Improved Under Bed Filtration

If you’re looking to simplify primary fuel filter changes on the 6.7L Power Stroke in your ’17-’24 Super Duty, Fleece Performance Engineering has the answer. The company’s under bed fuel filter assembly replaces the factory, furnace style water separator with a Donaldson spin-on unit. Thanks to providing a new, direct replacement filter base with pre-installed fittings that seamlessly accept your truck’s factory quick-disconnect fuel lines, it makes for one of the quickest and cleanest installations on the market. Better yet, Fleece’s latest drop-in fuel system upgrade fits everything from the F-250 to the F-550.

What You’re Switching To

Though it looks quite a bit different, the Fleece Performance Engineering under bed fuel filter assembly is a direct, drop-in replacement for the factory water separator. In place of the factory, “furnace” style filter found in part numbers FD-4625, FD4625AA, HC3Z-9N184-C, and HC3Z-9N184-J, a Donaldson spin-on filter provides improved filtration. The spin-on style filter simplifies the water separator change interval, and does so by being a readily available, easy-to-install unit (PN P553203). A replacement Donaldson filter retails for just $24.99 through Fleece.

What’s In The Box

As we’ve come to expect from Fleece products over the years, the under bed fuel filter kit comes with high-quality components and everything you need to install it on your Super Duty. You get a fully assembled, billet-aluminum fuel filter base, the aforementioned spin-on Donaldson water separator, a water-in-fuel (WIF) sensor along with an electrical extension harness, and the necessary M6 mounting bolt. Additionally, the side of the filter base is designed to accommodate a fuel heater for customers that live in colder climates. As far as fitment goes, the Fleece under bed fuel filter assembly is compatible with all 2017-2024 model year F-250, F-350, F-450, and F-550 Super Duty’s, with either short bed or long bed configurations.

Billet-Aluminum Filter Base

Made from heavy-duty, anodized billet-aluminum that won’t rust or become brittle with time, the Fleece filter base ships with all feed and return fittings pre-installed. The anodized, billet-aluminum fittings seamlessly accept all four OEM quick-disconnect fuel lines. With the factory fuel lines disconnected and the OEM cartridge out of the way, the filter base installs using a mounting notch located on your late-model Super Duty’s underbody. Notice the heater provision on the top right as shown. This is where the filter base would integrate a heating element, which Fleece offers (here) and that comes with the required electrical harness to provide switched power to the heating element.

Proven Filtration And Water Separation

Regularly stocked by parts houses and online retailers alike, the Donaldson P553203 offers proven filtration and water separation performance. The filter itself uses a Twist&Drain valve, measures 7.6 inches in length (which is to say it hangs no lower than the factory filter cartridge does), and utilizes a 1-14 UN thread size. The Donaldson unit is also rated at 4 microns at 99-percent efficiency. This means the filter will remove 99-percent of all contaminants 4 microns in size and larger.

30-Minute Install

Here, the under bed fuel filter assembly is being installed on a short bed model Super Duty, where the filter is located at the front of the fuel tank. On long bed models, the filter assembly is mounted on the driver side of the fuel tank, facing the frame rail. Beyond the factory fuel tank(s), Fleece’s kit is compatible with aftermarket Titan and S&B replacement fuel tanks. Also notice that the supplied WIF sensor extension harness has been connected to the factory WIF sensor in the photo shown. All that’s left to do at this point is reinstall the OEM filter assembly guard, prime the fuel supply system by cycling the ignition to the “on” position two to three times, starting the engine, and checking for any leaks.

Primary And Secondary Fuel Filter Solutions

For maximum engine protection, Fleece’s under bed fuel filter kit can be combined with its engine mounted fuel filter assembly—the system that replaces the crack-prone OEM under hood fuel filter with a durable filter base and a 9-micron Donaldson filter. Both Fleece systems combined mean simplified filter changes, safer operation (at least as far as the engine mounted fuel filter assembly is concerned), and more affordable filter change intervals. Donaldson replacement filters for the Fleece systems total roughly half the cost of a genuine OEM Motorcraft fuel filter kit ($45-$55 vs. $90-$110).

Written by Mike McGlothlin