Caterpillar 3400 Series Marine Engine Parts & Spare Parts
Alfa Marine Spare Parts supplies Caterpillar 3400 Series marine engine parts and spare parts for commercial vessels, workboats, fishing vessels, tugboats, offshore vessels, marine propulsion systems, auxiliary engines and generator applications.
We source genuine, OEM, replacement and applicable Reman Caterpillar 3400 components, subject to availability, for routine maintenance, corrective repairs, top-end overhaul and complete engine rebuild requirements.
Our sourcing capabilities cover fuel injectors, fuel injection pumps, cylinder heads, pistons, cylinder liners, piston rings, connecting rods, bearings, crankshaft components, camshaft components, turbochargers, seawater pumps, jacket-water pumps, oil pumps, oil coolers, aftercooler components, filters, gaskets, seals and overhaul parts.
The Caterpillar 3400 family includes several well-known heavy-duty diesel engines, particularly:
- Caterpillar 3406
- Caterpillar 3406B
- Caterpillar 3406C
- Caterpillar 3408
- Caterpillar 3408B
- Caterpillar 3408C
- Caterpillar 3412
- Caterpillar 3412C
- Caterpillar 3412E
For the twelve-cylinder engine, visit our Caterpillar 3412 Marine Engine Parts page.
You can also browse our Caterpillar Marine Engine Parts & Rebuild Kits, Caterpillar Engine Parts Catalogue or Marine Spare Parts Catalogue.
For correct parts identification, provide the complete engine model, engine serial number, serial-number prefix, arrangement number and existing part number whenever available.
Need a specific Caterpillar 3400 Series component? Request a Quote or email request@alfamarinespareparts.com.
What Is the Caterpillar 3400 Series?
The Caterpillar 3400 Series is a family of heavy-duty four-stroke diesel engines produced in several cylinder configurations and generations.
The family became widely established in demanding applications where durability, serviceability and dependable mechanical operation were important.
Important marine members include:
Caterpillar 3406
The 3406 is the inline six-cylinder member of the family.
Different generations include the 3406, 3406B and 3406C.
Caterpillar 3408
The 3408 uses a V8 configuration and has been used in marine propulsion, auxiliary and other heavy-duty applications.
Versions include the 3408, 3408B and 3408C.
Caterpillar 3412
The 3412 is the V12 member of the 3400 family and became particularly well known in commercial marine propulsion and auxiliary applications.
For detailed information, visit our Caterpillar 3412 Marine Engine Parts page.
Caterpillar 3400 Series Engine ModelsEngineConfigurationFamilyCaterpillar 3406Inline 63400 SeriesCaterpillar 3406BInline 63400 SeriesCaterpillar 3406CInline 63400 SeriesCaterpillar 3408V83400 SeriesCaterpillar 3408BV83400 SeriesCaterpillar 3408CV83400 SeriesCaterpillar 3412V123400 SeriesCaterpillar 3412CV123400 SeriesCaterpillar 3412EV123400 Series
The suffix matters when identifying parts.
A 3406, 3406B and 3406C, for example, should not automatically be treated as identical engines.
The same applies to different 3408 and 3412 generations.
Fuel equipment, turbochargers, cooling components, electrical equipment and other components can differ according to generation and engine arrangement.
Caterpillar 3406 Marine Engine
The Caterpillar 3406 is the inline-six member of the 3400 family.
Marine versions have been used for applications including:
- Commercial propulsion
- Fishing vessels
- Workboats
- Auxiliary engines
- Marine generator sets
One later marine version is the Caterpillar 3406C.
Caterpillar documentation identifies the mechanically governed 3406C commercial propulsion engine at applicable ratings of 365–400 bhp (272–298 bkW) at 1,800 rpm.
The engine incorporates marine-specific systems including jacket-water cooling equipment, a water-cooled exhaust manifold and turbocharging.
Individual 3406 configurations can vary substantially, so parts should always be identified against the exact engine.
Caterpillar 3406 Marine Engine Parts
Common 3406 requirements can include:
- Fuel injectors
- Fuel nozzles
- Fuel injection pumps
- Fuel transfer pumps
- Turbochargers
- Cylinder heads
- Intake valves
- Exhaust valves
- Pistons
- Piston rings
- Cylinder liners
- Connecting rods
- Main bearings
- Connecting-rod bearings
- Camshaft components
- Water pumps
- Oil pumps
- Oil coolers
- Filters
- Gaskets
- Seals
- Overhaul components
Always provide the complete designation, such as 3406B or 3406C, rather than simply “3406 Series.”
Caterpillar 3408 Marine Engine
The Caterpillar 3408 is the V8 configuration within the 3400 engine family.
Versions include:
- Caterpillar 3408
- Caterpillar 3408B
- Caterpillar 3408C
The 3408 has been used in demanding marine and other heavy-duty applications.
Typical parts requirements can include fuel-system components, cylinder components, turbocharger parts, cooling-system components, lubrication parts and complete overhaul components.
As with other engines in the family, the suffix and serial number are important for accurate identification.
Caterpillar 3408 Marine Engine Parts
Alfa Marine Spare Parts can assist with applicable 3408 requirements including:
- Fuel injectors
- Fuel nozzles
- Injection-system components
- Turbochargers
- Cylinder heads
- Pistons
- Piston rings
- Cylinder liners
- Connecting rods
- Main bearings
- Connecting-rod bearings
- Crankshaft components
- Camshaft components
- Seawater pumps
- Jacket-water pumps
- Water-pump repair parts
- Oil pumps
- Oil coolers
- Aftercooler components
- Thermostats
- Filters
- Gaskets
- Seals
Before ordering, identify whether the engine is a 3408, 3408B or 3408C.
Caterpillar 3412 Marine Engine
The Caterpillar 3412 is the V12 member of the 3400 family.
It became one of the better-known Caterpillar heavy-duty engines used in marine propulsion and auxiliary applications.
The engine has been installed in applications such as:
- Commercial vessels
- Tugboats
- Fishing vessels
- Offshore support vessels
- Ferries
- Patrol vessels
- Marine generator installations
- Yachts
The 3412 was produced in multiple configurations and generations, making the complete engine designation important when selecting replacement parts.
For a dedicated technical guide and parts information, visit our Caterpillar 3412 Marine Engine Parts page.
Caterpillar 3412 Marine Engine Parts
Common 3412 requirements can include:
- Fuel injectors
- Fuel injection pumps
- Fuel nozzles
- Turbochargers
- Cylinder heads
- Exhaust valves
- Intake valves
- Pistons
- Piston rings
- Cylinder liners
- Connecting rods
- Bearings
- Crankshaft components
- Camshaft components
- Seawater pumps
- Freshwater pumps
- Oil pumps
- Oil coolers
- Aftercooler components
- Filters
- Gaskets
- Seals
- Overhaul kits
Because multiple 3412 generations exist, do not select components based only on the basic 3412 designation.
Caterpillar 3400 Series Parts We Can Source
Alfa Marine Spare Parts can assist with a broad range of Caterpillar 3400 engine requirements.
SystemTypical ComponentsFuel SystemInjectors, nozzles, injection pumps, transfer pumps and filtersCylinder ComponentsCylinder heads, liners, pistons, rings and valvesCranktrainConnecting rods, bearings and crankshaft componentsTurbochargingTurbochargers, cartridges and associated componentsCooling SystemWater pumps, seawater pumps, thermostats and coolersLubricationOil pumps, oil coolers, filters and sealsAir & ExhaustAftercooler, manifolds, turbo and exhaust componentsElectricalStarters, alternators, sensors and related componentsOverhaulPistons, liners, bearings, gaskets, seals and rebuild components
Browse our Marine Spare Parts Catalogue if you already have the required part number.
Caterpillar 3400 Fuel System Parts
Fuel-system design can vary substantially across the 3400 family and between engine generations.
Requirements can include:
- Fuel injectors
- Fuel nozzles
- Fuel injection pumps
- Fuel transfer pumps
- Fuel filters
- Fuel lines
- Governor components
- Injector seals
- Fuel-system gaskets
- Associated fittings
This is one area where the complete engine designation is particularly important.
A fuel-system component for a 3406C should not automatically be selected for another 3406 generation.
The same principle applies to the 3408 and 3412 families.
Caterpillar 3400 Cylinder Heads
Cylinder-head requirements can include:
- Complete cylinder heads
- Intake valves
- Exhaust valves
- Valve guides
- Valve seats
- Valve springs
- Rocker components
- Cylinder-head gaskets
- Seals
- Associated hardware
Cylinder-head configuration can vary according to engine generation and serial-number range.
Always verify the existing part number whenever possible.
Caterpillar 3400 Pistons & Cylinder Liners
Major internal-engine requirements can include:
- Pistons
- Piston rings
- Piston pins
- Cylinder liners
- Liner seals
- Connecting rods
- Connecting-rod bearings
- Main bearings
- Thrust components
- Gaskets
- O-rings
For major engine-overhaul work, identify components against the complete engine serial number and arrangement.
Caterpillar 3400 Crankshaft & Bearing Parts
Cranktrain requirements can include:
- Crankshafts
- Connecting rods
- Main bearings
- Connecting-rod bearings
- Thrust bearings
- Crankshaft seals
- Crankshaft gears
- Vibration-damper components
- Associated hardware
These are high-value engine components, so accurate identification is essential before ordering.
Caterpillar 3400 Turbocharger Parts
Turbocharger requirements can include:
- Complete turbochargers
- Turbocharger cartridges
- Turbine components
- Compressor components
- Bearings
- Seals
- Oil-feed components
- Oil-return components
- Exhaust connections
- Intake connections
- Gaskets
Turbocharger specifications can differ according to engine model, rating and application.
Whenever possible, send the existing turbocharger identification number together with the engine serial number.
Caterpillar 3400 Cooling System Parts
Marine 3400 engines can use cooling arrangements involving closed engine coolant and raw-seawater circuits.
Cooling-system requirements can include:
- Jacket-water pumps
- Sea water pumps
- Raw-water pumps
- Pump repair components
- Heat exchangers
- Oil coolers
- Aftercoolers
- Thermostats
- Cooling pipes
- Mechanical seals
- Gaskets
- O-rings
Cooling arrangements can differ according to the vessel installation.
Do not order a water pump based only on the 3400 family designation.
Caterpillar 3400 Sea Water Pumps
Sea water and raw-water pumps are important service components on many marine 3400 installations.
Depending on the exact engine, requirements can include:
- Complete seawater pump
- Impeller
- Shaft
- Bearings
- Mechanical seal
- Cover
- Gasket
- O-rings
- Pump housing
- Repair components
For example, certain 3408 and 3412 applications use different pump references depending on the exact engine generation and arrangement.
For additional information about Caterpillar marine cooling pumps, read our Caterpillar Auxiliary Sea Water Pumps & Part Numbers guide.
Caterpillar 3400 Lubrication System Parts
Lubrication-system requirements can include:
- Engine oil pumps
- Oil filters
- Oil coolers
- Oil pressure regulators
- Oil lines
- Oil pressure sensors
- Crankshaft seals
- Gaskets
- O-rings
Correct lubrication is essential for protecting bearings, crankshaft surfaces, camshaft components, pistons and turbochargers.
Caterpillar 3400 Electrical Parts
Depending on engine generation and installation, electrical requirements can include:
- Starter motors
- Alternators
- Solenoids
- Temperature sensors
- Pressure sensors
- Wiring
- Switches
- Gauges
- Monitoring components
- Control components
Later engine generations can differ considerably from earlier mechanically controlled versions.
Always identify the exact engine before ordering electrical or control components.
Caterpillar 3400 Overhaul Parts
A Caterpillar 3400 engine overhaul can require:
- Cylinder liners
- Pistons
- Piston rings
- Piston pins
- Cylinder heads
- Intake valves
- Exhaust valves
- Connecting rods
- Main bearings
- Connecting-rod bearings
- Thrust bearings
- Crankshaft components
- Camshaft components
- Fuel-system components
- Turbocharger components
- Cooling pumps
- Oil pumps
- Gaskets
- O-rings
- Seals
The exact overhaul scope should be prepared against the individual engine.
For a V12-specific overhaul requirement, visit our Caterpillar 3412 Marine Engine Parts page.
Caterpillar 3400 Top-End Overhaul Parts
Top-end requirements can include:
- Cylinder heads
- Intake valves
- Exhaust valves
- Valve guides
- Valve seats
- Valve springs
- Rocker components
- Fuel injectors
- Injector components
- Cylinder-head gaskets
- O-rings
- Seals
The exact parts list depends on the engine model, generation and inspection results.
Caterpillar 3406 vs 3408 vs 3412
The principal difference between the major 3400 family members is their cylinder configuration.
EngineConfigurationCylindersCaterpillar 3406Inline6Caterpillar 3408V8Caterpillar 3412V12
The engines belong to the same wider family but should not be treated as identical engines for parts selection.
For example:
3406 injector ≠ automatically 3408 injector
3408 water pump ≠ automatically 3412 water pump
3408 turbocharger ≠ automatically 3412 turbocharger
Always verify the individual part.
Caterpillar 3400 vs 3500 Series
The Caterpillar 3400 and 3500 families are separate engine platforms.
The 3400 family includes engines such as:
- 3406
- 3408
- 3412
The 3500 family includes engines such as:
- 3508
- 3512
- 3516
Although both families have been used extensively in demanding marine applications, their components should not automatically be considered interchangeable.
For information about the larger engine family, browse our Caterpillar 3512 Marine Engine Parts and Caterpillar 3516 Marine Engine Parts pages.
You can also read our Caterpillar C Series vs 3400 & 3500 Marine Engines guide.
Caterpillar 3400 Marine Applications
Caterpillar 3400-family engines have been used across a broad range of marine applications.
These can include:
Commercial Vessels
3400-family engines have been used for propulsion and auxiliary duties in commercial vessel operations.
Fishing Vessels
The family's heavy-duty construction made various configurations suitable for fishing and working vessels.
Tugboats & Workboats
Applicable 3400 engines have been installed where dependable low- and mid-speed torque is important.
Offshore Vessels
Certain 3400 configurations have been used in offshore and auxiliary applications.
Passenger Vessels
Marine configurations have also been used in passenger and ferry applications.
Marine Generator Sets
3400-family engines have been used for auxiliary and electrical power-generation duties.
Searching for a Caterpillar 3400 Part?
When requesting a Caterpillar 3400 component, send as much identification information as possible.
Engine model: 3406 / 3406B / 3406C / 3408 / 3408B / 3408C / 3412 / etc.
Engine serial number:
Serial-number prefix:
Arrangement number:
Existing part number:
Part description:
Quantity:
Required condition:
Photographs:
This is particularly important for:
- Fuel injectors
- Injection pumps
- Turbochargers
- Cylinder heads
- Pistons
- Cylinder liners
- Bearings
- Water pumps
- Sea water pumps
- Oil pumps
- Electrical components
You can also browse our Caterpillar Engine Parts Catalogue or Marine Spare Parts Catalogue.
Why the Caterpillar 3400 Serial Number Matters
Simply requesting:
“Caterpillar 3400 parts”
is usually not enough for accurate parts identification.
Even saying:
“Caterpillar 3412 parts”
may not provide sufficient information for every component.
The safest identification sequence is:
Engine Model → Serial Number → Arrangement Number → Existing Part Number
Individual engines can differ according to:
- Engine generation
- Serial-number range
- Arrangement
- Power rating
- Propulsion or generator application
- Fuel-system configuration
- Turbocharger arrangement
- Cooling-system arrangement
- Production revision
- Installed auxiliary equipment
Correct identification helps reduce delays and incorrect parts selection.
Why Source Caterpillar 3400 Parts Through Alfa Marine Spare Parts?
Alfa Marine Spare Parts assists shipowners, ship managers, shipyards, marine engineers, repair companies, engine rebuilders and purchasing departments with sourcing Caterpillar 3400 Series parts and overhaul components.
Depending on availability, we can assist with:
- Routine maintenance parts
- Fuel injection components
- Cylinder components
- Internal-engine parts
- Turbocharger components
- Cooling-system parts
- Sea water pumps
- Lubrication-system components
- Electrical parts
- Top-end overhaul requirements
- Major overhaul components
- Genuine components
- OEM components
- Replacement components
- Applicable Reman options
For the complete Caterpillar range, browse our Caterpillar Marine Engine Parts & Rebuild Kits.
Alfa Marine Spare Parts is an independent marine spare-parts supplier and is not an official Caterpillar dealer.
Frequently Asked Questions About Caterpillar 3400 EnginesWhich Engines Belong to the Caterpillar 3400 Series?
Important members include the 3406, 3408 and 3412, with multiple generations and suffixes available.
Is the Caterpillar 3406 a Six-Cylinder Engine?
Yes. The 3406 uses an inline six-cylinder configuration.
Is the Caterpillar 3408 a V8?
Yes. The Caterpillar 3408 is the V8 member of the family.
Is the Caterpillar 3412 a V12?
Yes. The 3412 uses a V12 configuration.
For more information, visit our Caterpillar 3412 Marine Engine Parts page.
Are 3406, 3408 and 3412 Parts Interchangeable?
Not automatically.
Although the engines belong to the same wider family, individual components can differ substantially.
Are 3408 and 3408B Parts the Same?
Do not assume so.
Engine generation, serial number and arrangement should be checked before ordering.
Can You Supply Caterpillar 3400 Overhaul Parts?
Yes. Alfa Marine Spare Parts can assist with applicable pistons, liners, rings, bearings, cylinder components, fuel-system parts, cooling-system components, turbocharger parts, gaskets, seals and other overhaul requirements, subject to availability.
Can You Supply Caterpillar 3400 Sea Water Pumps?
Yes. We can assist with applicable seawater and raw-water pump requirements when the engine and pump references are correctly identified.
Can You Supply Caterpillar 3412 Parts?
Yes. Visit our dedicated Caterpillar 3412 Marine Engine Parts page for additional information.
Related Caterpillar Engine Pages & Guides
Caterpillar 3412 Marine Engine Parts
Caterpillar Marine Engine Parts & Rebuild Kits
Caterpillar Engine Parts Catalogue
Caterpillar 3512 Marine Engine Parts
Caterpillar 3516 Marine Engine Parts
Caterpillar 3600 Marine Engine Parts
Caterpillar C32 Marine Engine Parts
Caterpillar C18 Marine Engine Parts
Caterpillar C Series vs 3400 & 3500 Marine Engines
Caterpillar Auxiliary Sea Water Pumps & Part Numbers
Request Caterpillar 3400 Series Marine Engine Parts
Looking for Caterpillar 3400 Series marine engine parts, maintenance spares, cooling-system components or complete overhaul parts?
Send us:
Engine model: Caterpillar 3406 / 3408 / 3412
Complete engine designation:
Engine serial number:
Serial-number prefix:
Arrangement number:
Existing part number:
Part description:
Quantity:
Required condition: Genuine / OEM / Replacement / Reman where applicable
Vessel name:
Current vessel location:
Delivery destination:
Required date:
If the part number is unknown, include clear photographs of the engine identification plate and existing component.
Email: request@alfamarinespareparts.com
For the V12 model, visit our Caterpillar 3412 Marine Engine Parts page.
You can also browse our Caterpillar Marine Engine Parts & Rebuild Kits, Caterpillar Engine Parts Catalogue and Marine Spare Parts Catalogue.
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