13 Most Common 6.4L Powerstroke Problems & Fixes 3600

As much as the 6.4L Powerstroke included so many advantages over the later 6.0L version, it still has many setbacks. Lots of 6.4L owners know the struggle that these trucks bring with them. That being said, these trucks are still popular vehicles and are loved by many.

Thanks to the strong community that comes with owning these trucks, we can easily pinpoint most of the issues. The solution to many of these problems is usually to lift the cab so the mechanic can reach the engine easily. It takes time and effort so the bill can look a little pricey when it’s fixed.

Today, we are going to take a look into the main issues 6.4L Powerstroke owners face and how they can be fixed. So let’s dive in!

Editor's Note: Also, if you ever wanted to learn about how to drive an RV in the mountains, check out that article here.

The 13 most common 6.4L Powerstroke problems:

  • Poor fuel economy
  • Clogged diesel particulate filter (DPF)
  • Leaking radiator
  • Cracked blocks
  • Cracked pistons
  • EGR system failure
  • Oil dilution 
  • Cylinder washing 
  • Cracked up-pipes
  • Front cover cavitation
  • Fuel system failure and K16 injection pump self-destruction
  • Clogged engine oil cooler
  • High-pressure fuel pump wire chafing

If you have experienced any of these problems or believe that one of these could be the reason why your 6.4L Powerstroke is struggling, keep reading. We are now going to explain further what each problem exactly is and how you can make it right.

13 Most Common 6.4L Powerstroke Problems & Fixes 3600

1. Poor Fuel Economy

Even though many specifics make these 6.4L Powerstroke engines hugely impressive, they do have a slight issue when it comes to fuel economy. It was fitted with a diesel particulate filter that decreased the MPGs.

As we all know, driving in high traffic areas can also decrease MPGs. These both contribute to the increase of active regeneration cycles. These cycles are there to help clean the DPF and increase the EGTs. This means that diesel is being used for other purposes which ultimately brings down the fuel economy.

The Solution

If you want to improve the fuel economy of your 6.4L Powerstroke, it is going to cost you. There are a few mods that you will want to take a look at to up your fuel economy.

The three things that will change your 6.4L Powerstroke for the better are an aftermarket intercooler, a cold air intake, and a tuner. Here are some of our favorites on the market right now:

AirDog A6SABF494 Fuel Lift Pump (08-10 Ford 6.4L Powerstroke Preset @10Psi ii-4G)


This product clarifies your fuel for a cleaner burn whilst driving. The filtration system itself will significantly improve your fuel economy and also supply your fuel at a much more efficient flow.

This is an amazing aspect to add to your truck, especially if you are adding tuning to your vehicle too.

85400 Edge Diesel Evolution CTS2


This is a great mod to add to your 6.4L Powerstroke. It displays all the data you need to keep an eye on during your drive.

The sleek monitor is easy to read and the layout can be changed to suit your needs.


You may be tempted to go for the tuner and a straight pipe exhaust but you will want to avoid this option.

While this pairing can increase your MPG, it also deletes your emissions. This is a federal offense. Take a look at some of our recommended products instead.

2. Clogged Diesel Particulate Filter (DPF)

A well-known issue that 6.4L Powerstroke owners face is the clogging of the DPF system. This generally happens in higher mileage vehicles or when the regeneration process doesn’t efficiently clean the DPF. 

This can be a pricey part to replace on your truck. If you have experienced this issue, you need to ensure that it is properly fixed before using your vehicle. 

The Solution 

The main way to fix a clogged DPF is to replace it. You will want to look for a DPF that is easy to clean to prevent this from occurring again.

The best product we have seen out there for 6.4L Powerstroke owners has to be the below:

Bully Dog 70000 Diesel Particulate Filter


This product is a must if you need to replace your DPF. It increases the flow by 21% and is made from stainless steel. It is efficient and super durable.

It’s easier to keep clean too which will help it perform better over time.

3. Leaking Radiator

Unfortunately, the 6.4L Powerstroke has a poorly designed radiator. It is well known for its leaks throughout the trucking industry. The main issue is that the plastic on the end of the radiator starts to separate causing the coolant to pour out. Look out for that puddle of coolant under your truck as the first warning sign.

We know that this is a common issue with the 6.4L Powerstroke, so we know what works best to eliminate the problem.

The Solution 

Unfortunately, you can’t really fix the leaking radiator. As much as there are products out there to mend your radiator, we don’t recommend them.

Your best bet is to completely replace the truck’s radiator. 

Mishimoto MMRAD-F2D-08V2 Performance Aluminum Radiator Compatible With Ford 6.4 Powerstroke 2008-2010


The best radiator that you will find widely available is this Mishimoto model. This is specifically designed to fit the 6.4L Powerstroke so you know you’re getting the best. It is manufactured with a top and bottom core support plate which prevents further damage to the radiator. 

This is the most durable radiator you will find out there. If you’re still worried, you could add on a radiator support bar like the one we have linked to below:

Mishimoto MMUS-F2D-08 Upper Support Bar Compatible With Ford 6.4 Powerstroke 2008-2010 Stealth Black


This is the same brand as the radiator we have linked to so it is the most compatible option. It is made to protect against any force or bumps to the front end of your truck.

There will also be less stress put onto your radiator which will mean that your cooling process will be much more efficient.

4. Cracked Blocks

If your 6.4L Powerstroke has a cracked engine block then this may be another fault that will cost you. The main reason why this is so difficult to repair is that the engine block is manufactured from cast iron, not steel. It is hard for many people to even begin to fix.

Even when you believe you have fixed your cracked engine block, you could still be looking at further repairs. This is because as the temperature changes, the metal will begin to shrink and enlarge. This opens up the crack once again meaning that further work is needed. 

The Solution

The best thing you can do is to replace the engine block. This is ultimately the most expensive way however it will ensure that the crack is eliminated. 

For the best advice, we recommend taking your truck back to the manufacturer’s garage for further inspection. They will be able to replace the engine block with the most efficient parts.

5. Cracked Pistons

Usually, the cracks will start to form around the fuel bowl. The pistons on the 6.4L Powerstroke have been poorly designed so unfortunately, this is a common problem. It is more likely to occur in a truck with higher mileage but don’t go crossing that issue off your list if you have lower mileage on your vehicle. 

As always you should keep this in mind when carrying out your weekly checks to your truck. If you leave these cracks too long then they can start to cause worse problems. 

Leaving cracked pistons too long can lead to melted injector tips which is something any Powerstroke owner will want to avoid.

The Solution 

Unfortunately, you can’t repair a cracked piston. You will have to replace it.

It is a more expensive part to replace so be prepared to face those charges when you take it into the garage. 

6. EGR System Failure

The 6.4L Powerstroke is known to have two EGR coolers. This is all well and good until one or both of them fail. Why do they fail? Well, if your EGR system fails it is because the EGR cooler has become clogged. 

When this happens, the exhaust gases cannot be filtered through the EGR system. This can cause a lot of problems going forward so you will want to add some modifications to your vehicle to get the best out of it.

The Solution 

The main modification that you can add to your 6.4L Powerstroke is a coolant filtration system. Adding one of these to your truck can help improve your coolant quality whilst also prolonging its lifetime. 

As well as investing in a coolant filtration system, please remember your regular maintenance checks. Keep a close eye on your coolant levels and change them as much as is needed. 

Our top coolant filtration system is the below product:

Sinister SMC-COOLFIL-6.4 6.4l Ford Powerstroke Coolant Filtration Kit


This system is made especially for the 6.4L Powerstroke. It is ideal to extend the life of your coolant safely.

It is also a leakproof design which is another fantastic reason to add this to your truck.

7. Oil Dilution

If you have ever gone to change your oil on your 6.4L Powerstroke, then you will know how messy it can get. When you start emptying the oil, you may have been surprised to find even more oil than you imagined.  This isn’t actually more oil, this is oil dilution. 

This happens when the 6.4L goes through active regeneration. The diesel doesn’t inject into the exhaust stroke fast enough so it travels into the exhaust stream. This spikes the truck’s EGTs and also burns hydrocarbons that are found in the DPF.

This can lead to a lot more wear and tear on your vehicle over a shorter period. But don’t worry, we know how to fix this!

The Solution 

As always, you should check your oil levels once a week minimum. If you are going on longer journeys, then take more regular readings. Most 6.4L Powerstroke owners aim to change their oil every 5000 miles, so aim for that. It makes the engine work a lot smoother.

Don’t go for the cheapest option when buying new oil. To keep your truck in the best condition, go for high-quality diesel engine oil. Ensure that it is compatible with your vehicle before clicking that buy now button. Here is our favorite oil to keep up with your truck’s maintenance!



This oil will keep your engine performing its best over time. It is one of the best oils for the 6.4L Powerstroke. This product is suitable for vehicles situated in parts of the country over 20 degrees Fahrenheit. 

If you live in a colder climate, then maybe check with your local garage for their best recommendation. If you’re still struggling, your user manual will also provide you with a good suggestion.

8. Cylinder Washing

Another problem that is common for the 6.4L Powerstroke is cylinder washing. This usually begins to happen when the engine oil is diluted. The fuel is injected way too late in the exhaust which pushes it to wash the cylinder. 

The cylinder is coated in a thin layer of oil which protects it and keeps it running. This washing of the cylinder dilutes the layer of oil and can lead to further problems.

The Solution 

To keep the cylinder in its best condition, regular checks are advised to prevent any further problems. Add this step into your maintenance checks and you will be prolonging the life of your vehicle. 

Another way to solve this problem is to rebuild the carburetor. If you believe that this is the way forward for your vehicle, we advise you to speak it through with a professional before carrying out the repairs.

9. Cracked Up-Pipes

Cracking of the up-pipes is another well-known issue on the 6.4L Powerstroke. It happens when the expansion joints get worn and can result in a loss of power. If you suspect your truck may have this problem, keep an eye out for the following:

  • Soot on the firewall 
  • Soot on the hood 
  • Soot in the engine compartment
  • Hissing noise coming from under the hood

If you are experiencing any of the above, we can help you out with some killer recommendations!

The Solution 

If you have confirmed that your up-pipes are cracked, your only choice is to replace them. Many people would rush to get the same factory set of pipes, but if you want some great performing pipes, you may want to look elsewhere. 

There are a wide variety of up-pipes available on the market. They can be much more durably made, have lifetime warranties and keep your vehicle running super smoothly. We are so kind to you that we are going to share our top up-pipes!

2008-2010 Ford 6.4 Powerstroke Heavy Duty Up Pipe Set F250 F350 F450


These stainless steel up-pipes are durable and will last you a long time. They are the perfect replacement for any cracked pipes already installed on your truck.

These up-pipes are specifically designed for the 6.4L Powerstroke so you know there will be no problems when it comes to fitting them.

10. Front Cover Cavitation

Another reason to keep up with your oil checks is to ensure that the front cover isn’t showing any leaks. Frequent checks of your dipstick can pinpoint leaks just about to occur before they turn into anything more severe. 

The main reason that this is a common problem for the 6.4L Powerstroke is down to the cavitation. Most 6.4L Powerstroke owners who have had this issue tend to experience the problem around the water pump. 

Due to this, we always recommend checking that area during your weekly maintenance checks. 

The Solution 

The best thing you can do is to get yourself a coolant filtration system and continue regular checks of your oil levels. If you need to replace your front cover, it can be quite an expensive repair so preventing the problem in the first place is always a good idea.

To replace a front cover, go directly to a Ford garage for the best advice on which parts to choose.

11. Fuel System Failure and K16 Injection Pump Self-Destruction

It is so important to regularly drain your fuel-water separator. Lots of 6.4L Powerstroke owners are aware that these things love to clog which can lead to a very hefty invoice from your garage. So how does this happen? We hear you ask…

If there are problems with the fuel-water separator, the main thing that could have happened is that the water and fuel have mixed to form a thick substance. This then cannot be filtered through the system correctly and completely clogs the drain valve. 

This results in poor quality fuel and a system that is full of rust. Now, this is not good news for your K16 injection pump. If this poor quality fuel runs through it, the system will begin to send metal pieces to your injectors. It will destroy your fuel system completely and cost you a ton of money.

The Solution 

This truly sounds like a nightmare, right? To keep this from happening to your vehicle, we recommend that you drain your fuel separator every fortnight. Add it into your maintenance routine and you will help prevent this from happening. 

If you’re still unsure, you could also look to get a fuel lift pump system. Adding this to your truck will also improve your fuel economy and give you a much better performing vehicle. Here is our top recommendation:

AirDog II-4G, DF-165-4G Fuel System compatible with 2008-2010 Ford 6.4L with Ohio Diesel Parts Sump Kit (A6SABF494)


This is a fantastic bit of kit that is suitable for trucks with a horsepower of 500-700.

Adding this to your 6.4L Powerstroke will help to keep your fuel-water separator in check.

12. Clogged Engine Oil cooler

This is another top problem that many 6.4L Powerstroke owners face. The engine oil cooler gets clogged which the breakdown of the coolant clogs up the passage of the oil cooler. This means that the coolant can’t get through. 

The issues that a clogged engine oil cooler causes are the high engine oil temperatures and less coolant to the EGR system. The engine can quickly decline so you will want to act fast.

During your maintenance checks, keep an eye on your coolant and engine oil temperature. Anything over a 14-degree split may mean that your oil cooler is on its last legs. 

The Solution 

If this happens to your truck, you’re going to want to replace it. Replacing the engine oil cooler will keep your truck in check for a maximum of 75,000 miles. Our top pick has to be the below:

Mishimoto MMOC-F2D-08 Replacement Oil Cooler Compatible With Ford 6.4L Powerstroke 2008-2010


This is a leak-free piece of equipment that will breathe a new life into your truck. The oil cooler has been manufactured especially for the 6.4L Powerstroke so installation should be a breeze.

This also comes with a lifetime warranty.

13. High-Pressure Fuel Pump Wire Chafing

If you have one of the earlier models of the 6.4L Powerstroke then you risk the issue of chafing to the high-pressure fuel pump wire. The day-to-day movement of the vehicle can cause the wires to become exposed over time. 

Now, if this happens to you, you’re going to want to get it fixed quickly. If you leave it too long, you risk even further damage being done to your truck. Many people have experienced the shorting of their high-pressure fuel pumps. 

If you’re unsure what this is, it’s expensive. Thankfully, we know exactly what you need to do to fix this problem.

The Solution 

Ford was made aware of this problem after the earlier models of the 6.4L Powerstroke were released. Thankfully, they corrected the issue by adding a covering to protect the wire harness in the later models. 

The later models of these trucks are the best sellers. We’re talking about the 2009-2010 models. However, if you do have an earlier model, have no fear. Ford does sell a replacement harness that comes equipped with a protective covering.

Cover - Fuel PU


This has everything you need to get your wires protected again.

We have to praise Ford for taking the feedback from the earlier models and working quickly to release an improved model in 2009.

Why the 6.4L Powerstroke is still the right truck for you

Now that we have gone through some of the most common 6.4L Powerstroke problems, you may be put off from getting one. Don’t let us put you off! They are still great vehicles and improved vastly from the earlier 6.0L Powerstroke. 

As long as you’re willing to treat this vehicle with the care it deserves, you will enjoy your time with the 6.4L Powerstroke. With any type of vehicle, problems will sometimes arise. But thanks to our helpful guide, you can relax knowing exactly how to fix those issues. 

Modifying your vehicle can bring excitement to your life on the road, but don’t go overboard. Excessive modifications can reduce the life of your truck. Keep any modifications for essential work needed and you will be fine. 

We hope that you have found some tips and tricks that will help keep your 6.4L Powerstroke on the road for longer. Enjoy that ride!