Best Automotive Replacement Fuel Tank Caps Under $100 (2026)
We prioritized parts under $100 with clear vehicle compatibility, durable construction (aluminum/OEM), useful features (locking, magnetic, DEF combos), and strong value scores
The Verdict
- Best Overall: RAM Diesel Fuel Cap + DEF Cap Combo (2013-2018) Easy Grip — Best diesel combo cap: useful RAM diesel and DEF cap combo that simplifies replacements with ergonomic grip and dual-cap functionality
- Best Value: DOCA Diesel Cap for Dodge Ram 2019-2025 — Best for newer Rams: designed for Dodge Ram 2019–2025 fitment and capless systems to restore proper diesel fuel sealing
This guide covers practical, vehicle-compatible replacement fuel tank caps and related filler or filter housing caps priced under $100, focused on fit, material, and functionality for common makes and diesel applications. Picks were chosen by comparing compatibility data, construction (aluminum, billet, OEM), locking or magnetic features, and overall value for repair or upgrade needs
Top Picks
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1
Best Overall RAM Diesel Fuel Cap + DEF Cap Combo (2013-2018) Easy Grip
Best diesel combo cap: useful RAM diesel and DEF cap combo that simplifies replacements with ergonomic grip and dual-cap functionality
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 newer Rams: designed for Dodge Ram 2019–2025 fitment and capless systems to restore proper diesel fuel sealing
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 lightweight upgrade: aluminum construction tailored to 2019–2021 Ram 6.7L applications for added durability and style
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 fuel-system part fit: direct-fit fuel filter housing cap for Ram/Cummins 68065612AA applications to maintain system integrity
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 OEM replacement for Toyotas: factory-fit fuel tank cap engineered for original-spec sealing and compatibility
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 OEM for Hondas: genuine filler cap that preserves factory sealing and emissions-system calibration
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 durable diesel appearance: aluminum diesel cap built for 2019–2021 Ram 6.7L use offering corrosion resistance
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 magnetic aluminum option: aluminum magnetic cap for Dodge Ram 2019–2025 that balances secure fit with quick access
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 locking security option: locking fuel tank cap with two keys providing theft deterrence and standard fitment
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 billet fuel filter cap: billet aluminum housing cap for GM Duramax 6.6L L5P designed for robust service in diesel systems
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