Ford introduced its first in-house designed and built diesel engine, the 6.7-liter Power Stroke V8, in 2011. Since then, it has developed a reputation for being a generally solid and reliable platform. When it debuted, the 6.7-liter Power Stroke made a best-in-class 370 hp with 735 lb-ft of torque. Output has grown through the years, with 2025 standard output engines offering 475 hp with 1,050 lb-ft along with a high-output version that makes 500 hp and 1,200 lb-ft.

However, like any new engine platform there were a couple big issues that cropped up early on. From 2011 to 2019 the engines were plagued with Bosch CP4.2 high-pressure injection pump failures. Lack of lubrication in the fuel would cause the pumps to explode, which would send metal shrapnel through the entirety of the fuel system leading to a costly and time-consuming repair. Ford updated the pump to a newer “RP8” unit in 2020 to address the issue.

From 2011 to 2015 Ford utilized a Garrett GT32 single-sequential turbocharger. This turbo, however, proved to have durability issues, particularly with bearing and variable geometry vanes. Soot buildup would lead to sticking vanes and actuator issues. This turbo was replaced in 2015 with a traditional single turbocharger.

Outside of those there have been just a handful of recurring problem areas that owners and technicians have learned to watch for. Thankfully, the aftermarket has worked up solutions for many of these issues. With a little bit of time and effort the 6.7-liter Power Stroke can be easily hardened against these irritating failures.

6.7-liter Power Stroke Issue: Brittle And Cracked Thermostat Housing

While it’s not the most common type of coolant leak, Ford’s 6.7-liter Power Stroke engines have a special knack for developing cracks at the thermostat housing. When the engine debuted in 2011 it came fit with a new plastic thermostat housing. Over time and with repeated exposure to heat cycles, this fitting can become brittle.

Much like a leaky water pump of old, this issue can go unnoticed until it’s too late. Often owners will notice a slight sweet smell of coolant during or after engine operation. This is the first hint that a crack has formed. A low coolant level in the degas bottle or visible wet spots come next. If left unchecked this can ultimately lead to a full loss of coolant and overheating.

Thankfully, Fleece Performance has a solution for this. The company’s replacement thermostat housing is made of cast aluminum and comes with a fresh set of O-rings. The new thermostat housing fits all 6.7-liter Power Stroke engines from 2011 to current, in trucks from F-250 to F-750 Super Duty. The new part takes about an hour to install and requires just an 8mm socket and a flat blade screwdriver. You will need to drain and refill the coolant.

6.7-liter Power Stroke Issue: Cracked Fuel Filter Housing Can Cause Engine Fire

Even a single engine fire is one too many. Unfortunately, this reality has been a topic of conversation among 6.7-liter Power Stroke V8 owners for years. Back in May of 2024 federal regulators with the U.S. Office of Defect Investigations (ODI) began looking into complaints that Ford F-Series Super Duty trucks powered by the 6.7-liter engine may be susceptible to a fuel leak caused by faulty fuel filter housing parts. It’s estimated that a total of nearly 211,000 2015 to 2021 model year trucks may be at risk.

The issue stems from a faulty secondary fuel filter housing. Allevard Sogefi USA, which manufactures the filter housings for Ford, stated the truck’s low-pressure fuel system can run at a maximum pressure of 8.5 Bar (123 psi). However, the secondary filter housing had only been tested to 7 Bar (101.5 psi). A change in the manufacturing process in 2022 means that those trucks, and newer, shouldn’t be affected by this issue.

The NHTSA say it has, so far, received 27 complaints from owners alleging that they have experienced an unexpected fuel leak. Of those, 12 claim that a fire occurred and four of which have led to injuries. And in 2022 Ford recalled about 20,000 trucks to address the issue.

While owners continue to wait on Ford to provide a fix (or even fully acknowledge the issue), Fleece Performance has developed its own solution. The company’s billet aluminum fuel filter cap and fittings eliminate the risk of cracking all together. This assembly locks directly into the factory location and utilizes a replaceable spin-on Donaldson filter that is easy to service. They even throw in a second replacement filter.

The installation is incredibly easy, taking just 15 minutes to complete. The kit also comes with a CARB E.O. number for trucks that require emissions testing in California.

6.7-liter Power Stroke Issue: Leaking Injector Return Fitting

While the 6.7-liter Power Stroke’s fuel filter housing has received much of the attention for its crack and leak, the injector return fitting that attached to the housing isn’t without its own faults. Repeated disconnects for fuel filter changes coupled with under hood heat make this fitting just as susceptible to failure.

Fleece Performance makes a heavy-duty replacement fitting that is crafted from billet aluminum, features a dual O-ring internal design, and is serviceable. The new fitting is designed to work with both the factory fuel filter housing and aftermarket solutions such as Fleece’s own billet replacement. Fleece offers two different part numbers, one for 2011 to 2016 trucks and the other for 2017 to current. Installation takes just a few minutes and is as simple as cutting off the old fitting and slipping in the new one.

6.7-liter Power Stroke Issue: Subpar Fuel Filtration

Did you know, 2011 to 2025 Ford F-Series Super Duty trucks actually have to sets of fuel filters? That’s right, they do. While the under-hood filter housing gets most of the attention (for obvious reasons) the primary filter also leaves plenty of room for improvement. Fleece offers what is a true “drop-in” upgrade to the factory “furnace” style filtration system. The new unit mounts in the same location as the factory filter housing and mates directly to all factory fuel lines. It also retains full functionality of the Water-In-Fuel (WIF) circuitry and chassis harness connectivity. A spin-on Donaldson filter offers improved efficiency (99-percent) at low micron levels (4 micron) while still ensuring peak water separation performance.

For those in a colder climate Fleece also offers an optional fuel heater for all models that easily installs into the side of the filter base for full fuel flow heating prior to the filter. Worried this work with your extended range aftermarket tank? Never fear, Fleece says it will indeed fit with both Titan and S&B fuel tanks. Installation takes about 30 minutes and requires only basic hand tools. A CARB E.O. number is provided for California trucks. And for those with a 2011 to 2016 Super Duty, the company’s PowerFlow Lift Pump (or SureFlow sending unit for those running an external fuel pump) make the perfect addition to the rounding out a robust fuel system.

Issue: Illuminated Charging Circuit Dash Light

While this may seem like an odd problem to most, it’s one that owners of 2011 to 2016 6.7-liter Power Stroke Super Duty trucks are all too familiar. Due to the routing, exposure, and general lack of protection for the small charging circuit sense wires that are routed from the Powertrain Control Module (PCM) to the alternator it is common for the wire to become damaged. The OE harness runs through a plastic channel that is located on the underside of the engine as well as exposed in sections between the channels. These locations are subject to vibration along with harsh environmental exposure. If these wires become damaged, stressed, or chaffed the PCM reads it as a charging system fault and illuminates a malfunction indicator lamp (MIL) on the dash. While some owners opt to just live with the light, Fleece Performance offers a solution to fix this once and for all.

The company’s charging circuit harness for 2011 to 2016 trucks is a drop-in replacement that requires no cutting or splicing. The harness is designed and produced in-house on a fully automated wire cutting and terminal crimping machine. This ensures that every piece is the highest quality. Installation takes about 30 minutes and requires only a 10mm socket and some patience.

In addition, the company also offers replacements for several other commonly failed electrical connectors including the heated seat module pigtail, lift pump pigtail, water-in-fuel sensor pigtail, cooling fan adapter harness, and more.

Final Thoughts

The 6.7-liter Power Stroke diesel engine is widely considered the most reliable diesel that Ford has ever offered, especially when compared to its 6.0 and 6.4-liter predecessors. And it has demonstrated this through 15 years of faithful service. Owners are now reporting engines achieving 250,000 to 350,000 miles, with some fleet owners pushing half a million miles on their 6.7-liter-powered trucks. And, with a little help from aftermarket parts such as these, we expect to see these engines soldier on for decades to come.