How to Bulletproof a 6.7 Power Stroke (2015–2019): What Fails and How We Fix It
What does bulletproofing mean?
Bulletproofing is a term that came out of the early diesel enthusiast community. It means fixing an engine's known weak points before they fail — replacing the factory parts that tend to break with better-designed ones. No engine is truly bulletproof; it means the failures that engine is known for have been dealt with.
Why do it before something breaks?
A failure rarely takes out just one part. One weak part failing often damages the parts around it. Fixing the first link costs far less than the chain.
You choose when the truck is down — not the side of the road with a trailer behind you.
Doing the work together saves labor. When parts are already off for one job, the next one costs less to do at the same time.
Documented work helps resale. Buyers who know these engines ask whether it's been done, and receipts answer that.
What bulletproofing isn't
Removing emissions equipment. Deletes are illegal on road vehicles under current federal law, so Westco doesn't do them. If that law changes, we'll revisit it.
On a 2015–2019 6.7 Power Stroke, the things that matter most are the upper oil pan seal (an RTV silicone bead that commonly starts leaking between the pan and the block), protecting the fuel system from a CP4.2 high-pressure pump failure, and keeping the EGR, DPF and DEF systems healthy instead of letting them clog. These trucks got a new turbo for 2015, so the early 6.7's turbo bearing failures are mostly behind them. Call Westco at (719) 591-7743.
Free Diesel Health Report ($220 value) with code PS6715. Details at the end of this article.
Which 6.7 Power Stroke years and trucks does this cover?
This covers the second-generation 6.7L Power Stroke V8 in 2015–2019 Ford Super Duty trucks: F-250, F-350 and F-450 pickups, the F-350 through F-550 chassis cabs, and the F-650/F-750 medium-duty trucks that got the 6.7L in this era.
For 2015, Ford replaced the GT32 turbo with a larger GT37, put in a revised high-pressure fuel pump and injectors, and raised the pickup rating to 440 hp and 860 lb-ft. The 2017 Super Duty was a new truck with an aluminum-alloy body, and torque went to 925 lb-ft. The 2020 engine changed a lot inside, so it isn't covered here.
Shopping across years? Our Power Stroke buyer's guide covers the whole family.
Why does the upper oil pan leak on a 6.7 Power Stroke?
The pan itself is usually not the problem — the RTV is. On these trucks, the aluminum upper oil pan is sealed to the bottom of the block with a bead of RTV silicone instead of a gasket, and that bead commonly lets go and starts weeping oil.
The part: The aluminum upper oil pan, bolted to the bottom of the block, with the lower pan bolted under it.
What physically fails: RTV only seals as long as it stays bonded to both metal faces. If any oil film or old silicone was left on the surface when it was assembled, the bead never bonds fully and oil finds its way past. Age and heat cycles work on it too. And if the crankcase ventilation (CCV) filter clogs, pressure builds inside the engine and pushes oil out through the weakest seal — very often this one. Ford's own leak guidance for these years names a clogged crankcase vent oil separator and/or a sealing concern as the causes.
What Ford changed: Early 6.7s used a press-in-place seal on the upper pan. Around the start of this generation, Ford went to RTV only. Ford's repair bulletin for this leak, TSB 22-2201, covers 2017–2019 Super Duty and F-650/F-750 trucks. It's still an RTV reseal, and it says plainly that cleaning and prepping the sealing surface is "absolutely critical." It bans metal scrapers, wire brushes and rotary tools on the sealing face, and calls for a surface-prep step to make sure no oil film is left. A gouged sealing face or a surface that still has oil on it is a setup for a repeat leak.
Ford's leak-diagnosis guidance also covers 2015–2016 trucks.
How we fix it: Westco first confirms the source, since an oil filter, oil cooler, CCV or rear main leak can run down and look like an upper pan leak. On an RTV-sealed truck, our preferred repair is converting to a gasketed upper pan seal, where a molded rubber seal held in a carrier replaces the bead. When we have to use RTV, we follow the full surface-prep procedure.
We also replace the CCV filter and check crankcase pressure on the same job, because too much pressure can blow out a new seal too.
This is a big job. On these trucks the upper pan is very hard to reach in place, so the repair usually means lifting the cab or pulling the engine. That's why it pays to do it once, and fix any nearby leaks while it's open.
Why does the CP4.2 fuel pump fail on a 6.7 Power Stroke?
The CP4.2 high-pressure fuel pump can fail on any 2011–2019 6.7, and when it does it can send metal through the whole fuel system. The 2015 pump was revised, but it's the same basic design.
The part: The engine-driven high-pressure pump that feeds the fuel rails and injectors.
What physically fails: Inside, a camshaft drives plungers through roller tappets, and diesel fuel is the only thing lubricating them. If air gets into the fuel, a tappet can rotate in its bore. The roller then rides across the cam lobe at the wrong angle instead of rolling with it. The fuel film breaks down, metal rubs on metal, and the pump starts shedding debris. Water in the fuel hurts lubrication the same way. Those metal particles go into the high-pressure lines, the rails, the injectors and the return side, so one failed pump commonly turns into a whole fuel system replacement.
What Ford changed: For 2015, Ford put in a revised pump with a longer stroke. It's still a CP4-series pump with the same roller-tappet design, and lawsuits over CP4 failures name 6.7L trucks from 2011 on.
How we fix it: Prevention is mostly about keeping air and water out of the pump and catching debris before it spreads:
Fuel filters changed on schedule with quality filters, and the water separator drained.
Don't make a habit of running the tank close to empty. A low tank on a steep grade can let the system pull air.
A fuel system protection kit that sends the pump's return fuel through an extra filter, so debris is more likely to be caught before it spreads.
A pump conversion: Westco replaces the CP4.2 with a pump that doesn't use the roller-tappet design, wherever conversion parts exist for your truck. Whether it makes sense depends on how the truck is used, and we'll talk through it with you.
We cover this pump family in more detail in our CP4 and 6.0 bulletproofing article.
Does the 2015–2019 6.7 still have turbo problems?
Mostly no. The 2011–2014 GT32 was a dual-compressor turbo with ceramic ball bearings that spun very fast and often failed from overspeeding. The 2015-on GT37 has a single larger compressor wheel and a bigger turbine, spins slower, and runs on a journal-bearing center section. Any turbo still wears, so we check shaft play, oil in the intake and boost codes on high-mileage trucks — but it isn't the known weak point it was.
Why does the EGR cooler clog on a 6.7 Power Stroke?
The 6.7's EGR cooler holds up much better than the 6.0's or 6.4's, but it can still plug up with soot, especially on trucks that idle a lot.
The part: The cooler that chills exhaust gas before it goes back into the intake.
What physically fails: A diesel idling or running light doesn't make enough heat to burn soot off. That soot coats the cooler passages and the EGR valve, which cuts flow and causes EGR faults and poor running. The 6.7 uses coolers in a common housing designed to expand and contract with heat, so cooler ruptures are less common than on the 6.0 and 6.4.
What Ford changed: For 2015, Ford rerouted coolant through the EGR cooler and added a temperature sensor at the cooler inlet on pickups.
How we fix it: Westco cleans or replaces the EGR valve and cooler as needed — a plugged cooler usually means replacement — and finds out why it clogged, such as a bad injector or a truck that idles all day. We never block off or delete the EGR.
Why do DEF, NOx sensor and DPF faults show up on a 6.7 Power Stroke?
These trucks rely on DEF (SCR), a diesel particulate filter (DPF) and several sensors. When one fails, the truck commonly sets a check engine light and can go into reduced power.
The parts: The DEF tank, heater, pump and doser; the NOx sensors and their control modules; and the DPF with its sensors.
What physically fails: DEF systems commonly have heater, pump and level-reading faults. NOx sensors and their wiring can fail — Ford issued service guidance on 2017 trucks for water getting into the NOx sensor module wiring and connector. A DPF that never gets hot enough to burn off soot fills up, regens more and more often, and eventually needs cleaning or replacement.
What Ford changed: Ford issued service bulletins on DEF gauge readings, NOx sensor circuits and DPF pressure sensors in this generation, mostly software updates or single-part fixes.
How we fix it: Westco diagnoses the actual fault, repairs or replaces the failed part, and does any module programming in-house. We'll clean or replace a loaded DPF and look for what's causing the extra soot. Repair only — never delete.
In Colorado Springs, cold mornings make the DEF heater work, and short trips around town don't give the DPF time to regen. A regular highway drive helps.
What should you check before buying a used 6.7 Power Stroke (2015–2019)?
Under the truck:
Oil wetness along the joint between the upper oil pan and the block, especially at the back corners and along the sides. Fresh degreaser in that spot is a question to ask about.
Wetness at the oil filter housing, oil cooler and CCV.
Coolant leaks at the radiator, hoses and degas bottle.
Exhaust system all there. A missing DPF or SCR, or a straight pipe, means a deleted truck. That can fail inspection and cause registration and resale problems.
On the test drive:
Cold start: it should fire quickly and settle down without a lot of smoke.
Pull a grade under load. Monument Hill or Ute Pass will tell you a lot. Watch for hesitation, a loss of power, or a reduced-power message.
No surging or stumbling that could point to a fuel delivery problem.
With a scan tool:
Stored and pending codes, including fuel rail pressure, EGR, NOx, DEF and DPF codes.
Fuel rail pressure, actual versus desired, under load.
DPF soot load and how often it's regenerating.
Signs the engine has been tuned.
Westco's used diesel pre-purchase inspection covers all of this.
What in the service records shows it's already been done?
An upper oil pan reseal or gasket conversion, ideally saying which method was used and that the CCV filter was replaced at the same time.
Fuel filter changes on schedule, plus any fuel system protection kit or high-pressure pump replacement, with the reason it was done.
EGR valve or cooler service, and DPF cleaning or replacement.
DEF heater, pump or NOx sensor replacements, and PCM software updates for emissions bulletins.
If the truck is covered by an extended warranty, claim paperwork. Westco works with all extended warranty companies and can help with extended warranty claims.
Get a free Diesel Health Report on your 6.7 (code PS6715)
We'd like to be your diesel shop. Here's how we'd like to earn it.
Mention code PS6715 and get a complete Diesel Health Report on your 6.7, a $220 value, free. We give it a bumper-to-bumper visual inspection, pull the live data that matters on this engine, run the full set of key-on engine-off and key-on engine-running tests, and photograph what we find. You get a detailed digital report to keep, so you know exactly where your truck stands today.
This is a paid inspection, and our technician is paid to do it right. With your code, it's free to you. No repair to buy, no catch.
Why give it away? Because we'd rather show you how we work than tell you. Our mission is to apply all of our knowledge, skills and experience to take care of your truck, and to have you leave feeling you were treated fairly and professionally. Most of all, we want you to enjoy doing business with the WESTCO family. If the report earns your trust, we hope you'll make us your shop.
What your Diesel Health Report checks on a 6.7
Low-side fuel pressure. Ford's own figures put normal supply pressure around 4.5 bar (about 65 psi), and the high-pressure pump needs at least about 3.5 to 3.7 bar (about 51 to 54 psi). Below that, the truck shows a low fuel pressure message and sets a code. Readings near the low end are worth a closer look at the filters and supply side.
Fuel rail pressure, desired vs. actual. We compare what the computer asks for with what the CP4.2 delivers. A gap between them is worth a closer look.
Upper oil pan and crankcase vent. We look for oil weeping at the pan-to-block joint and check the crankcase vent (CCV) system, since crankcase pressure is what pushes oil past that seal.
DPF soot load and regen history, plus DEF and NOx data. We check how often it's regenerating and that the emissions sensors are reading correctly.
Visual. Coolant level and lines, the degas bottle, and leaks bumper to bumper.
Normal readings vary by year, calibration and scan tool. Your report shows where your truck sits and what's worth watching.
Health report or diagnostic?
The Diesel Health Report is a checkup for a truck that's running fine. If yours is running rough, smoking, down on power or showing a code, it needs a diagnostic instead. Call us and we'll get it in.
How to redeem it
Call (719) 591-7743 and mention code PS6715, or
Book online and type PS6715 in the "What does your vehicle need?" box.
New and returning customers, one per truck. Good through January 31, 2027.
Other Power Stroke generations
Bring it to Westco
Westco does this work in-house: upper oil pan reseals and conversions, fuel system work, EGR and emissions repair, and factory-level programming. Our ASE-certified techs back the work with a 24-month/24,000-mile parts and labor warranty. Learn more about our Power Stroke service.
Book my FREE Inspection or call (719) 591-7743.
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