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CAT C7 Engines

CAT C7 Engine

Caterpillar C7 EngineThe CAT C7 is an inline-six diesel engine with a minimum power output of 168 bkW (228 hp), and a maximum power output of 224 bkW (304 hp), along with a rated speed of 1,800-2,200 rpm. The production of the Caterpillar's C7 engine lasted from 2003 to 2009, a period which saw it installed predominantly in medium-duty and Class 8 trucks. Notable trucking companies in the industry all invested in the CAT C7, optimistic that it would live up to what Caterpillar had promised.

Unfortunately, the Caterpillar C7 was hit by the harsher, Tier 4 emissions standards that went into effect in 2004. The C7 had only just been released the previous year. Cat’s C7 engine had a few notable problems, with roughly half of them experiencing engine failures at (or before) 500,000 miles, often requiring an overhaul. However, this failure rate doesn't differ at all much from a lot of competitor engines produces in the Tier 4 era.

Engine Applications and Uses

  • Box Trucks
  • Tow Trucks
  • Day Cabs
  • Straight Trucks


Common CAT C7 Engine Problems & Failures

When engines fail, some are salvageable while others, depending on the extent of the damaged incurred, just aren't worth the time and money to repair. After 40 years of experience, we at Big Bear Engine Company know the pattern of problems and common failure points associated with the C7. Below, we've listed its most frequent problems.
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  • Spun Crankshaft Bearings
  • Scored Pistons
  • Overfueling
  • Lifter/Roller Failure
  • Lack Of Oil or Oil Pressure
  • Crankshaft Failure
  • Cracked Cylinder Head
  • Connecting Rod Failure
  • Extreme Blow By
  • Dropped Valves
  • Camshaft Failure

Caterpillar C7 Engine Replacement Options

Unfortunately, there is an extensive range of issues that can immobilize your C7. In some instances, your only option may be to replace the engine. However, other situations might only require a few new parts to bring the engine back to life. Or, the engine may be in need of a well-deserved refresh. Each instance is unique and differs from the next.  Of course, cost, time, and availability will factor into your decision-making process, so let's take a look at the pros and cons of buying a new engine from the dealer.

Remanufacturing Process

If a customer is unfortunate enough to have their engine suffer a serious internal failure but is lucky enough to be able to re-use some of their external components, a remanufactured C7 long block is a great option. A long block is also an ideal solution for customers on tighter budgets.

As for long block builds at Big Bear Engine Company, our team of experienced machinists and engine builders will perform a full core tear down, cleaning, inspection, and machining of the engine before it leaves our facility. This ensures each engine leaves here in perfect operating condition every single time.

We'll also note that all of our remanufactured CAT C7 long blocks are built with a mixture of both reman and new parts. We do not recondition or refurbish old engine parts. Instead, we completely rebuild your old Caterpillar C7 engine back to its OEM specs.

Thorough Cleaning

Every CAT C7 we rebuild begins with stripping the block, head, rods and camshaft, which are then thoroughly cleaned in a chemical jet wash or hot tank. This ensures a good starting foundation at the outset of our remanufacturing process.


The crankshaft is precision machined to exact tolerances, polished, and then magnafluxed. From there, it is thoroughly inspected by our quality control department.

Cylinder Head

To guarantee a proper sealing surface with the block and to achieve a finish that’s compatible with the latest head gasket materials available, the head is appropriately resurfaced. Valve height is mic’d and the head is also vacuum tested to assure correct valve seating.


We use magnetic particle to vigorously inspect the block for any cracks or damage in the casting. To eliminate cylinder distortion after the head is installed and torqued to the block, the crankcase is bored and honed to precise tolerances. This also rules out a major cause of engine blow-by. All block surfaces are machined and then inspected to ensure proper finish.


Each camshaft is inspected and precisely machined to provide correct lift. Lobes are measured with a micrometer to make sure all OEM tolerances are met.

Connecting Rods

New bushings are fitted and machined in all bushed rods. Each rod is then carefully inspected for bend and twist. Following that, the connecting rods are cleaned, machined to OEM specifications, and then honed to the standard diameter of original equipment for even distribution of stress across the bearings.

New Parts

Brand new parts such as pistons and rings, bearings, gaskets, and seals all come as standard equipment on our CAT C7 long block builds. These new parts ensure dependable performance and reliability throughout the life of your engine. All new parts are a combination of both OEM and aftermarket, when available.

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Remanufactured Engine Standards

Wearable parts are replaced in every long block build, and all CAT C7 engine core materials are inspected and examined against the original specifications to ensure correct dimensional tolerances. After all, the goal of remanufacturing is to make the engine as close to new as possible. Replacement parts are either new or requalified. If new, the parts are made in the exact same production fashion as the original Caterpillar C7 engine components were. Testing is then performed to manufacturer specifications and original production standards to make certain the engine is ready for durable, long-term operation.

CAT C7 Long Block Parts List:


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

*Note: We can provide a new oil pump, oil cooler, water pump, turbo, injectors and fuel pump for additional cost(s) with the long block, but these components will not come assembled to the engine.

**1-Year Warranty: 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 C7 Engine Specs

Engine Data

Emission StandardsChina Stage II, U.S. EPA Tier 3 Equivalent, EU Stage IIIA Equivalent
Engine ConfigurationInline-Six (I-6), 4-Stroke Diesel
Bore4.33 inches (110mm)
Stroke5.00-inches (127mm)
AspirationTurbocharged and Aftercooled
Displacement7.2L (442 ci)
Compression Ratio16.2:1
Combustion SystemDirect Injection
Rotation from Flywheel EndCounter-Clockwise

Call Big Bear Engine Company 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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