6.7L Powerstroke Coolant Leaks
Depending on the years, you could have experienced radiator, turbo base coolant seal, turbo coolant inlet fitting, and water pump leaks. The turbo coolant inlet fitting design on the pre-2017 is the most common leak and is rather easy to replace with the removal of the upper intake. If the turbo base-plate is leaking, removal of the turbo charger would be required The radiator replacement is somewhat labor intensive 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. 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 simple radiator hose o-ring failure. I've written a guide to 6.7L PowerStroke Water Pump Replacement.
6.7L Powerstroke 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 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!). The size difference is astonishing between early 6.7L and the newer ones in the aluminum body trucks.
6.7L Powerstroke 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. 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. 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.
6.7L Powerstroke 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 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.