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 the 6.7L Powerstroke engine.
I have to say that International engines are generally reliable power plants that have been the driving force behind Ford trucks and other makes 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 a bit 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 Powerstroke common problems list. 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.
6.7L Powerstroke Oil Leaks
I recently moved this to the top of the list because this seems to be very common now. On all generations of the 6.7L Powerstroke, (more common on second generation) the upper oil pan gasket leaks. This seal is simply RTV but it requires the removal of the transmission to repair if done in chassis. It appears a high amount of trucks are experiencing failure of the PCV seperator assembly causing excessive crankcase pressure which leads to excessive oil leaks. This failure often goes unnoticed! Replacement of the PCV seperator would be required. Failure to replace the PCV seperator assembly could result in addition 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 quick small video - 6.7L Powerstroke Excessive Crankcase Pressure.
First generation 6.7L Powerstroke tend to 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. Seems like this is issue that could have been easily rectified with the addition of lock-tite or maybe a higher torque spec on the bolts from the factory as the bolts are almost always loose. Most of the time, simply tightening the bolts causes the leak to stop but it is recommended to replace the gasket. The leak often looks as if its leaking from the front main seal. To repair the oil leak, you must remove the fan shroud cover, the belt, and cooling fan.
6.7L Powerstroke EGT Failure
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. You could always check out the guide on Changing 6.7L Powerstroke EGT Sensors.
6.7L Powerstroke 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 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 but there are always drawbacks to design changes: 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 lower mile vehicles. If you have DTC P0401 stored in your PCM, the 6.7L Powerstroke EGR cooler replacement is likely how to fix your problems and a relatively simple, straight forward process.
Keep reading to next page to find out more common problems with the 6.7L Powerstroke engine.