Cummins ISX Engine History and Cylinder Heads

Categories: Cylinder Head Tips

For over 15 years the Cummins ISX engine has been one of the top-rated diesel truck engines in North America. The ISX engine replaced the previous N14 series, which was discontinued due to updated EPA emissions regulations. Today, we’re going to head back in time to learn more about the history of the Cummins ISX engine as well as common issues with the engine and its cylinder heads.


Cummins ISX Engine History

First debuting in 2001, the Cummins ISX engine replaced the N14 series, which had been around for many years and was an excellent diesel engine. This engine had to be discontinued as it no longer passed EPA emissions regulations, which made it out of date for its time. Initially, the Cummins ISX engine was going to be called the Signature series, as it was such an advanced addition for the company. The engine is now used for on-highway needs, whereas the QSX engine also offered by the company was designed for off-highway use, such as with the marine and agriculture industries.


What Does ISX Cummins Stand For?

ISX stands for Interact System, which indicates that this engine from Cummins is for on-highway use. QSX is the other option they offer, which is an appreciation for Quantum System and is used within industrial applications, pumps, and generators.


Cummins ISX15 – What Does 15 Stand For?

ISX15 was first offered in 2010, and started being phased out from 2016 through to 2020. The X15 replaced this engine, which is one of the current options on offer. The 15 refers to the displacement of the engine, which comes in at 14.9 L with this model.


How Many Miles Will A Cummins ISX Engine Last?

When choosing a new heavy duty truck engine, it’s important to consider how long it will last. The Cummins ISX has been known to last for over 500,000 miles in some cases, which is incredible for this type of engine. The length of time this engine lasts is one of the top benefits of it. In fact, this engine can even run for up to 15,000 miles between filter and oil changes. The engine usually comes with a base warranty of two years or 250,000 miles, but this can be increased up to five years or 500,000 miles with the extended coverage option.


How Many Miles Per Gallon Does a Cummins ISX Get?

The number of miles per gallon a Cummins ISX engine gets will depend on a number of factors, but it typically comes in between 7 and 10 miles per gallon. If you are experiencing lower levels, there may be an issue with the engine, so you’ll certainly want to get it checked out to ensure there are no faults or mechanical issues.

What Trucks Use Cummins ISX Engines?

Many truck manufacturers use the Cummins ISX engines, thanks to the many benefits they offer. Some of the most popular trucks that use this type of engine include the Freightliner Corp. PX12564 Sleeper, Freightliner Corp. Cascadia Sleeper, International ProStar+ 122 6X4 Sleeper, and Kenworth Motor Truck Co. T680 Sleeper. This engine is widely used within both vocational and highway trucks, offering power options from 430 hp up to 620 hp.


How Much Does a Cummins ISX Engine Cost?

The price of a Cummins ISX engine will depend on a number of factors, but a new ISX15 typically comes in at around $24,000. Of course, you will find there are a number of different elements you can adjust on the engine, which may increase the price significantly. Used engines are likely to be a little cheaper, but you’ll want to ensure they don’t have any problems or too much wear and tear to make this engine a worthwhile purchase.


What Are Common Problems With a Cummins ISX15 Engine?

While there are many benefits of this engine, you’ll need to be aware of some of the common issues that are experienced with the Cummins ISX15. One of the most frequently reported issues with this engine is with the EGR valve, which is prone to leaks and issues. You might also find that you have a flattened camshaft, as every model of the ISX has experienced problems in this area over the years.

Dropped cylinder liners and issues with the cylinder head are another troublesome area that you’ll want to keep an eye on when using this engine over an extended period of time. Lastly, be sure you keep an eye on the turbocharger, timing wedge, and EGR to avoid major issues or breakdowns.


How Much Do Cylinder Heads For a Cummins ISX Engine Cost?

As we shared above, one of the most common problems with the Cummins ISX engine is with the cylinder head. If you do need to replace the cylinder head, then you’ll want to keep in mind that this isn’t the cheapest of parts to purchase. Expect to pay roughly $3,750 for a new cylinder head, which is a fair percentage of the overall cost of this engine when it’s purchased new. This price is for an engine with a single overhead camshaft. If you have a cylinder head with two camshafts, make sure you upgrade to the correct part for this type of engine. If you do need this replaced, you could opt to DIY it or contact a professional if you are unsure about how to complete this job.

The Cummins ISX engine has been used in many of the world’s top trucks over the years, thanks to how long-lasting and low-maintenance the engine typically is. You’ll want to make sure you keep on top of maintenance of this engine and your vehicle to avoid issues in the future, so that you can enjoy years of use and thousands of miles from the Cummins ISX. If you do need to replace the cylinder head, keep in mind that this can be a very costly procedure, so ensure the engine is in good condition still to make this a worthwhile upgrade.


Purchase Cummins Engine Cylinder Heads

For more information on purchasing cylinder heads for a Cummins engine, please check out the products links below:



If you own or maintain a truck with a Cummins engine and need to buy new or refurbished cylinder heads, then we encourage you to call us at 800-572-1963. We would love to work with you over the phone to select the correct head for your Cummins engine. You can see some of our Google reviews at We look forward to helping you with new or refurbished Cummins engine cylinder heads. The casting number on your diesel engine or existing cylinder head will help us determine the compatible head(s) for your specific vehicle. We look forward to hearing from you.