Description
Fuel Filter Housing Cap for 2017-2020 Duramax 6.6L L5P
The OEM plastic fuel filter housing cap on 2017-2020 Duramax 6.6L L5P engines is a known failure point — cracking, warping, and leaking under heat cycling and repeated service. Our CNC-machined billet 6061-T6 aluminum cap with black anodized finish eliminates this problem permanently. Replaces GM part number 134001.
Key Features
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CNC Billet 6061-T6 Aluminum — Precision machined from aircraft-grade aluminum, far stronger than the OEM injection-molded plastic cap.
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Black Anodized Finish — Corrosion-resistant coating stands up to diesel fuel, road salt, and under-hood heat cycling.
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OEM-Plus Design — Engineered to match factory fit and function while eliminating the cracking/leaking failure mode. Threads perfectly onto the stock filter housing.
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Complete Kit — Includes 1 billet aluminum cap and 1 drain plug. (O-ring sold separately or reuse existing.)
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Easy Install — Direct bolt-on replacement. No modifications, no special tools. 10-minute swap.
Compatibility
| Year |
Make |
Model |
Engine |
| 2017-2020 |
Chevy |
Silverado 2500HD |
6.6L V8 Diesel (L5P) |
| 2017-2020 |
Chevy |
Silverado 3500HD |
6.6L V8 Diesel (L5P) |
| 2017-2020 |
GMC |
Sierra 2500HD |
6.6L V8 Diesel (L5P) |
| 2017-2020 |
GMC |
Sierra 3500HD |
6.6L V8 Diesel (L5P) |
Specifications
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Material: CNC Billet 6061-T6 Aluminum
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Finish: Black Anodized
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Replaces OEM: 134001
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Package: 1x Housing Cap + 1x Drain Plug
Why Choose iFJF?
The OEM plastic cap on your Duramax 6.6L L5P sees extreme temperatures, diesel fuel exposure, and removal/reinstallation at every filter change. Over time, the plastic fatigues — and when it cracks, you lose fuel pressure, leak diesel, or get stranded. Our billet aluminum cap is a one-time upgrade that outlasts the truck. IATF 16949 certified manufacturing. Backed by our satisfaction guarantee.
Frequently Asked Questions
Q: Why does the OEM plastic cap fail?
A: The GM factory cap is injection-molded plastic that degrades under heat cycling and repeated removal. Diesel fuel exposure accelerates cracking. This is a well-documented problem on 2017-2020 L5P engines — many owners replace it preventatively.
Q: Is this a direct fit or do I need modifications?
A: Direct bolt-on replacement. The threads, sealing surface, and drain plug are precision-machined to match the factory housing exactly. No adapters, no modifications.
Q: Does this come with the O-ring?
A: The cap does not include the O-ring. We recommend reusing your existing O-ring if it's in good condition, or purchasing a new OEM O-ring separately.
Q: Will this fit a 2016 Duramax LML?
A: No. This cap is designed specifically for the 2017-2020 L5P fuel filter housing. LML (2011-2016) uses a different filter housing design.
Q: How do I install this?
A: Remove the old plastic cap with a 36mm socket, unscrew the drain plug, transfer it to the new cap, thread the new cap on hand-tight + 1/4 turn with the socket. Cycle the key 3-5 times to prime, then start and check for leaks. 10-minute job.
Q: What torque should I use?
A: Hand-tighten, then 1/4 turn with a 36mm socket. Approximately 18-22 ft-lbs. Do NOT overtighten — the aluminum threads are strong but the housing seal is what does the work.
