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PAI And Their Overhaul Kits Continue To Impress

PAI Diesel Engine Overhaul Kit

PAI Overhaul Kits have become an integral part of our success at Select Reman Exchange and we’d like to share our experience. SRX has been using PAI Overhaul kits exclusively and other products from PAI for several years. 

Before PAI

“In the beginning, we used other manufacturers’ kits that did not seem to be up to our standards and we experienced an uncomfortable rate of failure,” said SRX Production Manager Chuck Pratt.

Production Manager Chuck Pratt observes a technician working on an engine.
PAI Diesel Engine Overhaul Kit
PAI Diesel Engine Overhaul Kit

And when failures occurred getting satisfaction through warranty coverage was not always easy. “When it came time to work with them for warranty purposes, it was very difficult to get any answers and the support we needed for using their products,” added Pratt.

The PAI Difference

We tried several PAI kits and our engine builders were very impressed with the components and packaging quality. 

Since that time we have purchased hundreds of kits and other parts from PAI for our engine builds and we have had tremendous success with their products. With that relatively high number of parts there is bound to be an issue and Pratt underscored how that’s when PAI continued to shine. “We have had only 2 engine failures that were attributed to a product issue, which PAI’s engineering team addressed immediately,” he said.

PAI Diesel Engine Overhaul Kit
PAI Diesel Engine Overhaul Kit

The warranty process is very straightforward and smooth. PAI has surpassed our expectations with their quality of product and their willingness to help when an issue does arise. Pratt added, “their technical support department is better than anyone else’s out there hands down.”

Select Reman Exchange
Select Reman Exchange Team

Thank you to PAI Industries and we look forward to many more years of using your fantastic products keeping our customers’ engines running.

Contact Select Reman Exchange today to learn more about our remanufactured engines and how we can help you get the most out of your diesel engine.

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Is The Caterpillar C15 The Best Heavy-Duty Engine Ever Produced?

Illustrating the block of a Caterpillar C15 diesel engine.

What features and history of the Caterpillar C15 help it compete for the title of best heavy-duty diesel engine? Many people have and continue to argue about it. However, it is not far from the truth. At Select Reman Exchange (SRX) we recognize the Caterpillar C15 as a legendary diesel engine. It’s known for its power, reliability, fuel efficiency, and versatility. Once and still is a very popular choice for many fleets and owner-operators for its performance and reliability.

The Caterpillar C15 diesel is a fantastic on-highway engine. Its ability to handle a wide variety of applications and environments make it a popular choice in other vocations.

The Formidable Caterpillar C15

By Chuck Pratt

Here at SRX, we have been remanufacturing the C15 engine for many years, as well as its predecessor the 3406E. To be transparent, we may be a little biased, because they are our favorite engines to build.

First produced in 1998 by Caterpillar Inc., the C15 “Single Turbo Engine” had numerous applications. C15s are used in construction equipment, agricultural equipment, marine applications, power generation systems and water pumping stations.

The C15 engine is known for its durability and reliability. It is also available in a variety of power ratings. Ranging from 375 horsepower to 625 horsepower from Caterpillar. Many Truck-Rodders push these engines upward of 1000+ horsepower with modifications. One of the key features of the Caterpillar C15 diesel engine is its rock-solid design for durability.

Laboratory tests and engine disassembly analysis, plus years of “actual proof”, have proven the C15 engines typically have a life span of one million miles with Cat’s recommended maintenance schedule. The engine from Caterpillar was built with high-quality materials and components, which helps to ensure long-lasting performance and durability. High-strength connecting rods and a robust crankshaft help to reduce wear and premature bearing failure.

Another key advantage of the Caterpillar C15 is its fuel efficiency. The engine has a number of features that help to reduce fuel consumption, such as an innovative fuel system and a fuel-efficient combustion process. These features help to reduce operating costs for fleets, companies and owner-operators who rely on it.

When Caterpillar designed the C15, it is no secret that it was entirely based on the 3406E.

The 3406E was a solid engine but it needed some improvements for reliability and emissions. One of those key changes that they made was the use of a higher-volume oil pump. With the higher volume oil pump, it obviously would supply better lubrication to the entire engine. But it also helps in reducing the engine operating temperature. In addition to the high-volume oil pump, they upped the volume of the water pump as well for better cooling capabilities. Another benefit Caterpillar added was better gaskets and seals. The “E” Models as they are commonly referred to, had issues with oil leaks and coolant leaks. Some of which were addressed by Cat in the later E-model engines, but not all. Thankfully Caterpillar addressed those issues with the release of the C15.

The first Caterpillar C15

The 6NZ engine serial number prefix was the first Caterpillar C15 diesel to be released. It was first built in July 1998 and enjoyed a lengthy production run until June 2005, with 99,900 engines made. To this day, the 6NZ is a very highly sought-after engine. It is very popular amongst owner-operators who are looking for an engine that will go 1 million miles without all the persnickety little failures that plagued other engine manufacturers from the same time period. The 6NZ C15 was reliable, efficient, and powerful.

In June of 2005, Caterpillar began production of the 9NZ prefix and continued production until February of 2009, with 18,500 engines produced.

Illustrating the block of a Caterpillar C15 diesel engine.

At the end of 2001 Caterpillar began production of the MBN prefix C15. It was produced until February 2003. The MBN is frequently referred to as the “bridge” engine. It was designed to bridge the gap between the pre-emissions 6NZ and the Twin turbo ACERT (Emissions) engines. A choked-out 6NZ was achieved through ECM programming with abysmal fuel mileage, low power, and high exhaust temperatures. It was so bad, that a lot of customers chose to swap the MBN out for a different engine. Until people began to realize that they could just change the ECM program. Nowadays, the MBN “mechanical” platform ranks a close 2nd to a 6NZ. It’s an option for a powerful and reliable engine for those discerning owners who want to keep their classic trucks going strong.


In an effort to meet the EPA 2004 Emissions regulations, Caterpillar released the ACERT. More commonly referred to as the twin-turbo. It stands for Advanced Combustion Emissions Reduction Technology.

The first version of the ACERT was released in March of 2003 with a Serial Number Prefix of BXS. The BXS C15 had a relatively short production span as it was last produced in December of 2004, with a total of 39,000 units made.

Later, in March of 2003 Caterpillar also released the MXS serial number prefix. This MXS version of the C15 incorporated the engine brake housing and the variable valve actuators into the same housing. Whereas on the BXS they were 2 separate housings. The MXS was the most popular version of the ACERT C15 with 100,000 units produced between March 2003 and July 2006. Next up was the NXS serial number prefix.

The NXS C15 is exactly the same as the MXS, with no differences at all. The change in the prefix was because Caterpillar ran out of serial numbers under the MXS prefix. Caterpillar produced 33,000 NXS C15 Engines from July 2006 until April 2009.

Finally came the SDP prefix C15.

First released in January 2005, the SDP was Caterpillar’s final attempt to keep up with the ever-changing EPA On-Highway emissions regulations. By incorporating a Diesel Particulate Filter (DPF system). They also redesigned the turbochargers to have a ball bearing supporting the turbo shaft instead of brass bearings. This made the cost of a turbocharger replacement much more expensive. They also changed the fuel injectors and redesigned the oil cooler setup. Production of the SDP C15 ended in March 2009, with a total of 22,700 engines made. From technicians’ and owners’ standpoint, the SDP is like COVID-19, most technicians don’t know how to diagnose and treat it, and the
owners don’t want it.

When parts and machines fail, choose SRX to be your go-to source for all your engine parts, and remanufacturing needs. Whether it be a boost pressure sensor, a failed oil cooler, or your engine needs to be completely remanufactured. Not only just the Mighty C15, but many others.
To all of us here at SRX, there is nothing sweeter and more rewarding than the first time a freshly remanufactured engine takes its first deep breaths. When air mixes with dinosaur juice, and lets out its first throaty roars of a new life, and shakes the ground … dang! That just gave me chills thinking about it.

Charles Pratt is a Diesel Technician for Select Reman Exchange with 25 years of experience.

Illustrating the block of a Caterpillar C15 diesel engine.

Are you looking to buy a Caterpillar C15?

We often have completely remanufactured, long block, and used Caterpillar C15 diesel engines in stock. An extensive and competitively-priced inventory of parts is on our shelves! Give our Sales or Parts Teams a call or visit our Contact Us page.