The 6.4L Ford Powerstroke engine’s release in 2008 marked a decisive shift from its predecessors, the 6.0L, in several ways. For one, it marked the debut of the CRI common-rail injection system in the Powerstroke series. This was an improvement over the old HEUI (Hydraulic Electronic Unit Injector) design that caused tough starts, leaking high-pressure oil, in favor of a system that reduced emissions, and made the engine quieter, while also improving power output. Second, it was the first Power Stroke to implement a diesel particulate filter (DPF) to reduce emissions from the exhaust. Third, it featured a new exhaust gas recirculation (EGR) system to further control emissions. The engine was released at a time when emissions regulations were becoming very strict, making these changes necessary to ensure legal compliance without giving up on power output.

While the 6.4 looked promising initially, regular use revealed that it quickly runs into a host of very expensive issues, leading to Ford releasing the 6.7L just over two years after the formers release. Prominent issues include leaking radiators, poor fuel economy, cracked pistons, etc. If you own a 6.4L, these problems, among others, could easily burn a hole in your pocket. Thankfully, this article discusses the 6.4L and its various issues in detail, shedding light on how you can properly maintain your diesel engine to avoid problems and what to do when you inevitably run into one.

The Problem with the 6.4L Power Stroke Engine

As we’ve mentioned, the 6.4L Navistar engine came with many changes over its predecessor, the 6.0L Navistar engine, which was intended to improve its power generation while abiding by new emissions guidelines. Unfortunately, many of the changes Navistar made contributed to the problems this engine suffers from and Ford disliked.

On the bright side, the 6.4L is a powerful engine, generating around 350 horsepower and 650 pound-feet of torque. This was a big reason why, initially after launch, the 6.4L was very successful and popular. However, this output comes at a big cost considering the problems the 6.4L suffers with along with its poor fuel economy. Some Ford truck owners have, fortunately, not experienced many problems with their 6.4L and those that haven’t still swear by it.

Many of these problems stem from the DPF Diesel Particulate Filter used by the engine. Essentially, the DPF collects excess soot which is ultimately burned off by the electronic control unit (ECU) going into a regeneration mode when the filter gets clogged by sensing a differential pressure upstream vs. downstream from the DPF. However, the high temperature at which the ECU burns the soot in the filter causes internal temperatures to skyrocket, resulting in a host of issues—including cylinder overheating or engine parts melting off and cracking. Among the parts that fail often due to this are the 6.4L pistons, which are anyway vulnerable to damage, especially after the engine crosses the 200,000-mile mark. The damage can then spread to your injectors, which might also experience some melting and require replacement. To make things worse, piston cracking can happen at any time, making it a constant worry for 6.4L owners.

The DPF can also lead to oil dilution since the running of the exhaust system can lead to the fuel slipping through the pistons rings and cylinder walls and into the oil, thereby impacting its lubricating function. Moreover, the high temperature at which the exhaust regeneration mode burns the soot into ash in DPF is also a big factor behind the 6.4L’s poor mileage.

Other problems afflicting the 6.4L include radiator cracking from the engine vibrations, which can result in engine coolant leaks. Lack of sufficient coolant can make the engine overheat and severely damage it in the process. The exhaust system weight and bulkiness ancillary device is also a strain on the exhaust pipes, which can also crack or leak due to the high temperatures involved.

How to Get the Most Out of Your 6.4L Power Stroke Engine

The 6.4L Powerstroke Engine has become notorious for running into problems once it reaches the 150,000-200,000 mile range, but there are some things you can do to improve its longevity and drive down costs in replacements and labor.

The first, and most controversial, way to make your engine more reliable is to delete the DPF from your engine, either with an aftermarket exhaust pipe or with a delete pipe. Keep in mind that modifying the emissions systems of your vehicle is illegal in every state in the US and can rack up some hefty fines if and when discovered. Regardless, it is an option that can be pursued if your heart is set on a 6.4L. The second way is to simply maintain your engine regularly and thoroughly. Your maintenance schedule should depend on how extensively you use the vehicle carrying the 6.4L and the kind of operating conditions, such as towing, off-road use, driving on low speed for long time periods, etc., it is subjected to.

However, regardless of how you use your vehicle, Ford’s own maintenance schedule that they recommend following is not regular enough, and the 6.4L will require more frequent maintenance than it suggests. Like with other vehicles, there are standard steps to follow to properly maintain your engine. This includes changing its engine oil, fuel, and air filters, draining the fuel-water separator, flushing the cooling system, replacing the automatic or manual transmission fluid, along with replacing the front and back differential fluids after the engine has covered a certain number of miles.

For the 6.4L, you’ll want to take Ford’s recommendations and halve most of them. For example, the Ford manual suggests changing your oil and oil filters every 10,000 miles for normal users. However, you’ll want to do it every 5,000 miles instead. Similarly, it says that you’ll want to flush the cooling system every 100,000 miles, but you should do it every 50,000-60,000 miles instead. For services such as changing the front differential fluid, the manual recommends doing it after covering 150,000 miles, but the real number is closer to 50,000 miles. Lastly, the automatic transmission fluid replacement recommendation for 30,000 miles can be followed as is. Sticking to a more regular maintenance schedule along these lines will help you dramatically reduce potential issues with the 6.4L and enjoy its good parts better.

These are some of the more basic things to take care of when servicing your car. However, more experienced users might want to go a step further and regularly inspect for damaged parts such as pistons, gaskets, belts, connecting rods, hoses, etc., and replace them whenever necessary. You’ll also want to keep an eye on the EGR system. The health of the EGR valve or parts when hunting for possible issues. For improved performance, adjust and balance the fuel pressure along with the air-to-fuel ratio.

Consider Dieselogic for Replacing Your 6.4L Engine’s Parts

As we’ve seen, the 6.4L can run into a host of very expensive issues because of the way it has been designed. While regular and proper maintenance can help you avoid issues for a while, most users are bound to run into some of the problems we’ve discussed at some point. When that happens and you’re in need of replacement parts, or your engine simply isn’t working the same way it used to when you purchased it, consider Dieselogic’s range of performance parts, injectors, glow plug, fuel pump kits, lift pumps, and related products.

While most of the parts we offer are new, some, like our injectors, are remanufactured/ manufactured again grade quality. However, this doesn’t mean they’re in any way worse than new parts. All parts sold by Dieselogic are rigorously tested for quality control and customer safety to ensure compliance with the highest market standards for performance, while being cheaper than new parts. Any component that doesn’t meet benchmarks like OEM specifications is replaced with other new or manufactured again parts.

Rest assured, Dieselogic has been doing this for a very long time (over fifty years). We have five decades of experience being a part of the diesel fuel systems remanufacturing industry, all of which have been spent honing our craftsmanship and offering the best customer service to our clients. We also strive to offer the best prices on the market, and if you find a price for parts lower than ours, contact us and we can discuss matching our price to the one you’ve been offered. All of our work is done right here in the US, which includes our customer service, ensuring that we don’t outsource any of our work and handle remanufacturing ourselves. Call us today to find out more about our offers, services, or discuss issues you’re facing with your vehicle so that we can recommend an appropriate remedy.


The 6.4L was supposed to improve many of the issues that plagued its predecessor, the 6.0L, and comply with increasingly strict emissions standards without compromising on power output. However, design flaws and an unpredictable DPF system have meant that the engine frequently runs into issues such as cracked pistons, leaky radiators, oil contamination, etc. In this article, we’ve discussed how you can avoid facing these issues by regularly and carefully maintaining your engine. However, if you do run into issues with parts that require replacement, we at Dieselogic would be delighted to help you repair your 6.4L. We offer a range of parts that tend to fail in the 6.4L at reasonable prices that you won’t find elsewhere. But, if you do, call us and we’ll match it!