L5P|L5D Duramax Passenger Side Fuel Rail — GM 12721111

Genuine OEM GM high-pressure diesel fuel injection rail (RH / passenger side) for 2024–2026 6.6L L5P and L5D Duramax engines.

• Restores factory high-pressure fuel delivery to the passenger-bank injectors
• Direct replacement for GM part 12721111
• Correct 2024-2026 passenger rail — not interchangeable with 2017–2023 rail 12686808
• Matching driver-side rail for these years is a separate part (12731370)

What’s included

• Genuine GM passenger (RH) high-pressure fuel rail assembly
• Fuel rail pressure sensor (as supplied on the OE assembly)

Why replace the rail

• Cracked, leaking, or damaged rail
• Metal contamination after high-pressure pump failure
• Worn fittings or fuel pressure loss
• Full fuel-system rebuild (pump, lines, rails, injectors)

Fitment

• Engine: 6.6L Duramax L5P / L5D diesel
• Years: 2024–2026 (confirm with VIN for 2026 medium-duty applications)
• Position: Passenger / right-hand (RH) bank only

Typical applications:

• Chevrolet Silverado 2500HD / 3500HD
• GMC Sierra 2500HD / 3500HD
• Chevrolet Silverado 4500HD / 5500HD / 6500HD (L5D where equipped)

Features

• Genuine GM OEM — factory fit, ports, and sealing
• High-pressure common-rail construction for L5P/L5D
• Passenger-side rail with OE fuel pressure sensor
• Direct replacement for GM 12721111
• Built to GM durability and pressure-control specs

Installation notes

• Professional installation recommended
• Relieve fuel-system pressure before disconnecting lines
• Replace high-pressure lines, seals, and related hardware as needed
• After a contaminated-pump failure, replace both rails and flush or replace the rest of the high-pressure circuit