You know, I thought by now we might be done talking about Powerstroke engines, but once again here we are talking about them. This time around though want to change things up, and instead of looking at the Powerstroke engines that are known to be problematic like the 6.0L and 6.4L, I want to do something else, and that’s looking at everything wrong with the 6.7L Powerstroke.
If you didn’t already know, the 6.7L Powerstroke is the most recent Powerstroke engine offered in Ford super duty trucks. The Powerstroke lineage starts with the 7.3L, then the 6.0L, then 6.4L, and now the 6.7L. So, get buckled in and comfy, let’s cover every major issue on the 6.7L Powerstroke and what causes them.
Where Did it Come From?
Real quick for those who don’t know the whole Powerstroke story, I want to cover why Ford developed the 6.7L Powerstroke and why it’s so much different than the Powerstroke engines that came before it.
Previous Powerstroke engines were built by Navistar International. The 7.3L, 6.0L, and 6.4L were all built by Navistar rather than Ford themselves. Navistar put the engines together on Ford’s behalf and then Ford paid them for the motors, put them in their F series trucks, and that’s that.
The 6.0L Powerstroke was developed and replaced the 7.3L because of one thing: emissions standards. The government and the EPA specifically, make it increasingly difficult to pass emissions standards, by raising the bar consistently. This artificially forces innovation on manufacturers to produce cleaner engines, all with the aim of cleaning up the air that you and I breathe.
As to why they don’t put more effort into forcing innovation in the aviation industry, maritime transportation industry, and military industry, where most equipment has zero or almost zero emissions components, is beyond me. But, that’s not the point of the article.
So, with the 6.0L they were able to squeeze by the emissions standards, but the 6.0L ended up becoming incredibly problematic and cost Ford a ton of money in warranty claims. So, Navistar came back to them with the 6.4L, which was supposed to provide even better emissions output to continue passing the stricter standards and fix the problems created with the 6.0L.
Unfortunately, the 6.4L Powerstroke also was a very problematic engine and Ford only used it from 2008 to 2010. After the failure of both the 6.0L and 6.4L, Ford dropped Navistar and decided to design and build their next Powerstroke engine in-house, which was the 6.7L. That was back in 2011, and the 6.7 is still being used today, which is a testament to how superior it is to the Powerstroke engines before it.
But, although it’s much better than the earlier Powerstroke engines, it isn’t completely problem-free. Real quick I want to mention that there are three generations of the 6.7L Powerstroke: the 1st gen from 2011 to 2014, the 2nd gen from 2015 to 2019, and the 3rd gen from 2020 to now.
Bosch CP4.2 Injection Pump
With that out of the way, let’s start off with arguably the most fatal flaw of the 6.7L Powerstroke, which is the injection pump. This injection pump comes from Bosch, and it’s known as the CP4.2, which is the same injection pump you’ll find on other diesel trucks such as the LML Duramax, some 6.7L Cummins, the 5.0L V8 Cummins in the Titan XD, as well as many other applications.
It’s arguably the most popular injection pump available for manufacturers to use, but it’s also known for being quite problematic. If the pump self-destructs, it will send metal fragments through the lines and rails, into the injectors, and then out the return system. Detecting this failure before it happens is basically impossible, and by the time it’s through, you’ll be need to replace the pump, lines, rails, injectors, and more.
The problems typically occur when contaminants get into the fuel. The whole reason that manufacturers chose the use the CP4 pump over the CP3 pump is production cost and weight. The CP4 pump is much lighter thanks to its aluminum construction and also cheaper. Typically these pumps see failure at or before the 100k mile mark, depending on the quality of the fuel and how well the truck is maintained.
While there isn’t really a singular source of the problems with the CP4 pump, a lot of it revolves around debris and metal shavings from cam erosion. Those metal shavings are eventually passed through the whole fuel system and as time goes on, it’s really only a matter of time until something fails entirely.
There’s not really one way to fix this problem, but there are some aftermarket solutions to help cover it up and sort of fix it. Also properly maintaining your fuel system will almost entirely fix this problem.
The next major issue is one that actually surprised me during the research phase for this article, and that’s the turbocharger.
Most of the turbo issues start with the turbo itself, which is the Garrett GT32 SST. That’s the turbo Ford used on the 2011 to 2014 models. Before we get into the problems on the turbo, I want to quickly highlight what makes this turbo so interesting: and that’s the fact that it’s effectively two turbos packaged in the size of one turbo.
This works by using two compressor wheels while only using one turbine wheel. Unfortunately, this turbo has really small compressor wheels, which means it has to spin very fast in order to produce the target boost levels needed for the amount of performance the engine offers, which is where some of the problems start.
In stock form, it’s not uncommon to see shaft speeds hit over 100,000RPM and over 150,000RPM when tuned. Unfortunately, this meant that 2011 to 2014 Superduty trucks didn’t have exhaust braking ability, because Ford wanted to keep the turbo alive and exhaust braking would definitely kill it even quicker.
With such a high shaft speed, there’s a ton of work for the bearings to do. The GT32 SST generally fails due to the dual ceramic ball-bearing center section that Ford used, but they fixed some of this by switching to steel bearings in 2013. Ultimately though, this turbo didn’t give them the peak performance they wanted, so in 2015, when the Gen 2 motor came out, they switched to a more traditional style turbo with the Garrett GT37.
This new GT37 featured a much larger 61mm compressor and 72.5mm inducer, compared to the GT32 SST with its 46mm compressor and 64mm inducer. By using much larger turbo wheels, this new turbo flows way more air and doesn’t have to work nearly as hard as the old turbo, which simply means lower shaft speed and more power. The GT37 also utilizes a journal bearing center, which is necessarily better, but definitely cheaper to rebuild when it fails.
It’s also worth noting that the 2011 to 2012 trucks commonly have a coolant leak on the turbo coolant inlet pipe, but Ford quickly fixed that issue.
EGT Sensor Failure
The next issue I want to cover is one that caused a lot of controversies because it left emergency vehicles powered by the 6.7L stranded on the road. At least one faulty EGT sensor was identified on 2001 and 2012 model year F-350/F-450/F-550 trucks equipped with the “Ambulance Package”. The emissions after-treatment system on the 6.7L Power Stroke diesel features several EGT sensors. When one of these sensors fails, a vehicle may shut down while driving and/or fail to restart.
Outside of the ambulance packaged trucks, the EGT sensors generally are known for being problematic on the 6.7L Powerstroke, and again, if one sensor fails, you can be left stranded. To be fair though, the sensors are cheap and super easy to replace, so if this happens to your truck it’s really not that bad.
Moving on, the next common issue is something that plagues pretty much all diesel trucks with modern emissions equipment, and that’s the EGR cooler. Luckily, after all the EGR Cooler issues with the 6.0L and 6.4L Powerstroke, Ford worked hard to ensure the 6.7’s EGR cooler system would be much more reliable, but unfortunately, it’s still a source of problems.
Like the 6.4L, the 6.7L utilizes two EGR coolers, but they’re enclosed within a common housing instead of being separated. The common housing is specifically designed to allow for expansion and contraction without rupturing the EGR coolers The EGR valve also controls exhaust flow before the EGR coolers rather than after it like previous Powerstroke engines.
While it doesn’t rupture nearly as often as the older EGR coolers, the 6.7’s EGR cooler is still known for getting clogged with soot, especially on trucks that have a lot of idle time. Because diesel engines don’t produce that much heat while idling, they don’t burn up hydrocarbons, so trucks with tons of idle time well end up with a ton of soot in the EGR cooler that could’ve been burned off if the truck was driven during those hours rather than idling.
Because they moved the EGR calve to the hot side, Ford mostly fixed this issue, but it’s still there. For people who don’t particularly care about having a legal truck, fully deleting this system is the easiest fix and will ensure the problem never comes back, but it’s a pretty big fine if you get caught on the road with a deleted truck, so tread lightly.
Other Minor Issues
The last few problems I wanted to cover are that the nitrogen oxide sensors are known for failing quite a lot on the 2011 to 2012 trucks. Those same early model trucks are also known for having defective radiators from the factory. On top of that, early production engines are known for dropping glow plugs, which can cause catastrophic failure.
I think it’s worth mentioning though, these incidents were not widespread and there have not been enough cases to prompt a recall. It also doesn’t appear to be an issue on later trucks and is almost entirely associated with earlier chassis cab models.
There are also issues with the upper oil pan gasket leaking a ton on 2013 and later trucks because of Ford switching to a silicon style gasket, the crankcase pressure filter clogging up and causing pressure to go through the roof which then creates oil leaks,
Outside of the issues we went over in this article, the 6.7L Powerstroke is a very reliable engine. It’s miles ahead of the 6.0L and 6.4L. Depending on who you ask, some people will say it’s the best Powerstroke engine ever.
I’ll leave that debate to you guys, because the 7.3L is also a very good Powerstroke, mostly because it’s a massive engine with low power output and zero-emissions systems. But, considering the 6.7L is more powerful, cleaner, and pretty reliable, you really could make an argument that it’s the best Powerstroke ever, but again, I’ll let you guys get into that in the comments.
I think it’s also worth mentioning that most of the problems mentioned were on the Gen 1 engines. By the time Gen 2 rolled around, many of the issues were fixed, outside the EGR cooler which will almost always be a problematic part on big diesel engines.