Alliant AP0131 L5P|L5D Duramax Fuel Injector Installation Kit — Cylinders 2, 4, 5 & 7

Replace L5P/L5D injectors the right way. The Alliant AP0131 kit gives you the high-pressure fuel line and seals needed for a leak-free install on cylinders 2, 4, 5, and 7.

This is a single-injector kit (one kit per injector). The high-pressure lines on the 6.6L Duramax L5P/L5D are two different shapes, so AP0131 covers cylinders 2/4/5/7 and AP0132 covers 1/3/6/8. Use the correct kit for the cylinder you are servicing.

What’s included

• High-pressure injector fuel line
• Injector body O-ring
• Injector chamber gasket (copper washer)

These are the wear items that should be replaced whenever an injector is removed or installed. Reusing old lines and seals is a common cause of leaks and hard starts.

Why this kit

• Built to OEM specifications for first-time fit
• Direct replacement for GM service parts
• Designed for both shop techs and DIY installs
• Helps restore proper high-pressure fuel routing and sealing

Alliant Power is a major diesel aftermarket supplier known for OEM-spec fuel-system components. This kit is intended to deliver factory-like sealing without the dealer-only parts markup.

Vehicle fitment

• 2017–2026 Chevrolet Silverado / GMC Sierra 2500HD & 3500HD — 6.6L Duramax L5P
• 2019–2026 Chevrolet / GMC 4500HD, 5500HD, 6500HD and International CV — 6.6L Duramax L5D (cab & chassis)

Always confirm cylinder number before ordering. Passenger-side odd cylinders and driver-side even cylinders use different line shapes.

Installation notes

• Sold individually — order one AP0131 per injector on cylinders 2, 4, 5, or 7
• For a full set of 8 injectors you typically need four AP0131 and four AP0132
• Replace the line and seals anytime an injector is pulled
• Torque and routing must follow factory procedure; these lines run at very high pressure

Cross references

AP0131, APP40638, 12685923, 12687229, 12720156, 904042, 904-042