Much attention has been focused on Ford’s 6.7-litre Power Stroke diesel engine with the announcement of the new High Output version. The 6.7-liter engine has endured more than a decade in three generations of Ford Super Duty trucks. It has been a reliable workhorse of power that was designed and produced exclusively by Ford. Now, with the 2023 6.7 HO making 1,200 lb-ft of torque, buyers want to know how good or bad Ford’s six-seven has been.
Nothing is perfect and problems have arisen during the long life of diesel. Some affect only certain generations, while others affect all six or seven generations. We will see the main problems that arise in forums and treatises.
What are the three generations of the 6.7 Power Stroke engine?
The three generations of the six and seven are the Super Duty F-Series trucks from 2011 to 2014, from 2015 to 2019, and from 2020 to 2023. According to our friend KJ at motor trend, the first generation is the one that generally has the most problems. But some of those problems have carried over through all the years of Powerstroke.
Known issues with the first generation diesel resulted in a revised 2015 second generation. Torque and horsepower were increased, but reliability issues were also addressed. The same can be said of the current generation of 6.7 liters. The following are the most common problems that afflict the six-seven.
turbocharger problems
The first generation 6.7 used a rather unique design for its turbocharger. It was actually more like a turbo compound system with two of them in tandem. Once the exhaust gases pass through the first turbo, the compressed exhaust passes through two smaller units to further increase its compression.
So there’s a lot more air volume going through the turbo. Early versions used ceramic wheel bearings, which frequently failed. Steel bearings soon replaced them with much better results. Aftermarket upgrade kits are a smart purchase to get more longevity out of this more complicated turbo setup.
6.7 Exhaust Sensor Faults
There are four exhaust sensors. Unfortunately, when a sensor fails, the truck goes into limp mode. The code displayed will identify which of the four has failed, making diagnosis easier. And replacing them is a fairly simple process.
turbo coolant leaks
Some posters have described coolant collecting on top of the engine. This is caused by a leak in the turbo coolant line connection. Unfortunately, accessing it requires removing the upper intake manifold. But replacing the connection and the refrigerant line usually fixes the leak.
6.7 Obstructions in the EGR system
Although quite robust, the main problem with the EGR system is clogging. Soot is packed into them, which will trigger a code. Although it is fairly easy to replace, you may need to scan your system for other, less common problems. Or you can just replace the cooler and hope that the system works normally.
Glow plug failure
This was a recurring problem with the first year 6.7 liter. When glow plugs fail, they can rupture and cause catastrophic engine damage. Your best bet is to determine if the glow plugs have been upgraded, or replace them if you’re unsure. Replacement glow plugs cost between $30 and $60 each.
Fuel pump/fuel system problems
The 6.7 Power Stroke fuel system will normally give the owner no trouble. That is unless the injection pump fails. If this happens, debris will run throughout the fuel system, which means that not only the injection pump, but also the injectors and pressure regulators must be replaced. In addition, the entire system will need to be cleaned first.
A tip is to regularly replace the filters to prevent particles from impacting the fuel pump. It is also recommended to use a better diesel mix, instead of that old cheap stuff.