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.

• FASS Drop-In Technology was developed to achieve industry-leading filtration with the simplest possible installation—making our Drop-In Series Systems a true bolt-in upgrade. If you’re mechanically inclined, a Drop-In Series Fuel System can be installed in your driveway in less than an hour! But don’t let the easy installation fool you—our Drop-In Series Fuel Systems offer the same world-class filtration as our Titanium Signature Series and Industrial Series lines.
• Performance Radius Cuts (PRC) are an advanced machining technique used to improve the flow of fuel through the FASS System by creating smooth-flowing cuts within the aluminum housing. This prevents the reintroduction of air and vapor back into the fuel and prevents eddy currents from forming within the corner of a 90-degree sharp angle. FASS Drop-In Fuel Systems are the only Fuel Air Separation System that incorporates these exclusive Performance Radius Cuts, lesser competitors commonly use T-Bone and square 90-degree fittings that can limit fuel flow, cause restrictions and reintroduce air back into your fuel.

Please Note: This plug-and-play filtration system utilizes the L5P Duramax OEM in-tank fuel pump for fuel flow.

• The only drop-in L5P filtration system that retains full functionality of the water-in-fuel sensor!
• The only drop-in L5P filtration system with air separation!
• Increases lubricity of the fuel by up to 10% by removing entrained air and air vapor.
• Extends the life of fuel injection system components.
• Over 99% free and emulsified water separation with our Extreme Water Separator technology.
• 2 Micron absolute filtration rating.
• 100% drop-In, no additional modifications needed.
• Retains the factory in-tank lift pump.
• Works with the factory plastic cap or billet filter cap.