Published by SayParts | Ford Diesel Parts Experts
Motorcraft FD-4647 Fuel Water Separator Filter — The Complete Guide for 2017–2025 Ford F-250 & F-350 6.7L Powerstroke Owners
If you own a 2017–2025 Ford F-250 or F-350 Super Duty with the 6.7L Powerstroke diesel engine, keeping your fuel water separator filter fresh is one of the most important maintenance tasks you can do. Neglecting it can lead to expensive injector damage, hard starting, and reduced power. The Motorcraft FD-4647 is the genuine OEM replacement filter — and in this guide, we'll explain everything you need to know.
What is the fuel water separator filter?
Diesel fuel naturally attracts water, and water in your fuel system is extremely damaging to your 6.7L Powerstroke's high-pressure fuel injectors. The fuel water separator filter does two jobs:
Separates water from diesel fuel before it reaches the injection system
Filters out particles 20 microns or larger — removing 99.9% of contaminants
The FD-4647 is a two-piece service kit that addresses both the in-tank fuel water separator and the engine-mounted fuel filter — a complete fuel filtration service in one part number.
Why genuine Motorcraft FD-4647?
The 6.7L Powerstroke runs at extremely high fuel pressures — up to 30,000 PSI at the injectors. This means fuel cleanliness is critical. Here's why the genuine Motorcraft filter matters:
99.9% filtration efficiency for particles 20 microns or larger
300-series stainless steel case for excellent corrosion resistance
Brazed connector and support washers for enhanced durability
Flex fuel compatible where required
Motorcraft 2-year / unlimited mile warranty — backed by Ford Motor Company
The only filter recommended by Ford for your 6.7L Powerstroke
Symptoms of a clogged or failing fuel filter
Hard starting or extended cranking before the engine fires
Engine stalling, especially under load
Hesitation or stumbling during acceleration
Reduced power, especially when towing or hauling
Water-in-fuel warning light on your dashboard
Rough idle or excessive smoke
If you're experiencing any of these symptoms, replace the FD-4647 immediately. Running a clogged fuel filter can starve your injectors of fuel and cause permanent damage.
How often should you replace it?
Ford's recommended service interval for the fuel water separator filter on the 6.7L Powerstroke is:
Every 15,000 miles under normal conditions
Every 10,000 miles if towing, hauling, or operating in dusty or wet conditions
Immediately if the water-in-fuel warning light comes on
Part numbers and compatibility
Part number Description Notes
FD-4647 Current OEM part 2017–2025 6.7L Powerstroke
FD-4641 Superseded Replaced by FD-4647
FD-4646 Cross reference Same application
FD-4625-AA Cross reference Same application
HC3-9N-184-J Ford OEM number Same part
Vehicle compatibility: 2017–2025 Ford F-250 Super Duty 6.7L Powerstroke Diesel and 2017–2025 Ford F-350 Super Duty 6.7L Powerstroke Diesel.
How to replace the FD-4647
Replacing the FD-4647 is a straightforward service job that most F-250/F-350 owners can do themselves:
Locate the fuel filter housing on the engine (driver side, near the fuel rail)
Place a drain pan under the filter housing to catch any spilled fuel
Drain the water separator bowl using the drain valve at the bottom
Remove the filter housing cap and pull out the old filter element
Install the new FD-4647 filter element
Reinstall the housing cap, hand tight plus a quarter turn
Prime the fuel system and start the engine — check for leaks
Every order from SayParts includes our FREE step-by-step installation video covering the complete FD-4647 replacement process on your 6.7L Powerstroke.
Why buy from SayParts?
Genuine Motorcraft FD-4647 with 2-year/unlimited mile Ford warranty
Free installation video — step-by-step guide for your 6.7L Powerstroke
Free worldwide shipping — ships fast from the US
Save vs MSRP — $109.99 vs $136.35 MSRP
VIN verification — confirm fitment before ordering
Don't risk expensive injector damage from contaminated fuel. The Motorcraft FD-4647 is the correct OEM fuel water separator filter for your 2017–2025 Ford F-250/F-350 6.7L Powerstroke — and it installs in under 30 minutes.
Fits 2017–2025 Ford F-250 & F-350 Super Duty 6.7L Powerstroke Diesel only. Verify fitment with VIN before ordering.
Don't risk expensive injector damage from contaminated fuel. Order the genuine Motorcraft FD-4647 today and get your free installation video with every order. 👉 Order the Motorcraft FD-4647 at SayParts — Click Here