Caterpillar Engines

The name Caterpillar (CAT) is synonymous with heavy industrial vehicles, diesel and natural gas engines, industrial turbines, diesel-electric locomotives, and machinery. It is also most easily identified by the bright yellow color of its vehicles and machinery. Caterpillar has set a benchmark in quality for a wide variety of industries. Since 1925, Caterpillar Inc. has been offering superior results from a team dedicated to helping customers all over the world.

CAT diesel engine technology is a result of decades of evolution and experimentation. The engines meet tough emission standards and deliver performance and efficiency as expected from the company.

History of the Caterpillar Inc.

Caterpillar Inc. formerly known as Caterpillar Tractor Company (1925 – 1986) is a major American manufacturer of high-quality earthmoving, construction, diesel engines, natural gas engines, industrial gas turbines, material-handling, mining, and agricultural equipment. It is headquartered in Peoria, Illinois. The Caterpillar Tractor Company had its origin in two California based companies manufacturing agricultural equipment in the late 19th century. These two companies were headed by Charles Holt and Daniel Best. By 1890 both the companies were manufacturing steam-driven wheeled tractors and harvesters to substitute horse-drawn harvesting machines on large farms.

Benjamin Holt, one of the brothers in the Holt Manufacturing Company, invented the caterpillar tractor. This tractor ran on continuous metal-belted tracks rather than wheels, thus keeping the heavy vehicle from sinking in the ground on the farm. This new machine was immensely successful as all-terrain haulers and graders. With this huge success, Holts opened a new manufacturing plant in Peoria, Illinois, the site of the firm’s future headquarters. During World War I British and American army used these tracks on their armored tanks, and the Holt company flourished further by making thousands of gasoline-powered tractors that transported supplies and ammunition for the army.

Later in 1925, the Holt Manufacturing Company merged with C.L. Best Tractor Company which was founded by the son of Daniel Best. This new company was incorporated as the Caterpillar Tractor Company and moved its headquarters to Peoria. During the Great Depression, the company stayed in business by selling tractors and combines to the Soviet Union. In 1931, Caterpillar manufactured a tractor with a diesel engine and it soon became standard for all types of heavy-duty vehicles, including trucks.

At the time of World War II, Caterpillar company made diesel engines that powered the Sherman (M4) tank and after the war, the company’s tractor and truck sales shot up as these machines were required for reconstruction projects, the building of roads, and dams in countries around the globe. At the beginning of 1961, the company experienced a series of labor conflicts due to the unionized American workforce, but the growth continued and adopted its current name Caterpillar Inc. in 1986.

Caterpillar Inc. now manufactures trucks, excavators, tractors, graders, loaders, scrapers, and other heavy machines for use in agriculture, construction, mining, and industrial warehousing. The company also manufactures diesel and gasoline engines for use in trucks, locomotives, ships, boats, and electricity generated systems and we here at Nationwide Truck Parts sell used diesel Caterpillar engines for trucks.

Caterpillar Diesel Engine Technology

Caterpillar has been experimenting with diesel engine technology throughout its lifetime. The hard work and dedication of engineers at the company brought great results and the product met tough modern standards for fuel emission control. Such advancement served to provide premium quality engines that help support industries worldwide. The functionality of this reliable product has delivered proven efficient results and performance and the company continues to engage in developing and refining advanced technologies to make equipment more productive and efficient.

Now let us see how Caterpillar engines work

How Caterpillar Diesel Engines Work

The diesel engine is a type of internal combustion engine in which the air is compressed in the chamber to high enough temperatures to ignite the fuel injected into the cylinder moving the piston. This converts the chemical energy in the fuel into mechanical energy, which is used to power trucks, locomotives, large tractors, and marine vessels.

Here is a step-by-step view of what happens when a diesel-powered vehicle starts.

Turn the key in the ignition

Turning the key begins the process in which the engine builds up enough heat in the cylinders for starting. The fuel is injected into the cylinders at such a high pressure that it heats the air in the cylinder all by itself. The time taken for all this process is just a few seconds.

Diesel fuel is less unstable as compared to gasoline, thus making it easier to start the engine when the combustion chamber is preheated. With this, manufacturers installed glow plugs that worked off the battery to pre-warm the air in the cylinders when the engine is started. However, with the advancement in technology, better management techniques for fuel came into being and higher injection pressure creates sufficient heat to touch off the fuel without glow plugs. But the plugs are still used for emissions control, the extra heat they provide helps burn the fuel more efficiently. Some vehicles still have these chambers, others do not, but the results are still the same.

The start light goes on

When you see the light, you step on the accelerator and turn the ignition key to start. When this is done, the fuel pump delivers the fuel from the fuel tank to the engine. The fuel, before flowing into the fuel injector nozzles, passes through a couple of fuel filters, so it does not clog the nozzle. Proper filter maintenance is particularly important in diesel fuel because fuel contamination can clog up the tiny holes in the injector nozzles.

The fuel injection pump pressurizes fuel into the delivery tube

The delivery tube, also known as rail, keeps the injection pump at a constant high pressure while it delivers the fuel to each cylinder at the proper interval. The fuel injectors supply the fuel in form of a fine spray into the combustion chambers of the cylinders through nozzles controlled by the engine control unit (ECU). This determines the pressure when the fuel spray occurs, how long it lasts and other functions.

Along with this, another process runs simultaneously to get the air where it needs to be for the final power play. The air is heated to a greater temperature than the temperature at which the injected fuel can ignite. Fuel sprayed into the air that has a higher temperature than the auto-ignition temperature of the fuel instinctively reacts with the oxygen in the air and burns. Air temperatures are typically more than 526 °C (979 °F). Diesel engines are sometimes called compression-ignition engines because initiation of combustion relies on air heated by compression rather than on an electric spark.

Diesel engines operate on either two-stroke or four-stroke cycles.

Two-stroke Engines

In a two-stroke diesel engine, the complete cycle takes place as the piston moves up and down just once.

Exhaust and intake – The air is blown into the cylinder that pushes the old exhaust out through the valves. Then the inlet and exhaust valves close. The piston moves up, thus compressing the air and heating it up. When the piston reaches the top of the cylinder, fuel is injected and immediately ignites.

Power – As the air and fuel mixture burns, the piston is pushed down, driving the crankshaft that powers the wheels.

Four-stroke Engines

A four-stroke diesel engine operates by repeating a cycle of four stages or strokes, during which the piston moves up and down twice.

Intake – Air is drawn into the cylinder through the opening in the valve as the piston moves down.

Compression – Now the inlet valve shuts, and the piston moves up. This compresses the air mixture, heating it up. The fuel is injected into the hot gas through the central fuel injection valve and spontaneously ignites it. Unlike with a gas engine, no sparking plug is needed to make this happen.

Power – As the air and fuel mixture ignites and burns, it pushes the piston down, driving the crankshaft that sends power to the wheels.

Exhaust – The outlet valve on the one end opens to let out the exhaust gases, pushed out by the returning piston.

This is how two and four-stroke diesel engines work. Two-stroke engines are smaller and lighter than four-stroke engines and tend to be more efficient since they produce power once during each rotation. However, they need more lubrication and cooling as well as suffer more wear and tear than the four-stroke engines.

What makes the diesel engine more efficient?

Diesel engines are twice as efficient as gasoline engines. Simply put, it means you can go much further on the same amount of fuel or get more miles for your money. There are numerous reasons for this.

Diesel engines compress more and operate at higher temperatures. A theory of how heat engines work, known as Carnot's rule, tells us that the efficiency of an engine depends on the high and low temperatures between which it operates. A Diesel engine that cycles through higher temperature difference is more efficient.

They lack a sparking-plug ignition system which makes for a simpler design that can easily compress more air, making the fuel burn hotter and completely, releasing more energy. There is another efficiency saving too. In a gasoline engine that is not working at full power, you need to supply more fuel to the cylinder to keep it working, while with diesel engines there is no such issue so they need less fuel when working at lesser power.

These are the reasons that make diesel engines more efficient and used in heavy-duty vehicles and even cars.

Caterpillar Diesel Engines

There are numerous models of CAT diesel engines to choose from. CAT diesel engines range from 11 bhp to 1200 bhp. CAT diesel engines are versatile as they are economically sound and also one of the most energy-efficient ways to operate a vehicle. This is due to Caterpillar’s two lines of Advanced Combustion Emissions Reduction Technology (ACERT) engines. If you are looking to buy reliable, dependable, and heavy-duty diesel engines for most demanding applications, then Caterpillar is a trusted brand of industrial equipment and engines.

Used Caterpillar diesel engines are affordable and are usually in good working condition with a standard warranty intact and tested before sale, as long as you get them from the right seller. You should be able to find a good selection of Caterpillar engines for sale online. When buying a used CAT diesel engine, keep the following things in mind before you make the purchase decision.

Reputation of the Caterpillar Engine Dealer

When buying used Caterpillar diesel engines, be sure to check and verify the reputation of the seller and their product line. Due diligence is important here, always make sure the retailer is reputable and established in selling new, used, and refurbished industrial equipment like engines, generators, and air compressors.

Contact the Seller

The best sellers of used CAT diesel engines offer a free consultation to the customers to help them learn more about their products. The seller also provides suggestions and tips to help you pick the right engine for your needs. If you are a first-time buyer, then it is of great help. If you find a seller that does not provide consultation, then look for other sellers.

Proper CAT Engine Documentation

Used CAT diesel engines are usually sold with the model number, year of fabrication, previous application condition, and operating hours. If you find a Caterpillar diesel engine without these specifications, then it could be a fake. These factors are crucial in determining how reliable the engine is for your purpose. With the maintenance records, you can gain information like the average frequency of maintenance problems and the occurrence of severe problems.

Engine Testing

All the used CAT diesel engines must have completed a load bank test and inspection to ensure its reliability and quality. It is the responsibility of the seller to conduct the test and review the specifications. Reputable sellers only sell used diesel engines that have passed a multi-point review, service, inspection, and testing process and the engines come with the certificate.


Used CAT diesel engines come with a standard warranty, however, ensure that a warranty covers all major parts, so you do not have to pay for the repairs if the issue arises in the future. When you have the warranty, you know whom to turn to.

At Nationwide Truck Parts, we sell various models of used CAT diesel engines. Here are some of the models you can find on our website.

Caterpillar C15

Power – 475 – 595 HP
Torque – 1550 – 2050 lb-ft at 1200 rpm

The CAT C15 is a heavy-duty diesel engine intended for use in a range of industrial applications such as agriculture, material handling, construction, mining, fleet, and line haul. It is an in-line, six-cylinder diesel engine. The C15 delivers performance, power, and durability to take on large powerful challenges.


  • Turbocharged Aftercooled (TA) aspiration
  • MEUI injection system with 2 turbochargers
  • U.S. EPA Tier 4 final emissions
  • The direct injection combustion system
  • Advanced Electronics and Effective Aftertreatment (ACERT) technology
  • ADEM A4 electronics system
  • Emissions - China Nonroad III, U.S. EPA Tier 3 Equivalent, EU Stage IIIA Equivalent

Caterpillar C13 ACERT

Power – 380 – 430 HP
Torque – 1634 lb-ft at 1800 – 2100 rpm

The CAT C13 ACERT diesel engine is offered in ratings ranging from 287-388 bkW at 1800 – 2100 rpm. The ACERT Technology Systems Solution in the engine offers building blocks of air management, advanced electronics, precision combustion, and effective after-treatment for reduced emission. Along with this, it offers outstanding fuel economy and powerful performance.


  • In-line 6, 4 stroke cycle diesel
  • Turbocharged aftercooled (TA)
  • The direct injection combustion system
  • U.S. EPA Tier 4 final, EU stage IV emission standards
  • Fuel combustion optimized
  • Class 8 vehicle usage capability

Caterpillar C12

Power – 340 – 490 HP
Torque – 1650 lb-ft at 1200 rpm

The CAT C12 diesel engine meets IMO II and IMO I emission standards and is best used in trucks with a range of uses from on-highway buses and trucks to industrial vehicles. The Cat C12 is an environmentally friendly engine as it takes full advantage of the electronically controlled unit injection fuel system, resulting in an outstanding fuel economy and performance.


  • In-line 6, 4 stroke cycle diesel
  • Fan-drive mounting bracket
  • ront engine supports
  • Lubricating oil filter and a dry charge coolant conditioner
  • Turbocharged engine and counterclockwise flywheel rotation of the gears
  • Electrical backup system for battery and an extensive self-diagnostic system making it easy to maintain

Other used diesel engines we sell are CAT C13, CAT C7, CAT 3126, and more.