6.7L Power Stroke Common Problems
Picture this: You are searching through the lot of your favorite Ford dealer shopping for a new or used diesel truck when you spot a newer Super Duty truck. Your eyes widen and your heart paces because you can't wait to get behind the wheel of a quiet purring 800.ft.lb producing monster known as the 6.7L PowerStroke. However, you can't help but wonder if the reliability issues of the previous generation will haunt you.
International engines are generally reliable power plants that were the driving force behind Ford trucks for many years. That being said, I believe Ford's decision to produce their own diesel engine was a grand move to finish the divorce between Ford and International. Ford needed to step away from International to re-establish reliability in the Super Duty brand. The design changes for the 6.7L are also a huge part of it's success as well as making it harder to work on.
One of the largest changes was the reverse flow cylinder heads. This puts the exhaust manifolds and the turbo securely in the center of the engine above the valley and places the intake ports on the outside of the cylinder head. The intake runners that attach to the upper intake are engineered to be a part of the valve cover assembly.
They also feature advanced glow plugs, additional glow plug control, and injectors that can fire up to 5 times during a single stroke. The much less impressive (to normal people) additions to the engine include a SCR catalyst system with diesel exhaust fluid, hot side EGR valve, additional NOX system sensors, additional exhaust system temperature sensors, and a complete secondary cooling system.
Luckily, these engines have been fairly reliable. I have put together a 6.7L Power Stroke common problems list. We do not see a large percentage of engines with serious issues, but they do have a few of these common problems that have become pattern fixes outlined below.
6.7L Power Stroke Oil Leaks
On all generations of the 6.7L Power Stroke the upper oil pan gasket leaks that require the removal of the transmission for in chassis repair. Depending on the year, some have a molded gasket or RTV. 2nd Gen 6.7L Powerstrokes are experiencing failure of the PCV seperator assembly causing excessive crankcase pressure which leads to excessive oil leaks. This failure often goes unnoticed! Failure to replace the PCV separator assembly could result in reappearance of the oil leaks. It's easy to check if you have an issue - just remove the oil filler cap with the engine running and listen for similar results as this video - 6.7L Power Stroke Excessive Crankcase Pressure.
First generation 6.7L Power Stroke leak from the vacuum pump gasket. I wrote about my personal encounter with my first one under the Tech Tales blog - Oil Leak Front Cover on 6.7L Powerstroke. This issue could have been easily rectified with the addition of lock-tite or a higher torque spec at the factory. The bolts are almost always loose. Tightening the bolts fixes the oil leak but it is recommended to replace the gasket. To repair the oil leak, you must remove the fan shroud cover, the belt, and cooling fan assembly.
6.7L Power Stroke EGT Failure
The most common cause of check engine lights and stop safely warnings are the Exhaust Gas Temperature sensor failures. So frequent that Ford has issued a warranty extension under a FSA action to cover these sensors. That's good news for consumers - at the dealer we change a few every week. Most of the time these sensors are easily replaced, with some requiring heating the bungle with the aid of the torch, and possibly using a machinist tap to repair the threads. You could always check out the guide on Changing 6.7L Power Stroke EGT Sensors.
6.7L Power Stroke EGR Cooler
Another hot issue is the new EGR design because the valve has been relocated from the cold side to the hot side. The 6.4L and 6.0L EGR systems flowed from the exhaust, through the coolers, then to the valve. The new 6.7L PSD design has the EGR flow from the hot exhaust, to the valve, then through the coolers. This design reduced the carbon deposits forming on the EGR valve that caused problems on the 6.0L / 6.4L but the new design allows the soot deposits to occur in the EGR cooler core.
The EGR cooler core can become completely clogged with carbon deposits in severe cases, even on low mileage vehicles. If you have DTC P0401 stored in your PCM, the 6.7L Power Stroke EGR cooler replacement is likely how to fix your problem.
Keep reading to next page to find out more common problems with the 6.7L Power Stroke engine.
6.7L Power Stroke Coolant Leaks
Depending on the year, you could have experienced multiple leaks from the radiator, turbo coolant inlet fitting, and water pump. The turbo coolant inlet fitting design on the pre-2017 is the most common leak and easy to replace with the removal of the upper intake. The second most common leak tends to be radiator leak. Primary Radiator replacement is somewhat labor intensive because of the size, angle of mounting, and the addition of the secondary cooling system. The third most common coolant leak fix is 6.7L Power Stroke Water Pump Replacement. Slightly in-depth but manageable job if you can handle intermediate mechanical work. Other areas to keep a lookout for is the oil cooler T-line located on the drivers side near the front of the oil pan, as well as a radiator hose o-ring leakage.
6.7L Power Stroke Turbocharger Failure
There have been numerous turbochargers being replaced due to bearing failure, mostly on earlier generation. Turbocharger failure is a direct result of Ford using smaller than adequate turbocharger to produce massive amounts of boost and air flow required on this engine application. Turbocharger over-speed is cause of failure and intensified by aftermarket performance enhancements. Chipped or tuned engines can experience this problem. Ford was already pushing that turbo to it's limit. Your problems can be solved with aftermarket performance turbocharger assemblies on earlier models. A few changes in the turbocharge size happened based on years but 2nd generation of engines (models 2017+) and above are now using a larger turbocharger to reduce failures (and create more power!). The compressor wheel size difference is astonishing between early 6.7L and the newer ones in the aluminum body trucks.
6.7L Power Stroke SCR DEF Injection
No surprise here; several components have been repeat offenders. One of the most common DEF system failures is the heating element inside the DEF sending unit causing a P20BA Reductant Heater A Performance. The only way to fix that is replacement of the DEF sending unit assembly. For those that don't know, P20BE Reductant Heater B Performance is not as common, but it is referencing the heated line that carries the DEF from the pump to the injector. Few 2011-2012 models actually have a customer satisfaction program (recall) extending the warranty so that replacing the sender assembly for heater failure is at no-cost. A P207F is a conditional code that can sometimes be set for multiple reasons from a weak DEF pump, contaminated DEF fluid, or from weak / watered down DEF and causes Forced Limited Idle and Engine Speed Limited to 50MPH. I've written a guide to P207F Diagnostic Tips.
6.7L Power Stroke Glow Plug Failure
Something that has come up in the past was glow plug failures. It was pretty specific to the 2011 model year. The tips would come off the glow plug and cause catastrophic damage. The plugs were revised in future engines but I don't know the build date. Most other failures of the newer engines 2012+ were usually from something else failing like an exhaust valve and the glow plug tip would become damaged during the process. I would say simple common sense should take over - just make your glow plugs a maintenance item and change them at 100K mile intervals. Why not be safer than sorry, especially once out of warranty. It's a pretty easy job to do.
Here are a few less common issues but we have seen: fuel rail pressure sensor failures, fuel rail temperature sensor failures, broken injector return lines, NOx senors (now under a TSB), and other repairs that require the replacement of the entire SCR system. High pressure fuel system contamination is a very common, very expensive repair but happens most frequently from customer error from water contaminated fuel or DEF additions to the fuel tank.
Some technical service bulletins, TSB's, for the above mentioned problems can be found at 6.7L Power Stroke TSB Reference.
Something to be aware of is that the new 6.7L Power Stroke getting released in the 2017 line of Super Duty's has a few significant changes to the PCM, turbo, and other emissions strategies. This revised engine line will be dubbed Gen2 and fixes several well know problems. The new diesel class will eliminates training for the 6.0L PSD and the 6.4L PSD as most, if not all, have surpassed even extended warranties except in cases of remanufactured engine installations..
My review of the 6.7L Power Stroke is that this is one of the best diesel engines on the market. It easily out-powers and is more reliable than any other Power Stroke engine of the past. Don't be afraid to buy one and drive it till the wheels fall off.