L5P Duramax Billet Filter Cap Kit | FASS BFC1001K

Replace the factory plastic L5P fuel-filter cap before it rounds off or cracks. The FASS BFC1001K is a 6061 billet aluminum cap kit for 2017–2025 6.6L Duramax L5P trucks. It uses the same 36mm socket as stock, adds a tool-free billet drain valve, and works on both the OEM plastic housing and a FASS Drop-In Series system. Made in the USA.

Key features

• 6061 billet aluminum cap, machined in the USA
• Replaces the OEM plastic fuel-filter cap
• Same 36mm hex as the factory cap
• Billet drain valve for tool-free draining
• 1/8-inch female NPT port on the drain valve for an optional barb fitting
• Works with the factory plastic filter housing
• Works with FASS L5P Drop-In Series systems (DIFSL5P1001 / DIFSL5P2001)
• Helps prevent rounded hex flats and cold-weather cap cracks

Fitment

• 2017–2025 Chevrolet Silverado 2500HD / 3500HD 6.6L Duramax L5P
• 2017–2025 GMC Sierra 2500HD / 3500HD 6.6L Duramax L5P

Fits the stock water-separator / fuel-filter housing and FASS Drop-In Series housings.

What’s in the box

• FASS L5P billet filter cap
• Billet drain valve
• O-ring

Install the o-ring supplied with the replacement fuel filter in the cap groove during filter service.

Notes & specs

• Brand/part number: FASS BFC1001K
• UPC: 850044137350
• Engine: 6.6L Duramax L5P
• Material: 6061 billet aluminum
• Removal tool: 36mm socket
• Drain port: 1/8-inch female NPT
• Compatible systems: OEM housing and FASS Drop-In Series

This is a cap kit only. It does not include a filter, housing, or Drop-In Series system. If the plastic L5P cap is rounding off during service or you want a drain valve that does not need tools, the FASS BFC1001K billet filter cap kit is the direct upgrade.