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Cat C12 Engine

Cat C12 Engines For Sale

Caterpillar C12 Engine

The C12 Caterpillar is a diesel engine intended for marine propulsion with a range of 345 – 497 mph. The C12 cat engine has a good reputation due to its good performance and even better fuel economy. The fuel economy that makes the C12 the definition of environmentally friendly, is all thanks to the controlled fuel system which enables it to meet EPA Tier 2 commercial, IMO II, and EU IW or RCD emission standards with the exception of the 497 mhp (490 bhp) rating at 2300 rpm which meets IMO I and EU RCD.

The C12 caterpillar is the same size, footprint, and uses the same connection points as the 3196 engine, as well as, the same optional attachments. This makes is an attractive replacement choice.

Engine Applications and Uses

  • Marine

Common CAT C12 Engine Problems & Failures

Cataloged Below are some engine problems and failures commonly reported by people inquiring about replacing their C12 Cat engines. Regrettably, some of the problems include those that could mean the permanent ruin of your engine, but some, if caught early enough, may be saved.

  • AERA Association MemberSpun Crankshaft Bearings
  • Cracked Cylinder Head(s)
  • Dropped Valves
  • Camshaft Failure
  • Crankshaft Failure
  • Lifter/Roller Failure
  • Connecting Rod Failure
  • Scored Pistons and Liners
  • Over Fueling
  • Lack of oil or oil pressure
  • Extreme Blow By

Caterpillar C12 Engine Replacement Options

When it comes to the health of your engine there could be a plethora of problems, worst case scenario, you could be left with a problem where your only route out is complete replacement. However, less tragic situations may just require you to replace some parts or components, or maybe, your engine just needs a new lease of life requiring no more than a refreshment. We are well aware that cost, time, and availability will all affect your decision making - so let us inform you of the pro’s and con’s of a new engine from the dealer.

Remanufacturing Process

A remanufactured C12 Caterpillar long block is a good choice for someone who has experienced an internal engine failure but has been blessed with the gift of re-useable external components that may still be of use from their old motor. Long blocks are also a good option when trying to cut back on costs in the search of a new engine.

Our dedicated team of machinists and engine builders execute a full core tear down, cleaning, inspection, and machining of the engine right before it leaves our facility, ensuring excellence each time.

However, it is important to mention that all our C12 Caterpillar remanufactured long blocks are constructed with a combination of both reman and new parts. We refrain from reconditioning or refurbishing old engine parts, instead we completely rebuild the old C12 motor back to OEM specs.

Thorough Cleaning

Every C12 Cat engine is first entirely stripped. Blocks, heads, rods, crankshafts, and camshafts are carefully cleaned in a chemical jet wash or hot tank to remove stubborn impurities that could eventually facilitate both early component and engine failure.


Crankshafts are precision machined to exact tolerances, polished & magnafluxed, then inspected by our highly attentive quality control department.

Cylinder Heads

Heads are then resurfaced to guarantee a good sealing surface with the block and a finish compatible with today's new gasket materials. Valve height is mic-d and every head is vacuum tested to guarantee correct valve seating.

Cylinder Blocks

Blocks are inspected for both cracks and imperfections with magnetic particle to ensure precise identification. Cylinders are then bored, honed, and inspected to precise tolerances. We then execute a process that aims to eliminate the culprit of engine blow-by. This is achieved by torque plate honing particular engines to eliminate the chances of cylinder head distortion after the head is bolted and torqued to the block.


Camshafts are thoroughly inspected and precisely machined to provide correct lift. Lobs are measured with a micrometer to make sure OEM tolerances are met.

Connecting Rods

Connecting rods are cleansed, then machined to OEM specifications before being honed to the standard diameter of original equipment for even distribution of stress on the bearings. New bushings are also fitted and machined in all bushed rods. Every rod is carefully inspected for bend and twist.

New Parts

Our C12 Caterpillar long block engines receive a standard set of new parts such as pistons and rings, bearings, gaskets and seals, and liners. New parts assure dependable performance and reliability throughout the life of your engine.

Request a Quote

Please fill out the form below with your information and request. A member of our staff will be with you shortly.

Remanufactured Engines Standards

We believe that to remanufacture is to make as close to new as possible. Wearable parts are automatically replaced. All C12 core material is thoroughly inspected and examined against the original equipment specifications for correct dimensional tolerances. Replacement parts are either new or requalified. If new, parts are made in an identical production process as the original equipment. Testing on all of our Cat C12 Engines for sale is also performed to manufacturer specifications and original production standards.

CAT C12 EngineCAT C12 Long Block Parts List:

  • Cylinder Block
  • Complete Loaded Cylinder Head
  • Crankshaft
  • Connecting Rods
  • Timed Front Gear Group
  • Rings
  • Pistons
  • New Upper and Lower Gasket Set
  • Liners
  • Intermediate Cover
  • Followers/Lifters
  • Camshaft
  • **1 Year Warranty

*Note: We can provide new oil pumps, oil coolers, water pumps, turbos, injectors and fuel pumps for additional cost with the long block but will not come assembled to the engine.

**First 6 Months Parts & Labor, Second 6 Months Parts Replacement Only. Ask your sales representative for a full copy of our remanufactured long block warranty

CAT C12 Specs

Engine Data

Configuration In-Line 6, 4-Stroke-Cycle Diesel
Stroke 149mm (5.9 in)
Bore 129 mm (5.1 in)
Aspiration TA
Displacement 732.0 cu in (12 L)
Rotation (from flywheel end) Counter-Clockwise

Give us a call today at 844-340-4114 for immediate sales and support for the Cummins 4BT, Cummins 6BT, 6CT, ISC, 855, QSB 4.5 L or CAT 3306. If you have any questions check out our FAQ Page. We are always ready to help or just listen to your crazy off-roading adventures!

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