The BEST Fuel Filtration for the L5P Duramax

April 14, 2023

FASS Diesel Fuel System for L5P Duramax

Goodbye LML, hello L5P!

Whether packaged in a Chevrolet Silverado or GMC Sierra, the L5P Duramax is a seriously capable diesel engine. From daily driving and trailer-towing to sled pulling and drag racing, Duramax owners around the world are putting the L5P to work. Starting in 2017, General Motors introduced the L5P Duramax for the Silverado 2500/3500, and GMC Sierra 2500/3500. Though the outgoing LML Duramax was (and is) popular among GM truck fans, the L5P was simply more capable than its predecessors. 

Though improved power, efficiency, and stronger components gave the L5P Duramax an edge over older Duramax options—one could argue it rivaled the diesel options from Ram and Ford too. 


Is diesel fuel hurting your L5P Duramax?

It often comes as a surprise that diesel fuel can be heavily contaminated—right from the pump. Despite paying $5.00 or more per gallon, diesel fuel is poorly filtered, poisoning your Duramax’s injection system with entrained air/air vapor, water, and debris. 

Without proper filtration, wear, and tear caused by fuel contamination can lead to premature injection system failure! Ready for more good news? Repairs can cost THOUSANDS—a single injector can run $1,500 or more, and that’s without installation! Few L5P Duramax problems are as expensive, or common, as injection system failures. 


Does your L5P Duramax need a fuel filter upgrade?

Despite the Silverado and Sierra’s reputation as affordable trucks, Heavy Duty models equipped with the L5P Duramax don’t typically come cheap. Understandably, many owners look for ways to protect their investments beyond routine maintenance schedules. 

That’s where we come in. Since 2003, our team at FASS Diesel Fuel Systems has been designing, testing, and manufacturing the leading diesel filtration solutions. Most recently, our engineering team released the Drop-In Series Fuel System for the 2017+ L5P Duramax. This 100% bolt-in, plug-and-play filtration system protects the L5P’s injection system from premature wear and failure—potentially saving owners thousands of dollars in repair costs. 

Our Drop-In Series Fuel System provides next-level protection by:

  • Removing entrained and vapor
  • Eliminating over 99% of the water found in diesel fuel (3rd-party proven)
  • Filtering debris down to 2 Micron absolute
  • Increasing the lubricity of fuel by at least 10%
  • Retaining full functionality of the OEM water-in-fuel sensor 

Designed specifically for the L5P Duramax, our Drop-In Series Fuel Systems install in less than an hour, and require zero tuning or additional modifications

Improved MPG, horsepower, and more! 

Protecting your L5P Duramax from premature injection system wear is only half the story. It might surprise you to learn that properly filtering your diesel fuel has benefits far beyond reducing maintenance costs. 

By eliminating fuel contaminants, our Drop-In Series Fuel Systems correct injection timing and allow a more complete combustion cycle. This means you’ll get to enjoy:

  • Optimized MPG (results will vary) 
  • Restored horsepower 
  • Reduced DPF regens 
  • Reduced EGTs 
  • Sharper throttle response
  • And more! 

Additionally, we proudly manufacture our Drop-In Series Fuel Systems right here in Missouri and back them with a Limited Lifetime Warranty.

Not sure which fuel system upgrade is right for your Duramax? Call our team at (636) 433-5410, or shoot us an email at, and we’ll be happy to help! 


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FREEDOM SALE on all FASS Fuel Systems through 12/31/23