6.4 Power Stroke Diesel Engine Problems
The 6.4 Power Stroke only had a few short years in Ford trucks. It’s also the last Ford diesel from International as Ford designed and built the 6.7 Powerstroke in house. Ford 6.4 diesel engines make a solid 350hp and 650tq from the factory. Respectable numbers for the era the 6.4 Powerstroke was released. Some also consider the 6.4L a reliability improvement over the previous 6.0 diesel engine from Ford. However, no engine is perfect and there aren’t any exceptions here. In this article, we discuss a few common problems on the 6.4 Power Stroke and overall reliability.
Ford 6.4 Powerstroke Common Problems
A few of the most common issues on the 6.4 Power Stroke engine include:
- Oil cooler
- Fuel dilution
- Cracked pistons
We’ll dive into each of these problems throughout this post and discuss them in greater depth. It’s important to note – simply because we’re calling these faults and failures common doesn’t necessarily mean they affect a large percentage of 6.4 diesel engines. Rather, they’re a few of the most common issues. Also, failures we don’t discuss in this article can and do happen.
That said, let’s move into the common 6.4 Powerstroke problems listed above. We will also finish the post with some overall thoughts on Ford 6.4 reliability.
1) 6.4L Power Stroke Radiator Leaks
6.0 Power Stroke engines occasionally developed coolant leaks due to head gasket failures. However, if you notice a puddle of coolant under the 6.4 Powerstroke the radiator is the likely culprit. The plastic ends of the radiator tend to crack or separate and develop leaks. It’s without question one of the most common issues to pop up on the Ford 6.4 diesel.
If too much coolant is lost the 6.4 Power Stroke may begin overheating rapidly. In this case, it’s important to shut the engine down quickly to avoid further damage. Either way, a radiator leak should be treated as an urgent and important repair. This is especially true if you have a severe radiator leak on the Ford 6.4 Powerstroke.
Ford 6.4 Diesel Radiator Leak Symptoms
Symptoms of a radiator problem on the 6.4 turbodiesel include:
- Visible leak
- Steam from engine bay
It’s normally pretty straight-forward to notice a leaking radiator on the Ford 6.4 engine. Look for any visible leaks under the truck. You may also notice steam from the engine bay if coolant is leaking onto hot parts. Lastly, overheating can occur rapidly if the coolant loss is severe enough.
6.4 Powerstroke Radiator Replacement
If you intend to keep your 6.4 diesel for the long-term we highly recommend upgrading the radiator. Mishimoto radiators are a common option for the 6.4 Power Stroke. However, at nearly $900 they’re certainly not cheap. You can also go for the OE radiator or alternative aftermarket options. Those can set you back about $200-500 depending on the exact radiator. Labor is generally about 2 hours for the radiator so add in a couple hundred bucks for that. All in all, replacement costs for the 6.4 diesel radiator can run about $400-1000+.
2) Ford 6.4 Turbodiesel DPF Clogging
Diesel particulate filters (DPF) have been problematic parts on many modern diesel engines, and the 6.4 Powerstroke isn’t an exception. The Ford 6.4 is the first diesel truck from Ford to use a DPF. A DPF is meant to capture particulates before they exit the exhaust. This helps improve emissions, however it also leads to headaches with the filter clogging.
It’s a common problem on the 6.4 Power Stroke, which is why some choose to delete the DPF. It can cause a number of issues once the filter becomes too clogged. DPF clogging is also harder on the engine and turbo. This is because a clogged Ford 6.4 DPF can cause excess back-pressure. The engine then has a harder time getting rid of hot exhaust gases, which can increase stress on many parts.
6.4L Powerstroke DPF Clogged Symptoms
A few symptoms of a clogged DPF on the Ford 6.4 diesel include:
- Power loss
- Long crank
- Fault codes
As the filter clogs the 6.4 Power Stroke will experience a lot of extra back-pressure. This often results in power loss as the engine struggles to remove exhaust gases quickly. You may also notice long cranks or receive fault codes indicating an issue.
Ford 6.4 Diesel DPF Fix
If you’re DPF is clogged there are a few viable solutions. Often pulling the filter out and cleaning it is the cheapest solution. Though, that won’t stop the DPF from potentially clogging again shortly after. That’s a big reason many 6.4 Power Stroke owners decide to completely delete the DPF. However, deleting the Ford 6.4 DPF may cause legal and emissions testing concerns. Aftermarket diesel particulate filters are another option, but they can be pretty pricey.
3) 6.4 Power Stroke Up-Pipe Problems
The exhaust up-pipe is another common problem on Ford 6.4 Power Stroke engines. Expansion joints on the up-pipes are prone to cracking, especially with age and mileage. The cause of the issues usually boils down to vibration and heat cycles. Up-pipes are a pretty simple but important part of the 6.4 Powerstroke exhaust system.
When the joints crack they can cause excessive soot in the engine bay. You’ll also likely notice a loud hissing noise from the engine bay. This is a pretty simple problem on the 6.4 diesel, so we’ll leave it at that.
Ford 6.4 Up-Pipe Symptoms
Symptoms of up-pipe problems on the 6.4 Power Stroke typically include:
- Hissing from engine bay
- Excessive soot in engine bay
- Power loss
When the joints crack and begin leaking you’ll typically hear a hissing sound and notice lots of soot building up in the engine bay. You may also experience some power loss.
6.4L Powerstroke Diesel Up-Pipe Replacement
It’s a good idea to upgrade to aftermarket pipes once the stock ones give out. Otherwise, you may be back in there fixing the same problem a few years down the road. You can find some solid options for the 6.4 diesel like this for under $400. Labor can be a hassle so it’s definitely a good idea to upgrade to up-pipes that won’t run into the same problems.
4) Ford 6.4L Diesel Oil Cooler Issues
As with the DPF, oil coolers are another problematic area due to clogging. Sometimes EGR failures are incorrectly diagnosed, and the real issue at hand is a clogged oil cooler. The 6.4 Powerstroke oil cooler is responsible for cooling the engine oil – exactly as the name sounds. It uses coolant to cool the oil, and those passages may become blocked over time. When this occurs the engine oil temps may rise higher than normal.
Keep an eye on your engine oil and coolant temperatures. The two should typically remain within about 15 degrees of each others. If you notice the 6.4 Power Stroke temps are deviating too much chances are the oil cooler is on its way out. There’s no way to clean the oil cooler once it clogs, so complete replacement is usually required.
6.4 Power Stroke Oil Cooler Symptoms
Look for the following symptoms that may indicate the Ford 6.4 diesel oil cooler is having problems:
- Oil/Coolant temp deviation
- Oil overheating
As mentioned above, the oil and coolant temperatures should remain within 15 degrees of each other. If the oil is consistently getting too hot then the 6.4 oil cooler may be too clogged to operate effectively.
Ford 6.4 Oil Cooler Replacement
The OEM 6.4L Powerstroke oil cooler runs around $350-500. However, if you replace with the OEM part you may be replacing it again in another 50,000 to 80,000 miles. They sometimes last longer, but it’s a risk you must be willing to accept. Otherwise, Mishimoto offers an oil cooler upgrade for a mere $150. It also comes with a lifetime warranty for the 6.4 diesel. That would likely be our first pick.
5) 6.4 Power Stroke Fuel Dilution Problems
Active regeneration is the process that attempts to help keep the DPF clean. The Ford 6.4 diesel does this by injecting fuel during the exhaust stroke. This allows the fuel to exit the cylinder and flow downstream in the exhaust. This helps keep the DPF cleaner and burn off harmful emissions. However, there’s an inherent flaw to the way Ford designed this system.
Some engines use an extra injector to spray fuel directly into the exhaust stream. The 6.4 Power Stroke injects the fuel into the cylinders on the exhaust stroke. This allows small amounts of fuel to deposit on the cylinder walls where it can then contaminate the engine oil. Some fuel dilution of the oil is OK and shouldn’t cause any harm.
However, if too much fuel mixes with the oil that can affect the oils ability to properly cool and lubricate the engine. This could lead to premature wear and tear on the 6.4L diesel internals. Not a good thing for engine longevity.
How to Avoid Ford 6.4 Fuel Dilution
There really aren’t any symptoms or specific fixes for the fuel dilution problems on the 6.4 Power Stroke. Instead, we’ll discuss a few ways to minimize fuel dilution and reduce the risk of it causing premature wear.
First, avoid excessive idle time as the cylinders cool down during idle. This increases the likelihood of fuel sticking to the cylinder walls and diluting the oil. It’s also a good idea to allow the engine to warm up before subjecting the 6.4 diesel to heavy loads.
Lastly, we recommend having an oil analysis done from time to time. It’s pretty cheap and will tell you just how much fuel is mixing into the oil. You can then adjust your oil change intervals to account for the fuel dilution.
6) Ford 6.4 Diesel Pistons Cracking
This is one of – if not – the least common 6.4 Power Stroke engine problems on the list. However, it’s one of the more serious issues so cracked pistons are worth the quick mention. This is most common on higher mileage trucks, especially north of 200,000 miles. However, piston failures can and do occur on lower mileage Ford 6.4 diesel engines.
6.4 Power Stroke pistons simply aren’t that durable. That’s not to say they’re terrible, and this problem may be blown out of proportion to some extent. Nonetheless, the “fuel bowl” in the piston is typically where the cracks first develop. They can then get much worse and lengthen across the entire piston. If it’s bad enough you can begin losing parts of the piston and causing catastrophic engine damage.
6.4 Powerstroke Piston Failure Symptoms
A few symptoms that may indicate piston issues include:
- Excessive smoke
- Loss of compression
- Power loss
Piston failures on the 6.4 Power Stroke can result in excessive white smoke from the exhaust. You may also notice a loss of compression if you perform a compression test. That can in turn lead to power loss and misfires if the cylinder isn’t building proper compression.
Ford 6.4L Piston Replacement
Since pistons are an internal part of the 6.4 diesel it’s not a cheap replacement. The engine will need to be opened up so it’s a very labor intensive job. There’s also somewhat of a conundrum on higher mileage 6.4’s. If you’re going to open up the engine to replace one faulty piston you’re likely looking to keep the truck for a while longer. At that point, it likely makes sense to replace all 6 pistons and some other parts while you’re in there.
Of course, that can add a lot of costs especially if you plan to upgrade a few things in the engine. It’s a good idea to do this stuff if you intend to keep the 6.4 Power Stroke running. Otherwise, a cracked piston very well may not be worth the cost.
Ford 6.4 Powerstroke Reliability
How reliable is the Ford 6.4 Power Stroke turbodiesel? This is a tough one to discuss. Some swear by the 6.4L diesel and claim it was a massive improvement over the previous 6.0 Powerstroke. Others have had terrible experiences with the 6.4 and dub it one of the least reliable Ford diesel engines. Reality likes falls somewhere in between the two.
The 6.4 Power Stroke isn’t alone here. It was made in an era where emissions equipment was becoming more and more complication. We skipped over a few of those problems in this post that may also be considered common. Nonetheless, a lot of failures like DPF, EGR, oil coolers, etc are due to emissions laws and additional equipment required. A lot of this can be deleted to make the Ford 6.4 diesel more reliable. Though, the 6.4 Powerstroke also suffers from a few unrelated issues like radiators, pistons cracking, HPFP wire chafing, etc.
That said, we’ll give the 6.4 Power Stroke average remarks for reliability. It’s certainly not as reliable as some of the older legends like the 7.3 Power Stroke or 5.9 Cummins. However, it’s a totally different ball game now days with all of the emissions stuff so it’s not a totally fair comparison.
Ford 6.4 Diesel Common Problems Summary
Ford only used the 6.4 Powerstroke for two short years as they quickly introduced their own 6.7L Power Stroke that was built in-house. The 6.4L diesel produces a solid 350hp and 650tq straight from the factory. On paper, the numbers look solid for the era the engine was released. The 6.4 also had the responsibility of following up the 6.0 Power Stroke which did not have a good reputation by any means.
Unfortunately, the 6.4 Powerstroke hasn’t earned the greatest reputation, either. Some consider it a great improvement over the 6.0 while others claim the 6.4 is just as bad. It’s a different era with all of the strict emissions requirements. As such, a lot of the problems with the 6.4 Power Stroke turbodiesel begin with the emissions stuff. However, the engine does also suffer a handful of other issues unrelated to emissions tech.
All that said, the 6.4 Power Stroke earns average remarks for reliability. Sure, it’s not on the same level as the 7.3 PS or 5.9 Cummins, but it’s a different era. Maintain your 6.4 diesel well and upgrade stuff as problems pop up. It might cost a little money, but with the right upgrades you can build the 6.4 Power Stroke into a much more reliable engine.
What’s your experience with the Ford 6.4 diesel?
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