Komatsu S6D140 Marine Engine Parts
The Komatsu S6D140 belongs to Komatsu’s heavy-duty 140-series diesel engine family. It is an inline six-cylinder, four-stroke diesel engine designed for demanding applications where durability, mechanical simplicity and long service life are important.
Unlike the turbocharged SA6D140 and turbocharged/aftercooled SAA6D140 configurations, the S6D140 is the naturally aspirated member of the family.
That difference matters when ordering parts.
An intake component, exhaust component or gasket used on an SA6D140 should not automatically be assumed to fit an S6D140 simply because both engines belong to the 140-series family.
For marine and marinized installations, another factor must also be considered: the engine may have been in service for decades.
During that time, components may have been rebuilt, replaced or modified.
Alfa Marine Spare Parts supports Komatsu S6D140 Marine Engine Spare Parts requirements for:
- Routine Maintenance
- Engine Repair
- Cooling-System Repair
- Fuel-System Repair
- Cylinder Head Repair
- Lubrication-System Repair
- Internal Engine Repair
- Major Engine Overhaul
Depending on availability, supply options can include:
- Genuine Komatsu Parts
- OEM-Quality Components
- Selected Aftermarket Parts
- Remanufactured Components
- Maintenance Parts
- Repair Parts
- Overhaul Components
What Is the Komatsu S6D140 Engine?
The Komatsu S6D140 is a six-cylinder, inline, four-stroke diesel engine from Komatsu’s 140-series family.
The engine is naturally aspirated, meaning combustion air enters the engine without the turbocharging arrangement found on the SA6D140 and SAA6D140.
Major engine systems and assemblies include:
- Cylinder Block
- Cylinder Head
- Pistons
- Piston Rings
- Piston Pins
- Connecting Rods
- Crankshaft
- Main Bearings
- Connecting Rod Bearings
- Camshaft
- Timing Components
- Valve Train
- Fuel Injection System
- Air Intake System
- Exhaust System
- Cooling System
- Lubrication System
- Starting System
- Charging System
For older engines, these serviceable mechanical systems are particularly important because major components can often be inspected individually during repair or overhaul.
Komatsu S6D140 Technical Information
Specifications can vary according to engine specification and application. The engine identification plate and serial number should therefore be checked before ordering replacement components.
Technical InformationKomatsu S6D140ManufacturerKomatsuEngine Family140 SeriesEngine ModelS6D140Engine TypeHeavy-Duty DieselCylinder ArrangementInline 6-CylinderOperating CycleFour-StrokeBore140 mmStroke165 mmDisplacementApprox. 15.24 LitresAspirationNaturally AspiratedCoolingLiquid CooledLubricationPressure LubricationFuelDiesel
Exact rated speed, power output and application-specific equipment should be confirmed from the particular S6D140 specification.
What Does S6D140 Mean?
The model designation helps identify the engine within Komatsu’s engine family.
The 6 identifies the six-cylinder configuration, while 140 corresponds to the engine family and bore size.
Related models include:
S6D140
SA6D140
SAA6D140
Although these engines are closely related, the complete designation matters when identifying spare parts.
What Is the Difference Between Komatsu S6D140, SA6D140 and SAA6D140?
The main difference involves how combustion air is supplied to the engine.
In general:
S6D140 → Naturally Aspirated
SA6D140 → Turbocharged
SAA6D140 → Turbocharged with Charge-Air Cooling
The S6D140 does not rely on a turbocharger for its normal intake-air supply.
This difference affects parts associated with:
- Air Intake
- Intake Manifold
- Exhaust Manifold
- Exhaust Connections
- Air Pipework
- Cooling Arrangement
- Gaskets
- Mounting Components
Some internal engine components may be related across the family, but interchangeability should never be assumed solely from the similar model names.
Does the Komatsu S6D140 Have a Turbocharger?
The standard S6D140 is naturally aspirated.
This is an important distinction when identifying the engine.
If the engine in front of you clearly has a turbocharger, verify the complete identification plate rather than assuming it is an S6D140.
It may belong to another 140-series configuration or may have undergone modification.
What Spare Parts Are Available for the Komatsu S6D140?
Parts requirements can range from routine filters and seals to major internal engine components.
Fuel-System Parts
Potential requirements include:
- Fuel Injectors
- Injector Components
- Fuel Injection Components
- Fuel Transfer Components
- Fuel Filters
- Fuel Pipes
- Fuel Return Components
- Injector Seals
- Gaskets
- O-Rings
Air Intake and Exhaust Parts
Potential requirements include:
- Air Filters
- Air Cleaner Components
- Intake Pipes
- Intake Manifold Components
- Exhaust Manifold Components
- Exhaust Connections
- Intake Gaskets
- Exhaust Gaskets
- Clamps
- Seals
- Fasteners
Cooling-System Parts
Potential requirements include:
- Cooling-Water Pump
- Water-Pump Components
- Thermostats
- Thermostat Housing Components
- Cooling Pipes
- Cooling Hoses
- Oil Cooler Components
- Gaskets
- O-Rings
- Seals
Lubrication-System Parts
Potential requirements include:
- Engine Oil Pump
- Oil Pump Components
- Engine Oil Filters
- Oil Cooler
- Oil Pressure Components
- Oil Pipes
- Oil Lines
- Gaskets
- O-Rings
- Crankshaft Seals
Cylinder Head Parts
Potential requirements include:
- Complete Cylinder Head
- Cylinder Head Gasket
- Intake Valves
- Exhaust Valves
- Valve Guides
- Valve Seats
- Valve Springs
- Rocker Components
- Valve-Train Components
- Injector Sealing Components
- Valve Cover Gaskets
Internal Engine Parts
Potential requirements include:
- Pistons
- Piston Rings
- Piston Pins
- Piston Pin Bushings
- Connecting Rods
- Connecting Rod Bearings
- Main Bearings
- Thrust Components
- Crankshaft
- Camshaft
- Timing Components
Komatsu S6D140 Fuel-System Parts
The fuel system has an important job: delivering clean fuel consistently to all six cylinders.
Potential requirements can include:
- Fuel Injectors
- Injector Components
- Fuel Injection Components
- Fuel Transfer Components
- Primary Fuel Filters
- Secondary Fuel Filters
- Fuel-Water Separator Elements
- High-Pressure Fuel Pipes
- Fuel Return Components
- Injector Seals
- Fuel-System Gaskets
- O-Rings
What If the Komatsu S6D140 Becomes Difficult to Start?
Hard starting can have several possible causes.
These can include:
- Restricted Fuel Filters
- Poor Fuel Supply
- Air Entering the Fuel System
- Injector Problems
- Fuel Injection Problems
- Low Cylinder Compression
- Valve Problems
- Low Battery Voltage
- Poor Electrical Connections
- Low Starter Cranking Speed
This is why replacing injectors immediately is not always the correct first response.
Fuel supply, compression and cranking performance should also be considered.
Komatsu S6D140 Fuel Injectors
Potential requirements can include:
- Complete Fuel Injectors
- Injector Components
- Injector Seals
- High-Pressure Fuel Pipes
- Fuel Return Components
- Associated Hardware
What Are Possible Signs of an S6D140 Injector Problem?
Possible symptoms can include:
- Difficult Starting
- Rough Running
- Uneven Cylinder Operation
- Increased Exhaust Smoke
- Abnormal Combustion Noise
- Reduced Engine Power
- Increased Fuel Consumption
However, these symptoms do not automatically confirm injector failure.
Poor compression, valve problems or fuel-delivery problems can sometimes produce similar symptoms.
One S6D140 Cylinder Is Running Differently — What Should Be Checked?
The six-cylinder configuration provides a useful opportunity to compare cylinder behavior.
If five cylinders appear normal and one behaves differently, possible areas to investigate include:
- Injector Performance
- Fuel Delivery
- Cylinder Compression
- Intake Valve Condition
- Exhaust Valve Condition
- Valve Adjustment
- Piston Condition
- Piston Ring Condition
- Cylinder Condition
The injector may be responsible, but it should not automatically be assumed to be the cause.
Komatsu S6D140 Air Intake Parts
Because the S6D140 is naturally aspirated, keeping the intake path clean and unrestricted is particularly important.
Potential requirements include:
- Air Filter Elements
- Air Cleaner Components
- Intake Pipes
- Intake Connections
- Intake Manifold Components
- Clamps
- Intake Gaskets
- Seals
Can a Restricted Air Filter Cause an S6D140 to Lose Power?
Yes.
A diesel engine needs sufficient clean air for efficient combustion.
If airflow becomes restricted, possible symptoms can include:
- Reduced Power
- Increased Black Smoke
- Poor Response Under Load
- Increased Fuel Consumption
- Higher Exhaust Temperature
Checking the air cleaner and intake path is therefore a sensible early step when investigating poor engine performance.
Komatsu S6D140 Exhaust-System Parts
Potential requirements include:
- Exhaust Manifold
- Exhaust Manifold Components
- Exhaust Connections
- Exhaust Gaskets
- Sealing Components
- Fasteners
- Associated Hardware
Exhaust leaks should not simply be ignored because the engine continues to operate.
Signs such as soot around manifold joints can indicate a sealing problem that deserves inspection.
Why Can the Komatsu S6D140 Produce Black Smoke?
Black smoke generally indicates that combustion conditions are producing more soot than expected.
Possible causes can include:
- Restricted Air Filter
- Restricted Intake
- Fuel Injection Problems
- Injector Problems
- Excessive Fuel Delivery
- Poor Cylinder Compression
- Excessive Engine Load
Because the S6D140 is naturally aspirated, a turbocharger fault would not be the normal explanation for black smoke on a standard engine.
The intake, fuel and combustion systems should instead be investigated.
Komatsu S6D140 Cooling-System Parts
Potential requirements include:
- Cooling-Water Pump
- Water-Pump Components
- Thermostats
- Thermostat Housing
- Cooling Pipes
- Cooling Hoses
- Oil Cooler
- Temperature Components
- Gaskets
- O-Rings
- Seals
Why Can a Komatsu S6D140 Overheat?
Possible causes can include:
- Low Coolant Level
- Poor Coolant Condition
- Thermostat Problems
- Reduced Water-Pump Performance
- Restricted Cooling Passages
- Oil Cooler Restriction
- Cooling-System Contamination
- Restricted Coolant Flow
For marine installations, the raw-water side must also be considered.
Why Does the S6D140 Overheat Mainly Under Load?
This can be an important troubleshooting clue.
At low load, the engine produces less heat.
When engine load increases, the cooling system must remove significantly more heat.
A partially restricted cooling system may therefore appear acceptable at idle or low load but struggle when the engine is working harder.
Areas to investigate include:
- Coolant Level
- Thermostat
- Cooling-Water Pump
- Cooling Passages
- Oil Cooler
- Coolant Flow
- Cooling-System Restrictions
For a marinized engine, also inspect the seawater circuit.
Komatsu S6D140 Cooling-Water Pump Parts
Potential requirements include:
- Complete Cooling-Water Pump
- Pump Housing
- Pump Shaft
- Bearings
- Mechanical Seal
- Impeller
- Gaskets
- O-Rings
Does an S6D140 Water Pump Have to Leak Before It Needs Attention?
No.
External leakage is only one possible indication.
A pump can also suffer from:
- Bearing Wear
- Mechanical-Seal Problems
- Impeller Damage
- Internal Corrosion
- Cavitation
- Reduced Circulation
Cooling performance should therefore be considered as part of the complete system.
Komatsu S6D140 Thermostat Parts
Potential requirements include:
- Thermostats
- Thermostat Housing Components
- Thermostat Gaskets
- O-Rings
- Seals
- Associated Hardware
Thermostat condition should be considered when investigating abnormal engine temperature.
Komatsu S6D140 Marine Seawater Pump
A marinized S6D140 may use a separate raw-water pump as part of the vessel's cooling arrangement.
Depending on the installation, requirements can include:
- Complete Seawater Pump
- Pump Housing
- Pump Shaft
- Bearings
- Mechanical Seal
- Flexible Impeller Where Applicable
- Wear Plate
- Cover Plate
- Gaskets
- O-Rings
Are All S6D140 Marine Seawater Pumps the Same?
No assumption should be made that they are.
Marine conversion equipment can vary between installations.
The seawater pump may have been supplied as part of the marinization package rather than as a standard base-engine component.
For accurate identification, provide:
- Pump Manufacturer
- Pump Model
- Existing Part Number
- Engine Serial Number
- Clear Photographs
- Mounting Arrangement
- Hose and Pipe Connections
Komatsu S6D140 Marine Heat Exchanger Parts
Depending on the marine installation, potential requirements can include:
- Complete Heat Exchanger
- Heat Exchanger Core
- Tube Bundle
- Housing
- End Covers
- Cooling Connections
- Gaskets
- O-Rings
- Seals
Why Can a Marine Heat Exchanger Gradually Lose Performance?
Over time, the seawater side can become affected by:
- Salt Deposits
- Scale
- Sediment
- Marine Growth
- Corrosion Products
- Debris
This can gradually reduce heat transfer.
The engine may initially operate normally at light load and then begin running hotter when more power is demanded.
Komatsu S6D140 Lubrication-System Parts
Potential requirements include:
- Engine Oil Pump
- Oil Pump Components
- Engine Oil Filters
- Oil Cooler
- Oil Cooler Components
- Oil Pressure Components
- Oil Pipes
- Oil Lines
- Gaskets
- O-Rings
- Front Crankshaft Seal
- Rear Crankshaft Seal
What Can Cause Low Oil Pressure on an S6D140?
Possible causes include:
- Low Engine Oil Level
- Incorrect Lubricating Oil
- Deteriorated Oil
- Restricted Oil Filter
- Oil Pump Wear
- Pressure-Regulating Problems
- Excessive Main-Bearing Clearance
- Excessive Connecting Rod Bearing Clearance
- Internal Engine Wear
- Oil Pressure Sender Problems
Low pressure should therefore not automatically be diagnosed as an oil-pump failure.
If excessive bearing clearance is responsible, installing a new pump will not remove the underlying wear.
Komatsu S6D140 Cylinder Head Parts
Potential requirements include:
- Complete Cylinder Head
- Cylinder Head Gasket
- Intake Valves
- Exhaust Valves
- Valve Guides
- Valve Seats
- Valve Springs
- Rocker Components
- Valve-Train Components
- Injector Sealing Components
- Valve Cover Gaskets
When Should an S6D140 Cylinder Head Be Inspected?
Cylinder-head inspection may become necessary following:
- Severe Overheating
- Coolant Loss
- Cylinder Head Gasket Failure
- Low Compression
- Valve Problems
- Uneven Cylinder Performance
- Abnormal Combustion
- Major Engine Overhaul
Once removed, the head should be properly inspected before deciding whether to rebuild or replace it.
Rebuild or Replace the Komatsu S6D140 Cylinder Head?
Important inspection areas include:
- Cracking
- Corrosion
- Flatness
- Sealing Surfaces
- Intake Valves
- Exhaust Valves
- Valve Seats
- Valve Guides
- Valve Springs
- Previous Machining
- Heat Damage
A serviceable cylinder head may be suitable for rebuilding.
A severely damaged or dimensionally unsuitable head may require replacement.
Komatsu S6D140 Pistons and Piston Rings
Potential requirements include:
- Pistons
- Piston Ring Sets
- Piston Pins
- Piston Pin Bushings
- Retaining Components
Possible signs of piston, ring or cylinder wear include:
- Excessive Blow-By
- Increased Oil Consumption
- Reduced Compression
- Difficult Starting
- Exhaust Smoke
- Reduced Engine Performance
Does Excessive Blow-By Mean the S6D140 Only Needs New Rings?
Not necessarily.
The problem can involve:
- Piston Ring Wear
- Cylinder Wear
- Piston Wear
- Ring-Groove Wear
- Internal Engine Damage
Installing new piston rings without checking the cylinder and piston condition may not correct the problem.
Komatsu S6D140 Connecting Rod Parts
Potential requirements include:
- Connecting Rods
- Connecting Rod Bearings
- Big-End Bearings
- Small-End Bushings
- Connecting Rod Bolts
- Associated Hardware
Connecting rods should receive careful inspection following bearing failure, lubrication problems or serious piston damage.
Komatsu S6D140 Crankshaft and Bearing Parts
Potential requirements include:
- Complete Crankshaft
- Main Bearing Sets
- Connecting Rod Bearings
- Big-End Bearings
- Thrust Bearings
- Thrust Components
- Front Crankshaft Seal
- Rear Crankshaft Seal
Why Should the S6D140 Crankshaft Be Measured Before Ordering Bearings?
This is particularly important with an older engine.
The crankshaft may previously have been:
- Polished
- Repaired
- Reground
- Replaced
During overhaul, inspection should consider:
- Main Journal Diameter
- Connecting Rod Journal Diameter
- Surface Condition
- Scoring
- Taper
- Out-of-Round Condition
- Heat Damage
- Previous Machining
If journal dimensions have changed, the required bearing specification may also have changed.
Measure first. Select bearings second.
Komatsu S6D140 Camshaft and Timing Parts
Potential requirements include:
- Camshaft
- Camshaft Bearings
- Timing Gears
- Gear-Train Components
- Timing Covers
- Timing Cover Gaskets
- Valve-Train Components
- Related Bushings
During a major overhaul, these components should be inspected rather than automatically assumed to be reusable.
Komatsu S6D140 Gaskets and Seals
Potential requirements include:
- Complete Engine Gasket Set
- Upper Gasket Set
- Lower Gasket Set
- Cylinder Head Gasket
- Valve Cover Gaskets
- Intake Gaskets
- Exhaust Gaskets
- Oil Cooler Gaskets
- Cooling-System Gaskets
- Injector Seals
- O-Rings
- Front Crankshaft Seal
- Rear Crankshaft Seal
A gasket package should be matched to the exact S6D140 engine specification.
Komatsu S6D140 Overhaul Parts
A planned overhaul may require:
- Pistons
- Piston Rings
- Piston Pins
- Main Bearings
- Connecting Rod Bearings
- Thrust Components
- Connecting Rod Bushings
- Cylinder Head Components
- Intake Valves
- Exhaust Valves
- Crankshaft Seals
- Complete Gasket Set
- Engine Seal Kit
- Fuel-System Components
- Cooling-System Components
- Lubrication-System Components
Depending on inspection results, additional requirements may include:
- Complete Cylinder Head
- Crankshaft
- Connecting Rods
- Camshaft
- Fuel Injectors
- Fuel Injection Components
- Cooling-Water Pump
- Oil Pump
- Oil Cooler
- Starter Motor
- Alternator
Should an S6D140 Overhaul Kit Be Ordered Before Opening the Engine?
Some planned maintenance parts can certainly be prepared in advance.
For a major overhaul, however, the final parts list should ideally follow disassembly and measurement.
Once the engine is open, the workshop can determine:
Are the cylinders still serviceable?
Can the pistons be reused?
Has the crankshaft previously been machined?
Which bearing specification is actually required?
Can the cylinder head be rebuilt?
Are the connecting rods serviceable?
A practical overhaul sequence is:
Identify → Disassemble → Clean → Inspect → Measure → Confirm Parts → Rebuild
This reduces the risk of ordering components based on assumptions about an engine's previous service history.
What Information Should You Send for Komatsu S6D140 Parts?
For accurate Komatsu S6D140 Marine Engine Spare Parts identification, provide:
- Engine Model: Komatsu S6D140
- Complete Engine Variant
- Engine Serial Number
- Engine Identification Plate
- Existing Komatsu Part Number
- Component Manufacturer Number
- Part Description
- Quantity Required
- Clear Photographs
- Vessel or Equipment Application
- Delivery Country or Nearest Port
For fuel equipment, cooling pumps, seawater pumps, starter motors, alternators and marine conversion equipment, identification directly from the component currently installed is particularly useful.
Who Do We Supply?
Alfa Marine Spare Parts supports Komatsu S6D140 requirements for:
- Shipyards
- Ship Repairers
- Marine Engineers
- Chief Engineers
- Technical Superintendents
- Fleet Operators
- Marine Service Companies
- Commercial Fishing Companies
- Offshore Operators
- Government Fleets
- Maritime Contractors
- Boat Builders
- Marine Equipment Distributors
- Commercial Vessel Operators
Worldwide Komatsu S6D140 Parts Supply
Alfa Marine Spare Parts supports Komatsu S6D140 Marine Engine Spare Parts requirements across major international marine markets, including Spain, Italy, Monaco, France, the Netherlands, Belgium, Germany, Greece, the United Kingdom, Dubai and the UAE, Nigeria, Miami and Florida, Texas, Toronto and Canada, the Caribbean, South America and other major international seaports.
Whether the requirement involves filters, injectors, cooling components, a water pump, cylinder head, crankshaft, bearings or components for a complete S6D140 overhaul, accurate identification remains the starting point.