Caterpillar 3116 Engine for Sale | OEM Used 6.6L Inline-6 Medium-Duty Diesel | Predecessor to CAT 3126
$12,000.00
At a Glance
- Condition: OEM used, all 6 cylinders compression tested
- Availability: In stock, CAT 3116 engines available
- Shipping: Free shipping to all 48 contiguous US States via crated freight, 7 to 14 business days
- Donor application confirmed (truck, bus, marine, construction)
- All 6 cylinders compression tested
- Unit injector condition documented
- Turbocharger and aftercooler condition assessed
- Oil pressure verified at idle and operating temperature
- Fuel pump function confirmed
- Block visual inspection
- 100% inspection before every order ships
- No core charge required
- Backed by a 15 day replacement warranty against internal defects
Description
About the Caterpillar 3116 Engine
The 3116 Cat engine is a reliable, turbocharged diesel engine renowned for its robust performance in medium-duty applications. This engine is used in medium-duty trucks, buses, construction machinery, marine propulsion, and heavy industrial applications. If you are searching for a used 3116 Cat engine for sale, you have come to the right place. We offer a wide selection of competitively priced engines to meet your needs, with full donor application identification and inspection documentation.
The CAT 3116 Heritage
The Caterpillar 3116 was produced from 1987 through 1997 as Caterpillar medium-duty Inline-6 diesel engine. The 3116 brought the proven Caterpillar engineering quality and dealer service network to the medium-duty market that had been dominated by Cummins B-series engines. The 3116 uses mechanical unit injection combined with turbocharging and aftercooling, delivering power output from 205 HP through 350 HP across the various configurations for trucks, buses, marine, and industrial applications.
In 1997, Caterpillar replaced the 3116 with the CAT 3126, which added HEUI (Hydraulic Electronic Unit Injection) fuel injection and a slightly larger 1mm bore for improved performance and emissions compliance. The 3126 was succeeded by the CAT C7 engine in 2003 (still in current production for marine and industrial applications), continuing the engineering lineage that began with the 3116.
The Cat Mid-Range Family Context
The 3116 sits at the beginning of the modern Cat mid-range diesel lineage. For buyers researching Cat options across the displacement spectrum, the natural family tree includes our vaz89 listing (CAT C12 12L mid-range Class 8) and vaz85 listing (CAT C15 15L Class 8 line-haul). The 3116 occupies the medium-duty position (6.6L), the C12 the mid-range Class 8 position (12L), and the C15 the heavy-duty Class 8 line-haul position (15L). Cat parts knowledge, ECM diagnostic tools, and service procedures transfer across the family.
Why Buy a CAT 3116 Engine
- Engine Design: 6-cylinder Inline configuration; turbocharged and aftercooled design; displacement of 6.6 liters (403 cubic inches), bore 4.13 inches, stroke 5.00 inches
- Power and Torque: Horsepower output ranging from approximately 205 to 350 HP; strong torque delivery (520-860 lb-ft) especially at lower RPMs, ideal for vocational and commercial applications
- Reliability and Durability: Robust Caterpillar engineering with rugged design; long expected service life under medium-duty conditions
- Fuel Efficiency: Optimized fuel consumption for medium-duty applications; balanced power-to-fuel efficiency ratio
- Emissions Control: Compliance with the EPA emissions regulations in effect during 1987-1997 production
- Serviceability: Caterpillar dealer network support remains strong; easy maintenance and service access
- Adaptability: Suitable for medium-duty trucks, buses, construction equipment, and marine applications; configurable to meet specific application requirements
- Cooling System: Efficient cooling system with belt-driven centrifugal water pump; maintains optimal operating temperatures even under sustained load
The 3116 Cat Engine Fits
The CAT 3116 powered a wide range of medium-duty equipment during its 1987-1997 production:
- Medium-Duty Trucks: International 4700 series, Ford LN series, Freightliner FL series
- Buses: Blue Bird TC2000, Thomas Built Saf-T-Liner MVP ER
- Construction Equipment: Caterpillar 416B Backhoe Loader, Caterpillar 926E Wheel Loader, Caterpillar D30D Articulated Dump Truck, Caterpillar 518 Skidder
- Marine Vessels: Bayliner 3488 Motor Yacht, Hatteras 38 Convertible Sportfish
- Specialty Vehicles: Pierce Arrow XT Fire Truck, Road Rescue Ambulance, various rescue and emergency response vehicles
- Industrial Applications: Stationary generators, irrigation pumps, air compressors
Performance and Efficiency
The CAT 3116 excels in medium-duty performance, offering superior torque and fuel efficiency for its displacement class. Designed to endure the rigors of intensive truck and bus duty cycles while maintaining optimal performance, the 3116 has earned its reputation in the medium-duty diesel market.
Life Expectancy and Maintenance
Maintaining a used 3116 Cat engine is straightforward thanks to its robust mechanical fuel injection design. With proper upkeep, these engines can last between 5,000 to 10,000 hours of service. Regular maintenance includes oil and filter changes, fuel filter replacement, periodic system checks, and proper cooling system service.
Comparisons: 3116 vs 3126 Cat Engines
Understanding the differences between the 3116 and 3126 Cat engines is important for buyers:
- 3116 (1987-1997): Mechanical unit injection, 4.13 inch bore, the original Cat medium-duty 6.6L
- 3126 (1997-2003): HEUI electronic fuel injection, 1mm larger bore (4.17 inch), slightly different ECU calibration, emissions-compliant successor
- C7 (2003-present): Modern successor of the 3126, currently produced for marine and industrial applications
Both 3116 and 3126 share the renowned Caterpillar durability and efficiency. The choice between them often comes down to ECU and fuel system compatibility with the donor equipment.
Customer Reviews and Testimonials
Many satisfied customers have shared their success stories using our used 3116 Cat engines. The consistent feedback points to high satisfaction rates regarding reliability and value compared to dealer reman pricing.
Vehicle Compatibility
| Vehicle | Compatibility |
|---|---|
| International 4700 Series | Medium-duty truck dominant application |
| Ford LN Series | Ford medium-duty truck |
| Freightliner FL Series | Freightliner medium-duty |
| Blue Bird TC2000 | School bus application |
| Thomas Built Saf-T-Liner MVP ER | School bus |
| Pierce Arrow XT | Fire truck chassis |
| CAT 416B Backhoe | Construction equipment |
| CAT 926E Wheel Loader | Construction equipment |
| Bayliner 3488 / Hatteras 38 | Marine applications |
| Industrial/Stationary | Generators, pumps, compressors |
Inspection Workflow
- Donor application confirmed (truck, bus, construction, marine)
- All 6 cylinders compression tested
- Unit injector condition documented
- Turbocharger condition assessed
- Aftercooler condition documented
- Oil pressure verified at idle and operating temperature
- Cooling system inspected
- Block visual inspection
Why Buy From Part Nests
- Donor application confirmed (truck, bus, construction, marine)
- All 6 cylinders compression tested
- Unit injector condition documented
- Turbocharger and aftercooler condition assessed
- Oil pressure verified
- Free crated freight to all 48 contiguous states
- 15 day replacement warranty on internal defects
- Caterpillar-experienced support team on the phone
- Call (855) 634-4447 to confirm 3116 generation (NOT the later 3126 with HEUI or the C7 modern successor), donor application (medium-duty truck, school bus, construction, marine, industrial), and Cat family lineage questions (3116 per this listing, 3126, C7, or C12 per vaz89 mid-range) before ordering
15 Day Replacement Warranty
Every used Caterpillar 3116 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 heads were documented as crack-free at shipping)
- Mechanical unit injector failures within 15 days from installation (where injectors were documented as functional at shipping)
- Turbocharger failures within 15 days from installation (where turbo was documented as functional at shipping)
- Oil pressure failures within 15 days from installation
- Connecting rod, lifter, or bearing failures within 15 days from installation
- Incorrect generation shipped (3116 vs 3126 vs C7) due to an error on our end
What Is Not Covered
- Damage caused during installation
- Damage from running with contaminated fuel (water, dirt, particulates; the mechanical unit injection system is durable but contaminated fuel still causes premature wear)
- Damage from extended oil change intervals or incorrect oil viscosity (Cat-approved ECF-3 or higher 15W-40 required)
- Damage from operating with neglected cooling system
- Damage from over-fueling tune beyond Cat-approved fuel maps
- External components (turbocharger if separately documented, aftercooler if separately documented, harness, intake manifold, exhaust manifold, starter, alternator, A/C, water pump, transmission) 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
- 3116 Generation Confirmed: Mechanical unit injection (NOT the HEUI 3126 or C7 successor)
- Unit Injector Condition Documented: Mechanical fuel system inspection
- Turbocharger and Aftercooler Inspected: Turbo shaft play and bearing wear evaluated
- Oil Pressure Verified: Idle and operating temperature pressure confirmed
- 15 Day Replacement Cover: Internal defects protected from delivery onward
Additional information
| aspiration | Turbocharged and aftercooled |
|---|---|
| bore-x-stroke | 4.13 inches x 5.00 inches |
| compression-ratio | 16.5:1 |
| cooling-system | Water-cooled with belt-driven centrifugal water pump |
| fuel-type | Diesel |
| redline | 2, 600 to 2, 800 RPM |
| engine-type | Inline 6 |
Three generations of the Cat medium-duty 6.6L family. The 3116 (1987-1997, this listing) is the original Cat medium-duty Inline-6 with mechanical unit injection, 4.13 inch bore, and 5.00 inch stroke. The 3126 (1997-2003) added HEUI (Hydraulic Electronic Unit Injection) fuel injection and a 1mm larger bore (4.17 inch) for improved performance and emissions compliance. The C7 (2003-present) is the modern successor to the 3126, currently in production for marine and industrial applications. The three generations share fundamental architecture but use different fuel systems and ECU calibrations. ECM and harness compatibility differs between generations. We confirm the 3116 generation specifically before shipping (not the 3126 or C7).
Cat's pre-HEUI fuel injection system. The 3116 uses Mechanical Unit Injection (sometimes called MUI), where each cylinder has its own unit injector mounted in the cylinder head, mechanically actuated by the engine camshaft. Fuel metering is mechanical (typically via a mechanical fuel rack), not electronic. This is the simpler predecessor to the HEUI system used on the later 3126 (and the Ford 7.3 Powerstroke per our vaz118 listing), which adds high-pressure engine oil actuation and electronic injector control. Mechanical unit injection is highly durable, field-repairable without specialized electronics, and well-suited to vintage medium-duty applications. Modern emissions standards favor HEUI and common-rail systems, but mechanical unit injection on the 3116 remains preferable for many vocational, industrial, marine, and vintage truck restoration applications.
Medium-duty trucks, buses, construction equipment, marine, and industrial. Medium-duty trucks: International 4700 series, Ford LN series, Freightliner FL series. School buses: Blue Bird TC2000, Thomas Built Saf-T-Liner MVP ER. Construction equipment: Caterpillar 416B Backhoe Loader, Caterpillar 926E Wheel Loader, Caterpillar D30D Articulated Dump Truck, Caterpillar 518 Skidder. Marine vessels: Bayliner 3488 Motor Yacht, Hatteras 38 Convertible Sportfish. Specialty vehicles: Pierce Arrow XT Fire Truck (early generations), Road Rescue Ambulance and similar emergency response. Industrial applications: stationary generators, irrigation pumps, air compressors. Tell us your specific application and we will match the correct 3116 variant.
Direct competitor with different design philosophy. The Cummins B-series (5.9L and later 6.7L) was the dominant medium-duty diesel during the 3116 production era. The Cat 3116 brought Caterpillar engineering quality and dealer network to the medium-duty market that Cummins had largely dominated. The 3116 displacement (6.6L) is slightly larger than the original Cummins 5.9L B-series, and the 3116 unit injection differs from the Cummins B-series rotary VE pump (early) or P-pump (mid-range). Both are robust medium-duty diesels with excellent service support; the choice often comes down to dealer access, parts availability, and chassis-specific OEM pairing. For Cat-equipped chassis (especially International, Ford LN, Freightliner FL with Cat option), the 3116 is the natural choice.
5,000 to 10,000 hours of medium-duty service. The 3116 is designed for 5,000 to 10,000 hours of medium-duty service before requiring major rebuild. This translates roughly to 250,000-500,000 miles for medium-duty truck applications (depending on duty cycle and average speed). For school bus service (which logs many hours at lower mileage), the 3116 typically logs 8,000-10,000 hours before rebuild. Industrial / marine applications counting only operating hours generally see 8,000-10,000 hour rebuild intervals. Keys to longevity: regular oil and filter changes, clean fuel, proper cooling system maintenance, and avoiding sustained overload.
Yes, the 3116 is highly rebuildable. Cat rebuild kits are widely available with new pistons, rings, liners, rod and main bearings, head gaskets, valves, and mechanical unit injector rebuild components. Cat-certified rebuilders can perform a complete in-frame or out-of-frame 3116 rebuild for substantially less than a new engine or 3126 / C7 replacement. The mechanical unit injection system can be rebuilt indefinitely by Cat-experienced shops. Many 3116 engines have logged 15,000-plus hours across multiple rebuilds in school bus and industrial service.
Yes for grandfather provisions, no for current model year requirements. The 3116 was manufactured from 1987-1997, before modern EPA emissions standards (EGR mandate 2002, DPF mandate 2007, SCR/DEF mandate 2010) took effect. Trucks and equipment equipped with 3116 engines from the 1987-1997 era are operable today under grandfather provisions in most jurisdictions. However, the 3116 cannot be installed as a replacement engine in a new chassis requiring post-2002 emissions compliance. The 3116 is appropriate for: vintage medium-duty truck restoration (original chassis), pre-emission grandfather use, off-road industrial / marine / construction applications, and equipment categories not subject to on-highway emissions standards.
No. There is no core return required.
2 reviews for Caterpillar 3116 Engine for Sale | OEM Used 6.6L Inline-6 Medium-Duty Diesel | Predecessor to CAT 3126
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Geraldine M. –
Got a 3116 for a 1995 International 4700 medium-duty truck replacement. Generation correctly identified as 3116 (NOT the later HEUI 3126 or C7), mechanical unit injection inspection clean, all 6 cylinders compression tested. Donor application from a similar International 4700 chassis. Honest pre-purchase information about the 3116 vs 3126 generation distinction and the mechanical field-repairability advantage.
Marcus B. –
Sourced a 3116 for a 1994 Blue Bird TC2000 school bus repower. Donor application correctly identified as school bus, oil pressure verified at idle and operating temp, turbocharger and aftercooler inspection clean. Honest pre-purchase information about the 5,000-10,000 hour service life and the mechanical unit injection advantage for fleet service in remote areas without specialized electronics access.