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. Read more to get an idea of the common problems with this engine.
I have to say that International engines are generally very reliable power plants that have been the driving force behind Ford trucks, and many other makes, for many years. That being said, I believe Ford's decision to produce their own diesel engine was an ingenious one. Ford needed to step away from International a bit to reestablish 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. This isn't quite a 6.7L Powerstroke Review, but a list of common problems. We do not see a large percentage of engines with serious issues, but they do have a few common problems that are starting to be pattern fixes that I have outlined below.
Exhaust Gas Temperature sensor:
The most common cause of check engine lights and stop safely warnings are the Exhaust Gas Temperature sensor failures. They are 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 others using a machinist tap to repair the threads. Either way it's a relatively simple fix for most technicians. You could always check out the guide on Changing 6.7L Powerstroke EGT Sensors.
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 Powerstroke design has the EGR flow from the hot exhaust, to the valve, then if the valve is open through the coolers. It effectively reduced the carbon deposits forming on the EGR valve that caused many problems on the 6.0L / 6.4L. There is always drawbacks: the new design allows the deposits to occur in the EGR cooler core. The EGR cooler core can become completely clogged with carbon deposits in severe cases. If you have DTC P0401 stored in your PCM, the 6.7L Powerstroke EGR cooler replacement is likely how to fix your problems and is a relatively simple, straight forward process.
These years have experienced high percentages of radiator, turbo base coolant seal, turbo coolant inlet fitting, and water pump leaks. The turbo coolant inlet fitting is the most common and is rather easy to replace with the removal of the upper intake, but removal of the turbo charger for replacement of that block to turbo gasket is a much harder task. The radiator replacement is actually one of the most labor intensive radiators I have ever changed because of the size, angle of mounting, and the addition of the secondary cooling system radiator. The second most common coolant leak fix on the 6.7L Powerstroke is water pump replacement. It is slightly in-depth but manageable if you can handle intermediate technical work.
I have come across a few oil leaks coming from the front cover area because of the loosening of the vacuum pump bolts. I wrote about my personal encounter with my first one under the Tech Tales blog - Oil Leak Front Cover on 6.7L PowerStroke. Seems like this is issue that could have been easily rectified with the addition of locktite or maybe a higher torque spec on the bolts from the factory. Most of the time, simply tightening the bolts causes the leak to stop. The leak often looks as if its leaking from the front main seal. To change, you must remove all the stuff from the front accessory drive which would include removing the fan and cover assembly.
There have been numerous turbochargers being replaced due to bearing failure. 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 likely the main problem and usually is intensified by aftermarket performance enhancements. Chipped or tuned engines can experience this problem sooner. Ford is 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 has happened, but 2nd generation of engines (models 2017+) and above are now using a larger turbocharger to reduce failures (and create more power!).
SCR and 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. A P207F can sometimes be set for multiple reasons from a weak DEF pump, contaminated DEF fluid, or from weak / watered down DEF.
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 Powerstroke TSB Reference.
Something to be aware of is that the new 6.7L PowerStroke 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. Ford has talked about decertifying all current diesel technicians and forcing them to take a revised diesel class. The new diesel class will eliminates training for the 6.0L PowerStroke and the 6.4L PowerStroke as most, if not all, have surpassed even extended warranties except in cases of remanufactured engine installations..
My review of the 6.7L Powerstroke is that this is one of the best diesel engines on the market. It easily out-powers and is more reliable than any other Powerstroke engine of the past. Don't be afraid to buy one and drive it till the wheels fall off. For those interested in even more power (cue Tim Tool Man Taylor noises), you can pickup one of the BEST chips on the marketplace: Spartan Phalanx II.