air cleaner body.
Remove the wing nut securing the element and take out the used element.
Install a new element and refit the wing nut and cap.

Drain and flush the cooling system maintenance

⚠ Antifreeze contains alkali; avoid contact with skin and eyes

⚠ Dispose of drained coolant according to local regulations

Start the engine and operate until coolant temperature reaches 70 to 80 deg C.
Allow engine to cool to room temperature, relieve pressure, then remove the radiator cap.
Loosen the engine and water pump drain plugs and remove radiator drain plug; drain coolant.
Remove air cooler pipe drain plugs (one each side) and drain coolant.
Close drain plugs, fill with cleaning solution and operate at 800 to 900 rpm about 15 minutes; drain.
Fill with clean water and operate at 800 to 900 rpm about 10 minutes; repeat until draining water is clear.

Drain water from the air filter and clean the element (air starting system) maintenance

⚠ Slowly open the starting-valve handle of the air tank; otherwise the engine could start suddenly.

Close the starting-valve handle of the air tank.
Remove the drain plug from the bottom of the air tank and allow water to drain from the air filter.
Remove the cover from the air filter and take the element out.
Wash the element in diesel fuel and dry by blowing air.
Install the element, attach the cover.
Slowly open the starting-valve handle of the air tank.

Extracted from the manufacturer documentation linked to this model. Values are copied as printed; confirm against your unit's manual and serial number.

Parts cataloged across the Mitsubishi S12A2 family

115

Part #	Description	Category
300204	adjusting screw (5)	Adjusting screw
3-10	Coolant drain cock - water pump	Air filter
3-21	Air Cleaner Element Replacement	Air filter
300082	Speed control lever	Air filter
300085	Speed control lever	Air filter
300086	Air cleaner (air-motor starting)	Air filter
300089	Air cleaner indicator (paper-element type)	Air filter
300096	Air filter (air-motor starting)	Air filter
300100	Air filter (direct-air starting)	Air filter
300103	Air cleaner (oil-bath type)	Air filter
300104	Air cleaner case	Air filter
300111	Air filter (silencer type)	Air filter
300115	Air cleaner element (paper-element type)	Air filter
300116	Air filter element (direct-air starting)	Air filter
300092	Air tank (air-motor/direct-air starting)	Air tank
300097	Air tank (air-motor/direct-air starting)	Air tank
3-14	Air vent cock - inter cooler cooling system	Air vent cock inter cooler cooling system
3-11	Air vent plug - main cooling system	Air vent plug main cooling system
300030	Battery	Battery
300090	Battery	Battery
300112	Fan/water pump/alternator drive belt	Belt
32591-09100	V-belt gauge	Belt
8-25	Air vent cock - inter cooler cooling system	Belt
8-26	DRIVE BELT	Belt
8-16	Cleaning, inspecting, and replacing the air cleaner element	Changing air cleaner element
8-17	Cleaning, inspecting, and replacing the air cleaner element	Changing air cleaner element
3-24	Checking air Cleaner	Checking air cleaner
3-16	Checking battery electrolyte level	Checking battery electrolyte level
3-23	Checking fuel control tink	Checking fuel control tink
3-17	Checking specific gravity of electrolyte	Checking specific gravity of electrolyte
3-18	Cleaning fuel filter (wire-element type)	Cleaning fuel filter wire element type
8-14	Cleaning, inspecting and replacing pre-cleaner	Cleaning pre cleaner
300101	Anti-freeze solution	Coolant
3-15	OIL PUMP AND SUCTION PIPE	Coolant filter
8-18	Coolant drain cock - water pump	Coolant filter
8-19	Coolant drain cock - air cooler water pump	Coolant filter
8-20	Coolant drain cock - engine body	Coolant filter
8-21	Coolant drain cock - water pump	Coolant filter
8-22	Air vent plug - main cooling system	Coolant filter
8-23	Radiator coolant level	Coolant filter
8-24	Coolant drain cock - inter cooler water pump	Coolant filter
300107	Exhaust muffler	Exhaust muffler
3-12	CAMSHAFT LUBRICATION NOZZLE	Fuel filter
300098	Primary fuel filter (wire-element type)	Fuel filter
300099	Secondary fuel filters (paper-element type)	Fuel filter
300122	new cartridge, old cartridge	Fuel filter
300519	apply oil to gasket of a new cartridge. bring gasket into contact with sealing face of bracket, and tighten remove case, and wash dust particles off element	Fuel filter
300939	primary fuel filter (wire-element type) — wash element	Fuel filter
300087	Fuel tank	Fuel tank
300094	Fuel tank	Fuel tank
GM36275	Gasket, cylinder head	Gasket
GM57300	Gasket, cylinder head	Gasket
300046	API Service Classification CD oil	Grease
36291-00900	Fuel Injection Nozzle Tip	Injector
300110	Check bushings for cracks or other defects.	Maintenance
300113	Change zinc rods of heat exchanger, air coolers, etc.	Maintenance
300109	New oil in clean jug, Old oil out of drain plug	Oil change
3-19	Oil filler and oil level gauge	Oil filler and oil level gauge
3-22	OIL FILTER	Oil filter
300106	Bypass oil filter	Oil filter
300114	Governor oil filter (Woodward type)	Oil filter
36291-00098	Oil sample bottle set	Oil filter
36291-19100	Engine oil sampling pump	Oil filter
8-15	Oil filler and oil level gauge	Oil filter
300084	Check to be sure linkage moves smoothly without any	Oil pan
300108	Oil pan	Oil pan
300088	Oiler (air-motor starting)	Oiler
07-01	CRANKCASE ASS~	Service part / kit
3-13	Coolant drain cock - inter cooler water PUMP	Service part / kit
300004	Daily Operation Record	Service part / kit
300517	Full KVA Adapter Cord	Service part / kit
300910	Safety Information Sheet	Service part / kit
300949	Camshaft Rocker shaft	Service part / kit
300950	Water jacket	Service part / kit
300952	Intercooler (left side)	Service part / kit
32522-04111	Thermo label for temperature management (75 to 95°C)	Service part / kit
32522-04211	Thermo label for temperature management (100 to 120°C)	Service part / kit
32522-04311	Thermo label for temperature management (50 to 70°C)	Service part / kit
45499-51400	Warning label	Service part / kit
45499-60700	Warning label	Service part / kit
45A83-51500	Warning label	Service part / kit
500001	thru QA6901.	Service part / kit
GM14491	Cap, sealing	Service part / kit
GM14569	Guide, valve	Service part / kit
GM15167	Nut	Service part / kit
GM15180	Washer, spring	Service part / kit
GM15518	Cap, sealing	Service part / kit
GM36261	Head assembly, cylinder	Service part / kit
GM36262	Seat, inlet, standard	Service part / kit
GM36263	Seat, inlet, 0.3 oversized	Service part / kit
GM36264	Seat, inlet, 0.6 oversized	Service part / kit
GM36265	Seat, exhaust, standard	Service part / kit
GM36266	Seat, exhaust, 0.3 oversized	Service part / kit
GM36267	Seat, exhaust, 0.6 oversized	Service part / kit
GM36270	Stud	Service part / kit
GM36271	Connector	Service part / kit
GM36272	Bolt, cylinder head	Service part / kit
GM36273	Bolt, cylinder head	Service part / kit
GM36274	Washer	Service part / kit
GM57296	Head assembly, cylinder	Service part / kit
GM57297	Seat, inlet, standard	Service part / kit
GM57298	Seat, inlet, 0.3 oversized	Service part / kit
GM57299	Seat, inlet, 0.6 oversized	Service part / kit
NP-10-2	rust-preventive oil	Service part / kit
SCR25	Mitsubishi SCR system	Service part / kit
3-20	Radiator Cap	Radiator cap
300102	Rust inhibitor	Rust inhibitor
GM14529	Washer, sealing	Seal
300105	Silencer (precleaner)	Silencer
300947	max. speed setting	Speed setting
32522-04100	Thermo Label 75°C to 95°C (167°F to 203°F)	Thermostat
32522-04200	Thermo Label 100°C to 120°C (212°F to 248°F)	Thermostat
300948	Turbocharger	Turbocharger
300091	Valves in pipeline	Valve
41-1	Warning labels	Warning label

Parts cataloged across all variants of this engine family — verify the exact part fits your specific variant and serial number before ordering.

Aftermarket parts that fit this engine

32501-04201 FridayParts $65.00 37734-01700 FridayParts $259.89 3754906600 FridayParts $60.45 30N20-00101 FridayParts $744.78 3436102090 FridayParts $1448.59 ME755056 FridayParts $1448.59 9410610309 FridayParts $1448.59 101605-9511 FridayParts $1448.59 32C65-04040 FridayParts $1838.00 092000-4550 FridayParts $1838.00 32666-10300 FridayParts $649.99 04442-45400 FridayParts $235.56 3436102071 FridayParts $1545.90 3436102070 FridayParts $1545.90 37501-80V50 FridayParts $2346.80 094500-6040 FridayParts $520.89 30L65-00700 FridayParts $520.89 094500-3800 FridayParts $551.87 MM433648 FridayParts $551.87 MM433649 FridayParts $529.79 094500-3820 FridayParts $529.79 MM433647 FridayParts $529.79 094500-3910 FridayParts $529.79 30L65-05101 FridayParts $553.89 094500-8460 FridayParts $553.89 30L65-05500 FridayParts $553.89 094500-8530 FridayParts $553.89 30L65-05701 FridayParts $553.89 094500-8580 FridayParts $553.89 30L65-04300 FridayParts $553.89 094500-8660 FridayParts $553.89 30L65-05900 FridayParts $553.89 094500-8740 FridayParts $553.89 MM437628 FridayParts $363.69 30L65-05300 FridayParts $363.96 094500-8510 FridayParts $363.96 094500-8560 FridayParts $369.96 30L65-05601 FridayParts $369.96 30L65-05600 FridayParts $369.96 30L65-05200 FridayParts $369.96 094500-8500 FridayParts $369.96 ME440071 FridayParts $59.98 41069-04302 FridayParts $79.99 34401-03200 FridayParts $68.98 3774520501 FridayParts $398.57 3-Year FridayParts $11.99 36205-20100 FridayParts $1232.50 ME064526 FridayParts $51.00 3756-707400 FridayParts $113.99 S16R2 FridayParts $42.00 04541-86200 FridayParts $178.66 FP-XP-0040393

Parts listed by aftermarket suppliers as fitting this engine — leads compiled from supplier catalogs; verify the exact part for your serial number.

Also used in

Hitachi EX1900-5 — Excavator Tracked

Other equipment known to use this engine, via filter-application cross-reference — useful for sourcing parts even when your exact machine isn't listed elsewhere on this page.

Common questions

What is the oil capacity of the Mitsubishi S12A2?

The Mitsubishi S12A2 engine has an oil capacity of 100.0 liters.

What is the displacement of the Mitsubishi S12A2?

The Mitsubishi S12A2 has a displacement of 33.93 liters with 12 cylinders.

Which generators use the Mitsubishi S12A2 engine?

The Mitsubishi S12A2 powers 2 generator set(s), including Mitsubishi General Duty Engine, Mitsubishi SIZA2.

How often should you change the oil in the Mitsubishi S12A2?

The Mitsubishi S12A2 oil change interval is every 1000 hours.

What is a common problem with the Mitsubishi S12A2 engine?

A commonly reported issue on generators using the Mitsubishi S12A2 is: White or blue exhaust smoke. Cause: Too much oil in crankcase; Oil viscosity too low; Engine overcooled; Thermostat defective (low water temperature); Injection timing incorrect; Compression pressure low. Fix: Fill only to correct level on gauge; Refill with correct viscosity of oil; Use radiator cover, or clean, test and replace thermostat; Replace; Readjust; Disassemble and replace parts.

Mitsubishi S12A2 Engine

Engine specifications

Generator sets powered by this engine

Troubleshooting

Fault codes

Common problems

Maintenance schedule

Repair guides

Service intervals

Service specifications

Recommended fluids

Procedures

Parts cataloged across the Mitsubishi S12A2 family

Aftermarket parts that fit this engine

Also used in

Common questions