Under Bed Fuel Filter Upgrade For ’19-’24 Rams

Your fifth-gen Cummins was built for hard work, and so far it’s lived up to its billing. But the miles and operating hours are quickly racking up on your trusty workhorse—and so are the maintenance costs. Under the bed, a replacement water separator alone can run you more than $70. The plastic filter housing assembly it sits in? Upward of $130. Fleece Performance Engineering took note of the dilemma late-model 6.7L Cummins owners were facing and expanded its under bed fuel filter line to include 2019 to 2024 model year Ram 2500 and 3500’s. For trucks that rapidly accumulate miles on the odometer, it’s an upgrade that can pay for itself in short order.

What’s In The Box

As with any fuel system solution Fleece manufactures, the under bed fuel filter assembly for 2019-2024 Rams is an all-inclusive, direct replacement, and 100-percent bolt-on proposition. The kit includes a billet-aluminum filter base assembly, complete with pre-installed adapter fittings to accommodate the factory quick-connect fuel lines and the M8-1.25 x 20mm bolts required to mount it. A Donaldson spin-on water separator (PN P551329), which matches the performance of the factory Mopar unit (68436631AA), a water-in-fuel (WIF) sensor with water drain, and a water-in-fuel sensor adapter harness are also part of the comprehensive package.

Anodized Billet-Aluminum

Fleece’s billet filter base replaces the plastic OEM cartridge assembly (PN 68358393AA), and its aluminum construction is made more durable (as well as corrosion-resistant) thanks to being anodized. Notice that the pre-installed adapter fittings (also anodized aluminum) have the inlet and outlet labeled. On the other side of the filter base, Fleece includes a provision to install a fuel heater. Fleece says a high-flow fuel heater option will be available for its under bed fuel filter system beginning in August.

WIF Sensor & Adapter Harness

While the filter base is ready to bolt into place right out of the box, the water-in-fuel (WIF) sensor must be installed in the bottom of the Donaldson water separator. This is done by simply turning the water drain counterclockwise to remove it, and installing the supplied WIF sensor and water drain in its place. The Fleece WIF sensor adapter harness seamlessly integrates with the factory plug and effectively moves the WIF sensor to the bottom of the filter element.

The Under Bed, Inboard Location Of The System

Not only is the factory water separator assembly made of plastic on ’19-’24 Ram trucks, but it’s mounted upside down. This makes filter changes a bit messy no matter how long you drain the water separator prior to removing it. The cost of a replacement OEM water separator assembly (PN 68358393AA) can run you $130 or more, with replacement Mopar water separators retailing for upward of $65 (PN 68436631AA). Despite the upfront cost of $313.95 for Fleece’s under bed fuel filter system, the replacement Donaldson spin-on units the system uses can be had (through Fleece) for $22.99.

Quick, Easy Install

The straightforward install requires just three tools: a 13mm wrench, a flat head screwdriver, and a torque wrench. The 13mm wrench (or socket with ratchet) is employed to loosen the two factory mounting bolts for the OEM water separator assembly, which are discarded. The 13mm wrench is then used to tighten the two M8-1.25 x 20mm mounting bolts supplied in the Fleece kit. The mounting location remains the same, and the mounting bolts call for a 10 ft-lb torque spec.

30 Minutes Or Less

Thanks to no cutting being required, and effortless integration with the fuel lines, the Fleece under bed fuel filter assembly can be in place under a ’19-’24 Ram in 30 minutes or less. The final steps of the install call for reconnecting the truck’s batteries, priming the fuel system by cycling the ignition to the “On” position (without starting the engine) and waiting 5-6 seconds. This same priming process should be repeated two more times to purge all air from the low-pressure supply fuel system. Then the vehicle can be started and checked for any leaks.

Written by Mike McGlothlin