The FASS Drop-In Series Diesel Fuel System was engineered by FASS to be the most effective filtration solution for the L5P Duramax. Backed by our limited lifetime warranty, the Drop-In Series Fuel System protects your L5P Duramax from the issues caused by fuel contamination.

Without proper fuel filtration, modern diesel injection systems are prone to excessive wear, which can cost THOUSANDS! By removing over 99% of the water from your diesel fuel, along with entrained air and debris down to 2 Microns, the Drop-In Series System protects the L5P’s injection system from premature failure.

Additionally, by eliminating the contaminants mentioned above, our Drop-In Series System for the L5P Duramax optimizes MPG (results will vary), restores horsepower, and sharpens throttle response.

And if reliability, optimized MPG, restored horsepower, and a sharper throttle response isn’t enough, this system can be installed in an hour or less! This is a true plug-and-play system, requiring no cutting, wiring, or additional modifications. Better still, this system requires ZERO tuning changes! Whether your L5P is stock or modified, our Drop-In Series Systems will not require adjusting tunes or clearing any codes.

Our industry-leading water removal capabilities (3rd-party proven to exceed 99%) are reinforced by the unique design of our Extreme Water Separator (XWS). If our XWS reaches capacity, it acts as a dam, shutting down your truck and preventing major destruction of fuel system components.