L5P Duramax Fuel Contamination Kit | Alliant Power AP54820

Complete high-pressure fuel system replacement for 2017–2019 Chevy Silverado and GMC Sierra 2500HD/3500HD 6.6L Duramax L5P trucks. When metal, water, DEF, or bad diesel contaminates an L5P, debris travels through the pump, rails, lines, and injectors. Replacing only the failed piece usually means another failure. AP54820 is the one-box, OE-style repair that replaces the contaminated high-pressure system so the truck can build rail pressure again.

Use this kit if you have a P0087 (fuel rail pressure too low) after a pump event, metallic debris in the filter, rails, or injectors, water, DEF, or microbial contamination in the fuel system, or a starved or seized high-pressure pump that sent shavings through the common rail.

Partial repairs leave contaminated hardware in the circuit, and leftover debris can score new nozzles and ruin a new pump. AP54820 is built as a full-system replacement with remanufactured injectors and pump, both rails, hard lines, feed/return plumbing, the 2017–2019 style fuel cooler, filter, and the gaskets/seals needed to finish the job. Components are OE or OE-equivalent, assembled in the USA in an ISO 9001:2015 facility, and end-of-line tested at 15 points for leak-free operation.

What’s in the box:

• (8) remanufactured common-rail injectors — OE #12698552 / 12678992 / 12696966
• (1) remanufactured common-rail injection pump — OE #12731367 / 12678993 / 12701094
• (1) left-hand fuel rail with rail pressure control valve — OE #12678991
• (1) right-hand fuel rail with rail pressure sensor — OE #12678990
• (8) rail-to-injector hard lines
• High-pressure supply lines (pump-to-rail and rail-to-rail)
• Fuel feed and return line set
• (8) injector hold-down bolts and fuel injection pump nut
• 2017–2019 style fuel cooler
• Metal-free diesel fuel filter element
• Low-pressure diesel hydrocarbon injector
• Throttle body, EGR, intake, cooler, and thermostat gaskets/seals
• Turbo air inlet adapter seal

Exact gasket and line count can vary slightly by kit revision; the kit is intended as a complete contamination repair package for the 2017–2019 L5P high-pressure system.

Features:

• Direct-fit replacement for the stock L5P common-rail system
• Complete one-box solution — no parts chasing across multiple suppliers
• 100% OE or OE-equivalent validated components
• USA assembled in an ISO 9001:2015 certified facility
• 15-point end-of-line testing for leak-free performance
• Built to help stop repeat failures from leftover contamination
• Backed by Alliant Power’s unlimited-mileage warranty (confirm current term at purchase)

Fitment:

• 2017–2019 Chevrolet Silverado 2500HD 6.6L Duramax L5P
• 2017–2019 Chevrolet Silverado 3500HD 6.6L Duramax L5P
• 2017–2019 GMC Sierra 2500HD 6.6L Duramax L5P
• 2017–2019 GMC Sierra 3500HD 6.6L Duramax L5P
• Includes the 2017–2019 style fuel cooler
• 2020+ L5P trucks typically need cooler 84740502 (or the cooler specified for that VIN) sourced separately
• Always verify fitment by VIN before ordering

Installation notes:

• Flush the tank, pickup, and low-pressure lines. New high-pressure parts will fail if dirty fuel is still in the truck.
• Replace remaining filters and consider a quality diesel additive with lubricity after the repair.
• Core return: 8 injectors, 1 pump, and both rails must come back in the manufacturer boxes for core credit. Incomplete or damaged cores can reduce or void the refund.
• Professional installation recommended. High-pressure diesel work requires a clean procedure and proper torque.