Best Automotive Replacement Fuel Tank Caps (2026 Guide)
We selected products using average customer rating, total review volume and feature relevance for common vehicle applications (fitment, material, locking, DEF compatibility)
The Verdict
- Best Overall: RAM Diesel Fuel Cap + DEF Cap Combo (2013-2018) Easy Grip — Best for Ram diesel owners needing both fuel and DEF caps with easy-grip and magnetic alignment
- Best Value: DOCA Diesel Cap for Dodge Ram 2019-2025 — Best for recent Dodge Ram models requiring a cap designed for capless fuel systems and diesel use
This guide compares top-rated automotive replacement fuel tank caps and related filler caps for a range of cars and diesel trucks, highlighting key features like locking, magnetic closure, OEM fit and aluminum construction. Picks were selected by combined product rating, review volume and feature relevance for common makes (Ram, Dodge, Toyota, Honda, GM)
Top Picks
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1
Best Overall RAM Diesel Fuel Cap + DEF Cap Combo (2013-2018) Easy Grip
Best for Ram diesel owners needing both fuel and DEF caps with easy-grip and magnetic alignment
Combo pack with a magnetic RAM diesel fuel cap and DEF cap. Keeps dirt and water out of the fill, with a smooth, easy-to-grip DEF cap and durable aluminum construction. Customers note secure magnetic attachment and OEM-like fit
- magnetic retention on metal surfaces
- two-cap combo for fuel and DEF
- rust-resistant aluminum with color anodizing
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2
Best Value DOCA Diesel Cap for Dodge Ram 2019-2025
Best for recent Dodge Ram models requiring a cap designed for capless fuel systems and diesel use
Diesel fuel cap designed for Dodge Ram trucks with capless fuel systems. Provides airtight, dust and water resistance for the fuel system. Customer note: strong fit and build, with mixed feedback on lockability and magnet strength
- Diesel-cap compatibility
- Airtight, dust & water protection
- Heavy-duty construction with good fit
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3
Aluminum Diesel Cap for 2019-2021 Dodge Ram 6.7L
Best for those who want a lightweight aluminum diesel filler cap tailored to 6.7L Ram engines
Diesel fuel cap with precise seal to keep dust, water, and debris out. Notable for fit on 2019-2021 Ram diesel models; customer notes strong appearance and secure fit with some difficulty in removal
- precision seal keeps out dust and moisture
- specific fit for 2019-2021 Ram diesel trucks
- alk aluminum construction for durability
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4
Fuel filter housing cap for Ram/Cummins 68065612AA
Best for replacing the fuel filter housing cap on Ram/Cummins setups with a direct-fit part
CNC billet aluminum fuel filter housing cap compatible with 2011-2024 Ram 6.7L and 2010 Dodge Ram diesel engines. Notches for a secure fit and leak prevention; includes cap only. Customer insight notes sturdy build and easy installation, with some concerns about thread scratches and sealing surface durability
- all-metal billet build
- accurate fit for 2011-2024 Ram 6.7L
- leak-prevention design
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5
Cap Assy, Fuel Tank (Toyota OEM)
Best for Toyota owners seeking a factory-style fuel tank cap with OEM fit and specifications
Fuel tank cap assembly, OEM Toyota quality and vehicle-specific fit. Customers say it snaps in place with easy installation and matches their vehicle, though some report leak concerns in the seal
- genuine OEM part
- vehicle-specific compatibility
- easy snap-in installation
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6
Honda Genuine Fuel Filler Cap 17670-T3W-A01
Best for Honda drivers who prefer a genuine manufacturer fuel filler cap for exact fitment
Genuine OEM fuel filler cap designed for exact fit and durability. Consumers note authentic Honda quality and fit, with some praise for improved gas mileage and easy installation; a few report tether attachment issues
- genuine oem part
- exact fit
- durable
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7
Aluminum DIESEL Cap for 2019-2021 Dodge Ram 6.7L
Best for customers wanting an aluminum diesel fuel cap option specifically for 6.7L Ram years listed
Diesel fuel cap with airtight, precision fit to protect the fuel system. Made from anodized billet aluminum for durability; fits 2019-2021 Ram diesel trucks. Customer notes it fits well and keeps dust and water out
- diesel-specific fit
- durable aluminum design
- fuel protection from elements
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8
Dodge Ram Diesel Fuel Cap (2019-2025) Aluminum Magnetic Cap
Best for Dodge Ram users who want an aluminum magnetic fuel cap for easier alignment and durability
Aluminum diesel fuel cap with built-in magnet and rubber seal. Helps keep dust out and attaches to the body while refueling. Customer notes fit on GMC 1500 diesel models and quality construction
- magnetic fuel cap
- dust-sealing rubber ring
- aluminum alloy cap
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9
GM Genuine Parts locking fuel tank cap with 2 keys
Best for GM owners needing a locking fuel tank cap solution that includes two keys for security
Locking fuel tank cap engineered for a tight seal with a tamper-resistant lock. GM OE specification for fit and reliability; customers note solid functionality and value for money
- lockable design
- GM OE fit
- two keys included
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10
Fuel Filter Housing Cap for GM Duramax 6.6L L5P (2017-2024) billet aluminum
Best for Duramax owners looking for a billet aluminum fuel filter housing cap for 6.6L L5P engines
Replaceable billet aluminum fuel filter housing cap for GM Duramax L5P. Stronger than OEM, with drain plug; includes cap and drain plug (O-ring not included)
- Billet aluminum for durability
- Direct replacement part number 134001
- Reinforced housing to resist cracking