2017-2019 6.7L Powerstroke Filter Guide (FD4625 / FL2051S / FA1927)

The $18 Filter That Sends Metal Through a $12,000 Fuel System

I have a friend who bought a used 2018 F-250 with 94,000 miles on it. Clean truck, one owner, all the paperwork. First thing he did was the sensible thing: oil change, fuel filter change, air filter change, all in one Saturday.

He bought the fuel filter off a marketplace listing that said “FD4625” on it and cost $18. It threaded in. It sealed. The truck started. Six months later it was cranking for eight seconds before it fired, and a shop pulled the primary filter housing to find the water-separation layer was simply not there — the element was a single wrap of paper in a plastic cage. Water had been walking into the Bosch CP4.2 high-pressure pump the entire time.

That pump runs at roughly 30,000 psi. It does not wear out gracefully. Once water scuffs the internal rollers, the pump sheds metal, and that metal goes through both rails and all eight injectors. The repair is $10,000 to $14,000. He spent $18 to save $40.

This guide exists so that does not happen to you. It covers the 2017-2019 6.7L Powerstroke three-filter service — fuel, oil, and air — what each filter actually does, what the part numbers really mean, what every channel charges in September 2026, and how to install all three without introducing air into the fuel system.

Why the Fuel Filter Is Two Filters, Not One

Most trucks have a fuel filter. The 6.7L Powerstroke has a fuel system.

The primary filter is a fuel/water separator mounted on the driver-side frame rail, behind the front wheel. Its job is to catch free water and the coarse sediment that settles out of the tank before either reaches the pump. The secondary filter is a cartridge element in the engine bay that does the fine filtration — the 4-micron work that catches the particles small enough to score a pump that clearances are measured in microns.

They are replaced at the same time. They are sold together. And the phrase “replace your fuel filter” on this truck means replacing both elements, which is exactly the detail the budget listings leave out. When a listing shows a single can and a single price, you are being sold half a service.

That is why a real 2017-2019 fuel service is a two-stage job with two part numbers that both come under the FD4625 umbrella: the frame-rail element and the engine-bay element. A genuine kit has both. A genuine kit also ships the fresh O-rings, because the housing seals are one-time-use and a reused seal is the number one cause of a post-service fuel leak — and a fuel leak on the suction side is an air leak, which is the other way to kill a CP4.2.

What You Actually Get

The 2017-2019 6.7L three-filter kit covers the three filters most owners service together:

FD4625 — dual-stage fuel filter set. Two elements: the frame-rail water separator and the engine-bay fine filter. Rated for water separation and 4-micron filtration on the secondary stage. Cross-references: FD4624 (the earlier number Motorcraft superseded), HC3Z-9N184-B, HC3Z-9N184-C.

FL2051S — oil filter. A spin-on canister that threads onto the engine and is reached from underneath, next to the oil pan. It filters the 13 quarts of oil through pleated media with a bypass valve so the engine always gets oil even if the media loads up. Cross-references: FL2124S, BC3Z-6731-B, PF67, B7379, P502503, PH10890, LF17494, BC3Q-6714-CA, 57151.

FA1927 — engine air filter. The large element in the airbox with its distinctive outer foam pre-filter. That pre-filter is the giveaway on this generation: it traps the heavy dust before the pleated media sees it, which is what keeps intake restriction low while still protecting the VGT turbocharger. Cross-references: FA-1927, HC3Z-9601-A, PA8219, HC349601AF.

Three filters, three jobs, one box. The cabin filter — the FP92 — is the fourth slot this kit deliberately does not include, because most owners service it on a completely different schedule. If you want all four, that kit exists too.

What You Actually Pay: Ford, Doc’s, Amazon and eBay

I pulled live pricing across every channel in September 2026. Here is the honest landscape for the 2017-2019 three-filter service.

Read the table honestly and two things jump out.

First, against genuine Motorcraft this kit is cheaper. Ford’s own filters, bought one at a time online, run about $124 for the three — and around $126 at the dealer counter before tax. The kit is $111.60, so you are saving roughly $12 to $14 versus buying the exact same grade of part, and you are not making three separate purchases from three separate listings. Against the eBay OEM kit at $192.74 for the same three filters, the gap is more than $80. And if you have priced these over a Ford counter, you already know the feeling: one owner in the video this guide was checked against paid $68 for the air filter element alone — one part, over the counter, in person.

Second, against white-label this kit costs more, and that is the point. An Amazon no-name three-filter kit runs $60 to $70 — roughly $42 to $52 less. Those kits often do not publish a micron rating on the fuel element, they often skip the coalescing media that does the water separation, and a fuel element without that layer is not the same product at all. A $37.99 fuel-and-oil pair is worse than that: it is a single fuel element wearing a two-stage part number, which means you quietly deleted the water-separation stage the whole system exists to provide.

You are not paying for a printed number. You are paying for two fuel elements instead of one, for media with a published rating, for the fresh O-rings, and for one order that arrives correct.

What to Look For When Buying

Count Dual Fuel Elements (FD4625 Set). A complete fuel service for 2017–2019 6.7L Powerstroke trucks requires BOTH the frame-rail water separator and the engine-bay fine element. Beware of partial listings shipping only one element.

Verify Hydrophobic Water-Separation Spec. The frame-rail filter must feature a hydrophobic coalescing layer to trap free water before it hits the 30,000 PSI Bosch CP4.2 high-pressure pump.

Fresh Housing O-Rings Included. Both fuel cartridges run one-time-use rubber seals. Reusing old heat-cycled O-rings causes air leaks on the suction side, accelerating CP4.2 pump cavitation.

Year Cutoff & Part Number Verification. 2017–2019 trucks use FD4625 for fuel and FA1927 for air. 2011–2016 trucks use FD4615, and 2020+ trucks switch to FA2031. They are non-interchangeable.

Genuine Steel Canister Engine Oil Filter (FL2051S). The oil filter must feature a heavy-gauge steel shell with a pre-seated gasket and calibrated internal bypass valve to handle 13 quarts of high-shear diesel oil.

Installation: Three Filters, Three Locations

None of the three is hard. The trick is the order and the priming, so you are not fighting your own work or pushing air through the pump.

Step 1 — Chassis Fuel/Water Separator Replacement (FD4625 Lower Element). 

1. Locate the primary separator on the driver-side frame rail behind the front wheel.
2. Unplug the Water-In-Fuel (WIF) sensor connector before unscrewing housing.
3. Open yellow quarter-turn drain valve to discharge accumulated water and fuel into a catch pan.
4. Unscrew Housing: Use a 32mm socket on hex-cap housings, or remove the 5 perimeter 8mm bolts on bolt-on housings.
5. Swap element, install fresh housing O-ring, and hand-thread back on. (Torque 8mm bolts in a star pattern to 7 ft-lbs / 84 in-lbs; hand-snug 32mm hex caps). Reconnect WIF plug.

Step 2 — Engine-Bay Secondary Fuel Filter Replacement (FD4625 Upper Element). 

1. Locate upper filter under the hood on driver side. Unclip the 3 quick-connect fuel lines (white, blue, red).
2. Rotate cap counterclockwise to release old filter assembly.
3. Install fresh secondary element, rotate clockwise until locked, and reattach quick-connect lines until they CLICK firmly.

Step 3 — Engine Oil & Filter Replacement (FL2051S). 

1. Drain 13 quarts of oil using a 16mm socket on the oil pan plug.
2. Spin off old FL2051S filter. Inspect engine pad to confirm old rubber gasket didn't stick to block.
3. Pre-fill new FL2051S filter ~3/4 full with fresh oil, lube gasket, spin on hand-tight until contact, then tighten an additional 3/4 turn. Reinstall oil drain plug to 19 ft-lbs.
4. Add 12 quarts of 10W-30 or 5W-40 CK-4 diesel oil, idle 2 minutes, check level, and top off to full mark (13 quarts total).

Step 4 — Engine Air Filter Replacement (FA1927). 

1. Unclip the 4 airbox latches on passenger side; lift lid.
2. Pull dirty filter and vacuum out dust and leaves sitting in the airbox base.
3. Seat new FA1927 filter ensuring bottom indentations drop over airbox floor bumps and outer foam corner seats properly. Fasten 4 clips.

Step 5 — Key-ON Priming Sequence & Leak Check. 

1. Do NOT Crank Immediately! Turn ignition to RUN (without cranking) for 20 seconds. Repeat 8 to 10 times to let the lift pump purge all air from the fuel lines.
2. Start engine, inspect frame-rail separator, upper fuel filter, and oil filter for any fuel or oil weeping.
3. Reset `Oil Life Monitor` on dashboard.

Five Expensive Mistakes

Mistake #1: Buying one fuel element for a two-element service

The FD4625 is two elements in two locations. A single-can listing is half the job, and the half it omits is usually the water separator — the part that protects the pump. If the listing shows one fuel filter, keep looking.

Mistake #2: Reusing the housing O-rings

The fuel and oil housing seals are one-time-use. Heat cycling compresses them permanently, so a seal that looks fine will not seal on reinstall. Every genuine kit ships new O-rings. Use them, and if one is missing, stop and get one.

Mistake #3: Cranking an unprimed system

Air in a CP4.2 is as destructive as water. The pump relies on fuel for lubrication, and the fuel system needs to be bled with the lift pump before the engine turns over. Six to eight key cycles is a minute of your life; a pump is a five-figure repair.

Mistake #4: Installing the wrong year’s filter

FD4625 is 2017-2019. FD4615 is 2011-2016. The 2020+ trucks take a different air filter (FA2031) and, officially, a different oil filter number. The listings look the same, the housings do not. Confirm the year before you order.

Mistake #5: Buying an unrated fuel element to save $40

A white-label fuel element with no published micron rating and no water-separation layer is not the same product at a lower price — it is a different product with a different job description. On this engine the difference between a filter that protects and a filter that is just a can is exactly the difference between a normal service and a $12,000 one.

Frequently Asked Questions

What exactly is in this kit?

Three filters: the FD4625 dual-stage fuel filter set (frame-rail water separator element plus engine-bay fine element), the FL2051S oil filter, and the FA1927 engine air filter. The fuel elements ship with fresh O-rings.

What is the difference between FD4625 and FD4624?

FD4624 was the original number for the 2017 6.7L fuel filter. Motorcraft superseded it with FD4625, which uses updated filtration media. FD4625 is backward-compatible with all 2017-2019 applications. If a listing references FD4624, the FD4625 you are buying is the current correct part.

Is my air filter FA1927 or FA2031?

FA1927 is the 2017-2019 air filter. Starting with the 2020 model year the airbox changed and the filter became the FA2031. They do not interchange. The outer foam pre-filter on the FA1927 is the visual giveaway — the 2020+ element does not have it.

I have a 2020 truck — does this kit fit?

No. This kit is for 2017-2019. The 2020-and-newer 6.7L uses the FA2031 air filter and, officially, the FL2124S oil filter. The fuel filter is different as well. Match the kit to the year.

What is the difference between FL2051S and FL2124S?

FL2051S is the spin-on oil filter for the 2017-2019 6.7L. FL2124S is the current production number Motorcraft carries for the 2020-and-newer trucks. The two are thread-compatible and physically interchange — plenty of 2017-2019 owners, including the owner in the video this guide was checked against, run the FL2124S with no issue. Either threads on and seals correctly, which is why good kits list both cross-references.

How much oil does a 6.7L Powerstroke take?

Thirteen quarts with a filter change. The safe way to get there: add twelve quarts, start the engine and confirm oil pressure comes up, shut it off, then wait about five minutes for the oil to drain back into the pan before you check the dipstick. Add the thirteenth quart, wait a few minutes more, and recheck — you want the level at the top of the crosshatch. Overfilling aerates the oil and underfilling starves the turbo bearings, so trust the dipstick over the jug.

What oil should I run?

The filler cap on this generation reads “10W-30, or 5W-40 for severe duty.” Motorcraft 10W-30 is the factory fill; 5W-40 full synthetic is the common choice for heavy towing and hot climates. The oil has to meet the diesel spec for this engine — the spec is what protects it, not the brand on the jug.

How often should I change each filter?

Fuel filter every 15,000 miles, or every second oil change. Comfortable — Ford’s book allows up to 22,500 miles in ideal conditions, but most owners who tow or buy from low-turnover stations service at 15,000 and are not being wasteful. Oil filter at every oil change, which on this truck is 7,500 to 10,000 miles, shortened to 5,000 under heavy towing or long idling. Air filter at 30,000 miles, or 15,000 in dusty, off-road, or construction use — and treat 30,000 as the middle of a wide range, because highway trucks have run these elements out to 45,000 miles while dusty ones get changed at 10,000. That number assumes clean air: one owner who opened his airbox at 15,000 miles found it packed with dust and dead insects, and another at 30,000 miles found it loaded, both before the book interval. Inspect the element and the restriction indicator at each oil change and replace early if it is loaded.

Do I need the cabin filter too?

This kit does not include it. The FP92 cabin filter is the one most owners forget exists — it lives behind the glovebox and filters the air you breathe. If it is due, the four-filter kit adds it and closes out the service in one order.

How do I prime the fuel system after a filter change?

Key-start trucks: ignition to RUN without starting, hold it ten to thirty seconds, then off — repeat six to ten times. Push-button trucks: foot off the brake, press START twice to reach RUN, and let the pump cycle the same way. You will hear the tone change from a gurgle to a steady hum as the air clears. Do not crank until it settles. If you want to be extra careful, prime and leak-check after the frame-rail filter before you open the engine-bay housing — each housing fills on its own that way.

Can I do this in my driveway?

Yes. The frame-rail separator needs a 32mm socket, the engine-bay filter and the oil filter need standard hand tools, and the air filter is a matter of opening the airbox. Figure an hour for all three the first time, less once you have done it once.

Why is the Amazon kit $50 cheaper?

Because it is usually a different product. The cheap kits often ship a single fuel element instead of the two-element set, and they frequently skip the coalescing media that separates water — with no published micron rating to compare against. On this engine that is not a saving, it is a gamble with your pump.

What tools do I need?

A 32mm socket for the frame-rail fuel housing, a 16mm socket or wrench for the oil drain plug, oil filter pliers (or a strap wrench) for the spin-on oil filter, an 8mm socket with a short extension if your truck uses the five-bolt fuel housing, a socket set and a flathead screwdriver for the fuel system and the shield, a drain pan capable of holding at least 13 quarts, a clean funnel, brake cleaner, shop rags, and clean diesel or fresh oil to lubricate the new seals. No special tools.

How do I drain water from the fuel filter?

There is a yellow quarter-turn drain valve at the bottom of the frame-rail water separator. Open it with a catch pan underneath and let it run until the flow turns from water to clean fuel, then close it — the drain is a monthly maintenance item regardless of your filter interval, and draining it is what keeps water out of the housing between services. On this truck you can drain the separator without changing the filter, and you should.

How do I know if my truck has the bolt-on housing or the screw-off cap?

Get under the truck and look. The screw-off style has a large hex cap that takes a 32mm socket; the bolt-on style has five small 8mm fasteners around the perimeter of the housing and no hex cap. Both appear across the 2017-2019 range and both are covered in this guide’s install steps. If you see bolts, count five and use a star pattern at about 7 ft-lb on reassembly; if you see a hex, the cap comes off with a socket.

How do I reset the oil life monitor?

With the engine off, press the start button without your foot on the brake to bring up the dash. Use the steering-wheel arrows to reach Settings, then Advanced Settings, then Vehicle, then Oil Life Reset. Hold OK until the display reads 100 percent. On a key-start truck, turn the ignition to RUN without cranking and follow the same menu path. The truck has no way to know you changed the oil, so if you skip this, the monitor will still be counting down from where it was.

Get All Three Filters, in One Box

If your 2017-2019 6.7L Powerstroke is due for its fuel, oil, and air service — or the air filter is the one you keep meaning to get to — this kit closes the gap. One order puts the FD4625 dual-stage fuel set, the FL2051S oil filter, and the FA1927 air filter in a single box, matched to the truck and ready for one afternoon in the garage.

Get the 2017-2019 6.7L Powerstroke 3-Filter Kit

Want to confirm fitment against what other owners are running? A few threads worth reading:

• 2017-2025 6.7L Powerstroke Fuel Filter — Replaces FD4625
• 2011-2025 6.7L Powerstroke Oil Filter — Replaces FL2051S
• 2017-2019 6.7L Powerstroke Air Filter — Replaces FA1927

Legal Disclaimer

This guide is for general informational purposes only and is not a substitute for your vehicle’s factory service manual or the advice of a qualified diesel technician. Always verify the correct part numbers for your specific model year, VIN, and configuration before purchasing or installing filters. Installation of any aftermarket or replacement part is performed at your own risk; the author and retailer assume no liability for damage, injury, or loss arising from the use of this information or the products referenced. Filter change intervals are manufacturer recommendations and should be adjusted for your driving conditions, towing load, and fuel quality.