Used Caterpillar 3306 Cat Engine for Sale | OEM Used 10.5L Inline-6 Industrial / Marine / Generator / Heavy Truck Diesel
$12,000.00
At a Glance
- Condition: OEM used, all 6 cylinders compression tested
- Availability: In stock, multiple 3306 variants available (NA, T, B, C, PC, DI)
- Shipping: Free shipping to all 50 states via crated freight, 7 to 14 business days
- All 6 cylinders compression tested, results available before you pay
- Variant confirmed (NA vs turbocharged, mechanical vs electronic, direct injection vs pre-combustion)
- Top-end inspection (heads, injectors, rocker arms)
- Mechanical injection pump operation verified where possible
- Turbocharger condition inspected (on turbocharged variants)
- Donor application documented (construction, generator, marine, agricultural, truck)
- 100% inspection before every order ships
- Backed by a 15 day replacement warranty against internal defects
Description
About the Caterpillar 3306 Cat Engine
The used 3306 Cat engine for sale at Part Nests has become a popular choice for many heavy-duty diesel operators thanks to its high performance, legendary durability, and extensive parts availability compared to other engines in its class. Whether you are in construction, mining, marine, agricultural, generator service, or older Class 8 trucking, the Caterpillar 3306 engine is a trusted workhorse that has powered countless industrial and commercial applications for over three decades.
The 3306 Family Position
The Caterpillar 3306 sits in the middle of Caterpillar traditional industrial / marine / on-highway diesel lineup. For buyers researching the full Cat family lineage:
- 3304 (smaller predecessor, 7.0L Inline-6)
- 3306 (THIS LISTING, 10.5L Inline-6), the workhorse mid-range diesel
- 3406A / 3406B (our vaz83 listing) / 3406C, the larger 14.6L Inline-6 mechanical Cat used in Class 8 trucks; the 3406B is the legendary mechanical variant
- 3406E (our vaz61 listing), the electronic version of the 3406, predecessor to the C15
- C12 (our vaz89 listing), the modern Cat industrial / on-highway successor to mid-range Cat engines
- C15 (our vaz85 listing), the modern Cat heavy-duty successor to the 3406E
In the modern Caterpillar lineup, the 3306 was effectively succeeded by the C9 (in industrial / marine markets) and ultimately by the C13 ACERT (in on-highway truck applications, though the C13 is significantly different architecture). For buyers tracing the Cat heavy-duty diesel lineage, the natural family progression is: 3304 (smaller) → 3306 (this) → 3406B (vaz83, larger mechanical) → 3406E (vaz61, electronic transition) → C12 (vaz89, modern industrial / on-highway) → C15 (vaz85, modern heavy-duty).
Why Choose a Used 3306 Cat Engine
- Engine Configuration: Inline-six with 10.5-liter displacement. Direct injection system delivers better fuel economy and reduces cooling system load compared to pre-combustion chamber designs. Pre-combustion (3306PC) variants are also available for applications requiring that specific fuel system architecture.
- Durability: Constructed with a ribbed cast iron block and top-deck cooling shelf design for improved coolant circulation, ensuring stable engine temperatures even under sustained heavy loads. High manufacturing quality includes a boron steel forged crankshaft and cast aluminum pistons for low wear and long service duration.
- Maintenance and Serviceability: Mechanical fuel system with externally accessible injectors that are easily serviced. Many accessories are directly engaged with gears (water pump, oil pump), reducing belt-driven maintenance requirements and improving long-term reliability.
- Performance: Single fixed-geometry turbocharger (on turbocharged variants) provides consistent power delivery. Management electronics (on 3306C and later production variants) optimize efficiency and fuel consumption while providing diagnostic capability.
- Versatile Applications: Widely used across construction, mining, agricultural, marine, generator, and on-highway truck sectors due to its excellent performance and adaptability across duty cycles.
- Longevity: Engineered for sustained service of approximately 1,000,000 miles or 20,000 to 30,000 operating hours before requiring a major inframe rebuild. This longevity is the foundation of the 3306 enduring market reputation.
- Cost-Effective: A used 3306 represents significant savings compared to purchasing a new or remanufactured engine while delivering comparable remaining service life when properly inspected and maintained.
- Reliability: Caterpillar engines are renowned for their robust performance and longevity, and the 3306 is one of the most-respected examples in the Cat lineup.
- Availability: Used 3306 engines and parts are widely available across North America, reducing lead times and parts cost for your project.
3306 Variants Available
We offer several 3306 variants depending on your application requirements:
| Detail | Description |
|---|---|
| 3306 NA (Naturally Aspirated) | The base 3306, approximately 218 hp. Used in lower-load industrial and marine applications. |
| 3306T (Turbocharged) | Turbocharged 3306, approximately 245-270 hp. Used where higher power output is required. |
| 3306B | The most common 3306 variant, generally turbocharged, with proven reliability across construction, marine, and on-highway truck applications. |
| 3306C | Electronic-control variant of the 3306, with Cat ECM for diagnostic and emissions optimization. |
| 3306PC (Pre-Combustion Chamber) | Pre-combustion chamber fuel system, used in some industrial and marine applications. |
| 3306DI (Direct Injection) | Direct injection variant emphasized in many on-highway truck and modern industrial applications for improved fuel efficiency. |
The 3306 Engine Fits
Construction Equipment:
- Caterpillar 235 / 245 hydraulic excavators
- Caterpillar D6 / D7 dozers
- Caterpillar 966 / 980 wheel loaders
- Compactors and scrapers (various Cat models)
Agricultural Machinery:
- Challenger MT800 series tractors
- Claas Lexion harvesters
- Various large agricultural equipment
Mining Equipment:
- Large haul trucks (mid-size mining applications)
- Mining excavators and loaders
Marine Applications:
- Tugboats and workboats
- Commercial fishing vessels
- Mid-sized recreational yachts
- Various marine propulsion installations
Industrial Applications:
- Caterpillar 3306 generator sets (prime and standby power)
- Industrial pumps (well-service, irrigation, dewatering)
- Air compressors (Sullair and similar industrial compressor packages)
Transport Vehicles:
- Older Class 8 trucks (Peterbilt, Kenworth, Mack with Cat 3306 option)
- Dump trucks and specialty trucks
- Vocational truck applications
Condition and Quality Assurance
When you purchase a used 3306 Cat engine for sale from Part Nests, you can rest assured about the quality and condition of the engine. Our used engines undergo rigorous testing and refurbishment to meet industry standards. Quality measures include:
- Thorough Inspection: Every engine is meticulously inspected for defects or wear
- Performance Testing: Engines are bench-tested where possible to verify operational efficiency
- Variant Authentication: Specific 3306 variant (NA / T / B / C / PC / DI) is documented for ECM and application compatibility
- Donor Application Documented: Construction equipment, generator, marine, agricultural, or on-highway truck origin verified
- Hours / Mileage Documented: Where verifiable from donor records
For precise pricing and availability, please contact us directly at (855) 634-4447.
Here at Part Nests, you will find the best quality used 3306 engine for sale at a very reasonable price. Grab onto this absolute power of an engine, the legendary million-mile Caterpillar 3306.
Signs You Need a Replacement 3306
- Loss of compression on one or more cylinders
- Mechanical injection pump or injector failure
- Turbocharger failure (on turbocharged variants)
- Cylinder head crack symptoms (coolant in oil, white smoke, overheating)
- Connecting rod or main bearing knock under load
- Excessive blow-by or oil consumption
- Donor equipment retired and the 3306 is being moved to another chassis or application
- Generator or industrial repower project requiring proven Cat reliability
- Marine repower (commercial fishing, tug, yacht) requiring 3306-specific engine bed dimensions
Common 3306 Maintenance Considerations
- Oil and filter changes: Every 250 to 500 operating hours for industrial / marine / construction applications, or every 25,000 to 50,000 miles for on-highway truck applications
- Fuel filters: Critical for mechanical injection pump longevity, change at every oil interval
- Cooling system: Use Cat-approved coolant or compatible heavy-duty extended life coolant; service every 2-3 years
- Valve adjustment: Periodic valve clearance check per Cat operating manual
- Injector service: Have injectors flow-tested at major service intervals; replace as needed
- Turbocharger inspection: Check shaft play and exhaust housing condition periodically (turbocharged variants)
What Ships and What Does Not
| Item | Details |
|---|---|
| INCLUDED | Long block: ribbed cast iron block, boron steel forged crankshaft, connecting rods, cast aluminum pistons, camshaft, cast iron cylinder head, valve train, oil pan, valve cover. Mechanical injection pump and injectors typically included from donor where applicable. Turbocharger typically included on turbocharged variants. |
| NOT INCLUDED | ECM (sold separately on electronic 3306C variants), wiring harness, intake manifold (typical), exhaust manifold (typical), starter, alternator, A/C compressor, water pump (sometimes), thermostat, oil cooler, transmission, motor mounts. |
| Fluids | Drained before shipping. Refill with Cat-approved 15W-40 diesel-spec engine oil or compatible API CK-4 / older spec per donor application. |
| Provenance Note | Donor application disclosed (construction, generator, marine, agricultural, on-highway truck). Variant authenticated for ECM compatibility where applicable. |
| Core Note | No core charge. You are not required to return your old engine. |
Vehicle Compatibility
The Caterpillar 3306 was used across an extraordinarily diverse range of platforms:
| Vehicle | Compatibility |
|---|---|
| Caterpillar Construction Equipment | CAT 235 and 245 excavators, D6 and D7 dozers, 966 and 980 wheel loaders, compactors, scrapers |
| Caterpillar Generator Sets | 3306 GenSet (prime and standby power), various industrial power packages |
| Marine Propulsion | Tugboats, fishing boats, mid-size yachts, commercial workboats |
| Agricultural Equipment | Challenger MT800 series tractors, Claas Lexion harvesters |
| Mining Equipment | Mid-size haul trucks, mining excavators and loaders |
| Industrial Equipment | Gardner Denver and Sullair pumps, industrial compressor packages |
| On-Highway Class 8 Trucks | Peterbilt, Kenworth, Mack, Freightliner with Cat 3306 engine option (older production) |
| Specialty Vehicles | Dump trucks, vocational trucks, fire apparatus, military vehicles with Cat 3306 option |
Variants exist with different ECM calibrations for industrial, marine, agricultural, and on-highway truck service. Tell us your application and we will match the appropriate 3306.
Inspection Workflow
Every used Caterpillar 3306 we ship goes through this process:
- All 6 cylinders compression tested, pressure per cylinder recorded
- Variant authenticated (3306 NA / T / B / C / PC / DI)
- Mechanical injection pump operation verified where possible
- Top-end inspection (heads, injectors, rocker arms)
- Turbocharger inspected for shaft play and bearing wear (turbocharged variants)
- Cylinder head visual inspection for cracks
- Donor application photographed and documented
- Approximate hours / mileage documented when verifiable from donor
Why Buy From Part Nests
- All 6 cylinders compression tested, results before you pay
- Variant authenticated (3306 NA, T, B, C, PC, or DI)
- Mechanical injection pump operation verified where possible
- Top-end inspection (heads, injectors, rocker arms)
- Turbocharger and aftercooler inspected (where applicable)
- Donor application traced across the 3306 diverse deployment platforms
- Crated freight delivery to all 50 states for industrial / marine / Class 8 engines
- 15 day replacement warranty on internal defects
- Cat-experienced support team on the phone with knowledge of 3306 variant differences and the engine diverse applications
- Call (855) 634-4447 to confirm 3306 variant (NA, T, B, C, PC, or DI), donor application (construction / mining / generator / marine / agricultural / on-highway truck), Cat family lineage questions (3304 smaller predecessor, 3306 this listing, 3406B per vaz83 mechanical, 3406E per vaz61 electronic, C12 per vaz89 industrial successor, C15 per vaz85 heavy-duty successor), and emissions / electronics architecture before ordering
15 Day Replacement Warranty
Every used Caterpillar 3306 engine purchased through Part Nests carries a 15 day replacement warranty starting on the delivery date.
What Is Covered
- Internal defects already present when the engine arrives
- Compression failures on any of the 6 cylinders beyond what was disclosed
- Cylinder head crack failures within 15 days from installation (where head was documented as crack-free at shipping)
- Mechanical injection pump failures within 15 days from installation (where pump was documented as functional at shipping)
- Turbocharger failures within 15 days from installation on turbocharged variants (where turbo was documented as functional at shipping)
- Connecting rod, lifter, or bearing failures within 15 days from installation
- Incorrect 3306 variant shipped (NA vs T vs B vs C vs PC vs DI) due to an error on our end
What Is Not Covered
- Damage caused during installation
- Damage from running with contaminated diesel fuel (water, dirt, particulates)
- Damage from extended oil change intervals or incorrect oil viscosity (Cat-approved 15W-40 or compatible API CK-4 / older spec per donor application required)
- Damage from operating with neglected cooling system or restricted aftercooler airflow
- Damage from turbocharger over-speed events caused by aftermarket fueling modifications
- Damage from sudden shutdown after sustained high-load operation (turbocharger cool-down period recommended for turbo longevity)
- Damage from aggressive aftermarket tuning beyond Cat-approved fuel maps
- External components (ECM if separately documented on 3306C variants, harness, intake manifold, exhaust manifold, starter, alternator, A/C, water pump, oil cooler, transmission, motor mounts) unless itemized
- Labor expenses of any kind
To start a warranty claim, reach us within 15 days of delivery at (855) 634-4447.
- All 6 Cylinders Tested: Compression results documented before payment
- Variant Authenticated: 3306 NA, T, B, C, PC, or DI documented before shipping
- Top-End Inspection: Heads, injectors, rocker arms condition evaluated
- Mechanical Injection Pump Verified: Operation confirmed where possible
- Turbocharger Inspected: Shaft play and bearing wear assessed (turbocharged variants)
- 15 Day Replacement Cover: Internal defects protected from delivery onward
Additional information
| aspiration | Naturally aspirated or turbocharged, depending on the model |
|---|---|
| bore-x-stroke | 120.7 mm x 152.4 mm (4.75 in x 6.0 in) |
| configuration | Inline 6-cylinder, 4-stroke |
| cooling-system | Liquid-cooled with top-deck cooling shelf |
| displacement | 10.5 liters (640 cubic inches) |
| fuel-system | Mechanical direct injection (with pre-combustion chamber on 3306PC variant) |
| valvetrain | OHV (Overhead Valve), 2 valves per cylinder |
Six configuration variants across the 3306 production span. 3306 NA (Naturally Aspirated) is the base 3306, approximately 218 hp, used in lower-load industrial and marine applications. 3306T (Turbocharged) is the turbocharged 3306, approximately 245-270 hp, used where higher power output is required. 3306B is the most common 3306 variant, generally turbocharged, with proven reliability across construction, marine, and on-highway truck applications. 3306C is the electronic-control variant with Cat ECM for diagnostic and emissions optimization. 3306PC (Pre-Combustion Chamber) uses pre-combustion chamber fuel system, used in some industrial and marine applications. 3306DI (Direct Injection) emphasizes direct injection fuel system for improved fuel efficiency, used in many on-highway truck and modern industrial applications.
Caterpillar mid-range to heavy-duty diesel succession. The 3306 sits in the middle of the Caterpillar mechanical and early-electronic diesel lineup. The natural family progression: 3304 (smaller predecessor, 7.0L Inline-6) → 3306 (this listing, 10.5L Inline-6, the workhorse mid-range) → 3406A / 3406B (the legendary mechanical Class 8 Cat, our vaz83 listing for the 3406B) / 3406C → 3406E (electronic transition, our vaz61 listing) → C12 (modern Cat industrial / on-highway successor, our vaz89 listing) → C15 (modern Cat heavy-duty successor to the 3406E, our vaz85 listing). The 3306 was effectively succeeded in the modern Cat lineup by the C9 (industrial / marine markets) and the C13 ACERT (on-highway, though architecturally different). Each generation has progressive emissions hardware and electronic controls.
1,000,000 miles or 20,000-30,000 hours before major inframe rebuild. The Caterpillar 3306 is engineered for sustained service life of approximately 1,000,000 miles for on-highway Class 8 truck applications, or 20,000 to 30,000 operating hours for industrial, marine, generator, agricultural, and construction equipment applications, before requiring a major inframe rebuild. This longevity is the foundation of the 3306 enduring market reputation. The keys to achieving this service life: regular oil and filter changes (every 250-500 hours or 25,000-50,000 miles), proactive fuel filter changes (mechanical injection pumps are sensitive to fuel contamination), cooling system maintenance (Cat-approved coolant, service every 2-3 years), and periodic valve adjustment per Cat operating manual.
Fuel system architecture and ECU presence. The mechanical 3306 variants (NA, T, B, PC, DI in mechanical configurations) use a mechanical inline injection pump (Robert Bosch, Cat-made, or AmBac depending on production year) with no electronic engine control. This makes the engine extremely field-serviceable in remote markets without specialized electronics. The 3306C variant adds a Cat ECM (Electronic Control Module) for electronic injection timing, diagnostic capability via Cat ET / Caterpillar Electronic Technician software, and emissions optimization. Mechanical 3306s are preferred for repower projects and remote operations where electronics-free service is important; 3306C variants are preferred for applications requiring diagnostic capability and emissions compliance. Variant identification matters for ECU compatibility on cross-chassis swaps.
Extraordinarily diverse, from construction to marine to Class 8 trucks. Construction equipment: CAT 235 / 245 hydraulic excavators, D6 / D7 dozers, 966 / 980 wheel loaders, compactors, scrapers. Generator sets: 3306 GenSet for prime and standby power, various industrial power packages. Marine propulsion: tugboats, workboats, commercial fishing vessels, mid-size recreational yachts. Agricultural equipment: Challenger MT800 series tractors, Claas Lexion harvesters. Mining equipment: mid-size haul trucks, mining excavators and loaders. Industrial equipment: Sullair and similar industrial compressor packages, well-service / irrigation / dewatering pumps. On-highway Class 8 trucks: older Peterbilt, Kenworth, Mack, Freightliner with the Cat 3306 engine option. Variants exist with different ECM calibrations for each duty cycle.
Yes, marine is one of the major 3306 applications. The 3306 is used extensively in commercial marine propulsion: tugboats and workboats (the marine 3306 reputation in tugboat applications is decades-deep), commercial fishing vessels (Pacific Northwest fishing fleets, Gulf of Mexico commercial fishing), mid-size recreational yachts, and various marine workboat applications. Marine 3306 variants have specific marine-grade cooling systems (heat exchanger or keel cooler instead of radiator-cooled), marine-spec accessory drive arrangements (raw water pump, marine alternator), and marine ECU calibration on electronic variants. Confirm marine vs land-based donor when ordering; the cooling system and exhaust differ significantly between the two.
Different displacement classes for different duty cycles. The 3306 (this listing, 10.5L Inline-6) is the mid-range Cat diesel for general industrial, marine, generator, and lighter Class 8 truck applications. The 3406B (our vaz83 listing, 14.6L Inline-6) is the larger heavy-duty Cat diesel for premium Class 8 truck applications and heavy industrial / marine applications. The 3406B produces higher power output (typically 350-475 hp factory production) and higher torque output suitable for heavy line-haul and severe-duty applications. The two are different engines in the same Cat family lineage, with the 3306 serving the mid-range market and the 3406B (later 3406E per vaz61, C15 per vaz85) serving the heavy-duty market. Choose based on chassis size, torque requirement, and donor equipment matching.
No. There is no core return required.
2 reviews for Used Caterpillar 3306 Cat Engine for Sale | OEM Used 10.5L Inline-6 Industrial / Marine / Generator / Heavy Truck Diesel
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Maximilian B. –
Got a 3306B turbocharged for a Caterpillar D6 dozer replacement. Variant correctly identified as 3306B (the most common turbocharged variant), all 6 cylinders compression tested, mechanical injection pump operation verified, turbocharger shaft play assessed clean. Honest pre-purchase information about the Cat family lineage (3304 smaller → 3306 this → 3406B per vaz83 → 3406E per vaz61 → C12 per vaz89 → C15 per vaz85) and the 20,000-30,000 hour industrial service life expectation.
Quintessa A. –
Sourced a 3306C electronic variant for a marine repower project. Variant correctly identified as 3306C (the electronic ECM variant, NOT the mechanical pre-electronic 3306B), all 6 cylinders compression tested, donor marine application documented. Honest pre-purchase information about the marine vs land-based cooling system differences (heat exchanger / keel cooler vs radiator) and the Cat ET diagnostic software requirement for electronic variant service.