Locking Gas Cap W/2 Keys
4.1Editor score
Replaces three common part numbers
Two keys included
Broad Toyota compatibility
Direct, tool-free installation
In this guide
A locking gas cap with keys adds a practical layer of protection against fuel theft and unauthorized access to a vehicle’s fuel system. The right replacement should also seal properly, resist corrosion and weather, match the original part numbers, and install without special tools. Compatibility is the most important consideration.
The products in this guide were compared using their supplied specifications, customer ratings, replacement numbers, included keys, materials, sealing claims, vehicle compatibility, installation methods, and intended applications. The list includes direct-fit replacements, universal-style caps, a vented all-metal design, and genuine or OEM-branded options for different vehicle families.
Each review explains where a locking gas cap with keys is strongest, what trade-offs buyers should consider, and which drivers may be best served. Product ratings are included for quick reference, while compatibility must be confirmed before buying. Availability and prices can change, so compare current listings and fitment details carefully.
Top 3 Picks for Best Locking Gas Cap with Keys
GM Genuine Parts GT264
4.4Editor score
GM-recommended replacement
Tight quarter-turn seal
Two keys included
Manufactured to GM standards
United Pacific S1301
3.9Editor score
All-metal vented construction
Triple-chrome finish
Two keys included
Classic vehicle applications
Top 10 Best Locking Gas Cap with Keys in 2026 Compared
This side-by-side comparison covers locking caps offered for Toyota, GM, Chrysler, classic Chevy and Ford vehicles, and several broad-fit applications. Compare part numbers, sealing systems, lock mechanisms, materials, included keys, and vehicle fitment before making a final selection.
ProductsSpecificationsEditor scorePrice
Best Budget
Locking Gas Cap W/2 Keys
ABS and rubber construction
Two keys included
Replaces 10504 and 31780
Toyota and broader applications
4.1Editor score
Editor's Choice
Locking Gas Cap Fuel Tank with Key
ABS and rubber construction
Two keys included
Replaces three common numbers
Not suitable for diesel
3.5Editor score
Best Premium
United Pacific S1301
All-metal vented design
Triple-chrome finish
Two keys included
Classic Chevy and Ford fits
3.9Editor score
ABS Anti-Theft Fuel Tank Lock
ABS and rubber construction
Two keys included
Replaces 10504 and 31780
Broad vehicle compatibility
3.1Editor score
Car Locking Gas Cap
ABS plastic construction
Two keys included
Replaces OEM 12495845
Multi-brand vehicle applications
3.1Editor score
GM Genuine Parts GT264
GM original equipment branding
Two keys included
Quarter-turn locking design
Tight fuel tank seal
4.4Editor score
Gates 31828
Heavy-duty construction
Two keys included
Quarter-turn key operation
Fuel-resistant rubber seals
4.2Editor score
Keyed Alike Locking Fuel Cap
Keyed-alike lock design
Durable long-life materials
Emission-control tested
Theft and vandalism deterrence
4.3Editor score
Gates 31670
Heavy-duty construction
Two keys included
Quarter-turn key operation
Fuel-resistant rubber seals
4.0Editor score
Locking Gas Cap for Chrysler
Dodge and Chrysler applications
Replaces two factory numbers
Mechanical key lock
Wide model compatibility
4.4Editor score
1. Locking Gas Cap W/2 Keys – Broad Toyota Compatibility
Locking Gas Cap W/2 Keys
ABS plastic and rubber
Two included keys
Three replacement part numbers
Tool-free direct installation
This locking gas cap with keys earns a 4.1 customer rating and stands out as an affordable replacement option for several common Toyota and other vehicles. It includes two keys and is designed to replace part numbers 10504, 31780, and 77300-47020, making it a relevant choice for owners who can match one of those identifiers to their original cap.
Pros
- Broad listed vehicle coverage
- Two keys reduce lockout risk
- Replaces common factory numbers
- Simple installation process
Cons
- Compatibility requires careful checking
- Vehicle list is not exhaustive
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Its strongest features are the broad listed fitment, direct replacement format, and simple installation. The product information lists applications across 4Runner, Avalon, Camry, Corolla, FJ Cruiser, Highlander, Matrix, RAV4, Sequoia, Sienna, Tacoma, and additional models. The cap uses a locking mechanism intended to deter fuel theft while maintaining a tight seal that helps control vapor emissions and fuel loss.
The main trade-off is that compatibility cannot be guaranteed from a general vehicle make or model alone. Some caps look similar but differ in thread, diameter, depth, venting, cam profile, and emissions-system design. Buyers should confirm both the replacement number and the physical dimensions before removing the original cap. The two included keys are useful, but key storage in a secure location remains important.
This is a strong recommendation for a Toyota or cross-compatible vehicle owner seeking a straightforward keyed replacement with useful part-number references. It is particularly appealing when the existing cap is damaged, loose, or no longer locks properly. Verify the listed fitment and compare the original cap before ordering, especially if the vehicle has an unusual fuel-filler arrangement.
Practical Compatibility Checking
Begin with the replacement numbers printed or molded into the existing cap, then compare them with 10504, 31780, and 77300-47020. Confirm the listed model year and check thread size, cap diameter, and whether the vehicle requires venting or a specific emissions-style cam.
Security With Spare Key Access
Two keys are included, reducing the inconvenience of a single lost or damaged key. Keep one in a safe household location and the other accessible only when needed, rather than leaving a spare permanently inside the vehicle.
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2. Locking Gas Cap Fuel Tank with Key – Wide Multi-Brand Fit
Locking Gas Cap Fuel Tank with Key
ABS plastic and rubber
Two included keys
Replaces three common numbers
Excludes diesel vehicles
This keyed fuel cap has a 3.5 rating, making it one of the less highly rated options in this roundup, but it offers an unusually broad list of vehicle applications. It is advertised for Toyota, Chevrolet, Nissan, GMC, Honda, Acura, Infiniti, Buick, Saturn, Isuzu, Mazda, Volkswagen, Mitsubishi, Scion, Suzuki, Cadillac, Pontiac, Saab, Audi, and Volvo vehicles.
Pros
- Impressive multi-brand compatibility
- Two keys supplied
- Waterproof and corrosion resistant
- Easy twist-to-click installation
Cons
- Lowest customer rating
- Not intended for diesel vehicles
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The cap is made from ABS plastic and rubber, with sealing, corrosion resistance, and waterproofing identified as core design features. Two keys are included. Installation follows a familiar process: remove the old cap, align the replacement, and twist until a click indicates it is seated. The stated replacement numbers are 10504, 31780, and 77300-47020.
Its broad compatibility is useful, but it also makes careful verification essential. The product explicitly says that not all vehicles are listed and advises checking the original part number. It is also not suitable for diesel vehicles. The 3.5 rating suggests some buyers may have encountered fitment, finish, or installation concerns, although the supplied information does not identify specific customer complaints.
Choose this option if your vehicle appears in the compatibility details and the listed part numbers match. It may be especially appealing to owners comparing several common replacement numbers across older trucks, SUVs, and sedans. Do not rely on the brand list alone, and avoid fitting it to a diesel fuel system or a vehicle with a different locking profile.
A Broad Cross-Brand Replacement
The extensive brand coverage makes this option useful when searching for a common fuel cap shared by several manufacturers. The listing’s explicit warning that not every vehicle is included reinforces the need to compare the original part number before purchase.
A Sealed Plastic-and-Rubber Design
ABS plastic provides a lightweight structural shell, while the rubber sealing element is intended to resist fuel penetration and maintain a secure closure. Proper seating is essential for the seal to perform as designed.
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3. United Pacific S1301 – Premium Chrome Restoration Style
United Pacific S1301
All-metal vented construction
Triple-chrome plated finish
Two included keys
Classic vehicle fitments
The United Pacific S1301 carries a 3.9 rating and differentiates itself with an all-metal, vented design covered in a triple-chrome finish. It is aimed especially at owners restoring or maintaining older Chevrolet and Ford vehicles, combining a period-appropriate appearance with the practical security of a keyed cap.
Pros
- Distinctive triple-chrome appearance
- All-metal construction
- Vented design for classic applications
- Two keys included
Cons
- Focused on older vehicles
- Only one cap per order
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The listed applications include 1947-71 Chevrolet and GMC trucks, 1949-70 Ford cars, and 1957-70 Ford trucks and Broncos. Its metal construction and bright chrome finish suit restoration and customization priorities, while the venting feature may be important where the original fuel system uses a vented cap format. One cap and two keys are included in the package.
Compatibility is narrower than that of several universal-style listings, but that focus reduces the temptation to force the part onto an unrelated vehicle. The 3.9 rating indicates a generally positive reception, though buyers should still verify the required thread and flange details for their specific year and model. Only one cap is included, so multiple-cap orders require separate purchases.
This is an appealing choice for classic Chevy or Ford owners who want a functional locking cap with a polished restoration look. It is less appropriate for a modern vehicle requiring a specific emissions cap profile. Confirm the original cap’s dimensions and venting arrangement, and treat the chrome finish as a deliberate aesthetic upgrade rather than a universal fit.
Restoration-Ready Visual Appeal
The triple-chrome finish gives the cap a bright, show-focused appearance that can complement restored trucks, coupes, and Broncos. Its metal shell also creates a strong visual contrast with common black aftermarket caps.
Purpose-Built for Vintage Applications
The vented format and listed classic-vehicle ranges make this more purposeful than a broad universal substitute. Confirm that the original cap was also vented and compare its mounting dimensions before purchase.
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4. ABS Anti-Theft Fuel Tank Lock – Security-Focused Universal Style
ABS Anti-Theft Fuel Tank Lock
Molded mechanical lock cylinder
Two included keys
Replaces three part numbers
Weather and temperature resistant
This locking fuel cap has a 3.1 rating and is positioned as an anti-theft replacement for part numbers 10504, 31780, and 77300-47020. Its lock cylinder is molded into the cap, and the package includes the cap and two keys. The design focuses on preventing unauthorized tank access while providing a replacement that can be installed directly.
Pros
- Dedicated mechanical key lock
- Seal and cap supplied together
- Two keys included
- Simple replacement procedure
Cons
- Lowest rating in the guide
- Broad fit language needs verification
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The listed material combination is ABS plastic and rubber sealing rings. The product information describes the cap as waterproof, dustproof, leakproof, flame-retardant, and impact resistant, with resistance to high and low temperatures. Its Toyota compatibility list includes 4Runner, Avalon, Camry, Corolla, FJ Cruiser, Highlander, Matrix, Sequoia, Sienna, and Tacoma applications.
The rating is the clearest drawback, although the supplied data does not explain whether concerns involve fit, finish, noise, or another issue. Buyers should be especially cautious with the word “universal” because fuel caps are safety-related and can differ in thread pitch, sealing depth, venting, and lock size. Comparing dimensions and part numbers is more dependable than relying on the broad application description.
The product may suit an owner who has confirmed exact compatibility and wants a basic keyed replacement with two keys. Its molded lock, replacement-number references, and straightforward installation are useful attributes. However, it is not the strongest recommendation for a buyer who prioritizes a long-established original-equipment brand or extensive published fitment guidance.
Mechanical Theft Deterrence
A dedicated key is required to open the cap, discouraging casual attempts to remove it and access the fuel tank. This deterrent is most useful in locations where fuel theft or vandalism is a recurring concern.
One-Step Seal Replacement
Combining the cap, rubber seal, lock cylinder, and keys simplifies replacement of a worn original assembly. Correct tightening remains necessary to obtain the intended leak-resistant seal.
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5. Car Locking Gas Cap – Durable Replacement for Multiple Brands
Car Locking Gas Cap
ABS plastic construction
Two included keys
Replaces OEM 12495845
Tool-free installation
This car locking gas cap has a 3.1 rating and targets a specific OEM replacement number, 12495845, while also listing several broader vehicle applications. It is built from ABS plastic with a locking system and dedicated key, offering a practical theft deterrent without introducing complicated powered components.
Pros
- Scratch-resistant ABS shell
- Sealed design resists dust and water
- Two keys provide backup
- Clear replacement part number
Cons
- Low customer rating
- Some listed applications are older
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The stated applications span older Isuzu, Acura, Honda, Chevrolet, Pontiac, and Mazda vehicles, including selected Prelude, Civic, CR-V, Bonneville, LeSabre, and Miata models. The product information emphasizes structural toughness, scratch resistance, and resistance to deformation. Its sealed design is intended to limit fuel vapor escape and help block water and dust from entering the tank.
Its 3.1 rating makes this a less confident overall recommendation than the highly rated Gates and GM options. The fitment list is also confusing because it combines model names and broad year ranges without a compact fitment chart. A matching OEM number is helpful, but it should be checked against the cap physically installed on the vehicle. The supplied information does not provide specific customer complaints, so avoid assigning an unverified cause to the rating.
Consider this cap when the original component carries OEM number 12495845 and its dimensions match the replacement. It is a practical option for owners of the listed older vehicles who value a keyed design, two supplied keys, and straightforward clockwise installation without special tools. Verify fit carefully before removing the working original cap.
Stable, Scratch-Resistant Housing
The ABS shell is described as hard enough to resist everyday scratches while retaining toughness under handling. It avoids the heavier construction of an all-metal cap while providing a durable keyed housing.
Protection Against Contamination
The tight-fitting design is intended to reduce vapor leakage and restrict entry of dust and water. Keep the sealing surfaces clean and avoid cross-threading the cap during installation.
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6. GM Genuine Parts GT264 – Trusted Original-Equipment Choice
GM Genuine Parts GT264
GM original equipment branding
Two included keys
Quarter-turn locking action
Tight fuel tank seal
The GM Genuine Parts GT264 is our Editor’s Choice and carries a 4.4 rating, tying for the highest customer score in this guide. It is explicitly described as a GM-recommended replacement for the original factory locking fuel cap, giving buyers a clear advantage when their vehicle is a compatible GM model.
Pros
- GM-recommended replacement
- Built to GM OE specifications
- Strong 4.4 customer rating
- Quarter-turn operation is straightforward
Cons
- Primarily intended for GM vehicles
- No broad cross-brand fit list
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Its primary job is to create a tight seal around the fuel tank opening while adding a lock intended to deter fuel theft. The quarter-turn format offers a familiar locking action, and two keys are included. The product is manufactured to GM original-equipment specifications for fit, form, and function and is stated to meet or exceed strict quality requirements.
Unlike the broad aftermarket listings, this option does not advertise a long multi-brand compatibility list. That is not necessarily a disadvantage; a focused original-equipment product can provide more confidence for the exact vehicle platform it was designed to serve. Buyers should confirm GT264 and the related number 25862765 against their original cap and vehicle requirements before ordering.
For a compatible GM owner, this is the most balanced recommendation in the guide. It combines a strong rating, clear brand provenance, an included key pair, and an emphasis on manufacturing standards. It is less suitable for someone who needs a cross-brand or classic-vehicle cap, but for a correctly matched GM application it provides excellent confidence in fit and function.
Original-Equipment Confidence
A GM-recommended component with OEM manufacturing standards offers a clearer quality and fit proposition than a generic universal substitute. The part remains vehicle-specific, so confirming the replacement identifier is essential.
Secure and Simple Quarter-Turn Action
The quarter-turn lock combines quick daily operation with theft deterrence. A complete turn into the locked position should engage the mechanism, while two keys offer a backup if one is misplaced.
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7. Gates 31828 – Rugged Heavy-Duty Sealing
Gates 31828
Heavy-duty rugged construction
Two included keys
Quarter-turn key operation
Fuel-resistant rubber seals
The Gates 31828 has a 4.2 rating and stands out for rugged construction, fuel-resistant seals, and a quick quarter-turn key action. It is a focused replacement for vehicles requiring a regular locking fuel cap in the 2-29/32-inch emission-control size, with a quick-on dimension of 1-25/32 inches by 2-15/32 inches.
Pros
- Strong 4.2 customer rating
- Heavy-duty construction
- Fuel-resistant rubber seals
- One-quarter-turn lock operation
Cons
- Specific dimensional fitment required
- No broad vehicle list provided
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The supplied specifications state that the cap uses seals compounded from fuel-resistant rubber. This is particularly relevant because the cap is constantly exposed to fuel vapor, changing temperatures, road debris, and repeated handling. The locking mechanism is designed to deter theft and vandalism, while the included pair of keys adds convenience and recovery from a single lost key.
The main limitation is that the listing offers dimensions rather than a broad vehicle compatibility chart. Those measurements are useful, but buyers must also consider thread type, sealing depth, venting, and cam profile. The heavy-duty description is supported by the product’s construction language, though it should not be taken to mean every cap fits every heavy-duty truck.
This is an excellent option for a buyer who can match the 31828 number or listed dimensions and values durable sealing. It is particularly appropriate for work-oriented vehicles, trucks, and SUVs where frequent servicing and weather exposure make robust construction valuable. Confirm the original cap’s measurements and locking style before purchase.
Fuel-Resistant Rubber Sealing
Fuel-resistant rubber helps the cap maintain a dependable barrier against vapor leakage. Inspect the seal for cracking, flattening, or deformation when replacing an older cap, and clean the filler neck before installation.
Built for Regular Service
Rugged heavy-duty construction suits vehicles that see frequent use and broad weather exposure. The quarter-turn lock also allows a quick visual check that the cap has reached its secured position.
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8. Keyed Alike Locking Fuel Cap – Convenient Shared-Key Design
Keyed Alike Locking Fuel Cap
Keyed-alike lock design
Durable long-life materials
Independently emission-control tested
Theft and vandalism deterrence
The Keyed Alike Locking Fuel Cap has a 4.3 rating, giving it one of the strongest customer scores among the alternatives. Its defining feature is a keyed-alike lock, a design approach commonly used where the goal is convenient access through a shared key format rather than a uniquely keyed cap.
Pros
- Convenient keyed-alike concept
- Solid 4.3 customer rating
- Emission-control testing noted
- Durable material construction
Cons
- Detailed dimensions not supplied
- Fitment requires additional verification
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The cap is manufactured from durable, long-life materials and is described as independently tested for emission control. Its lock protects the fuel from theft and vandalism, while the emissions-related testing addresses a separate and important concern: a replacement cap must seal correctly and work with the vehicle’s fuel vapor system rather than merely turn and lock.
The supplied product information is concise and does not include a detailed vehicle list, dimensions, thread specification, or sealing type. Those omissions make verification especially important. A buyer should compare the existing cap and its part number against the manufacturer’s fitment information before purchase. The keyed-alike description should also be understood in context; buyers should confirm whether they are seeking a new key pattern or compatibility with an existing keyed-alike system.
This is a compelling choice for drivers who value a straightforward keyed cap, durable materials, and emission-control testing. Its 4.3 rating supports a favorable recommendation, but fitment information should determine the final decision. If your vehicle requires a specific dimensional or original-equipment cap profile, choose this only after confirming that the seller provides a matching application.
Convenient Key Coordination
A keyed-alike format can simplify key management when it corresponds with the lock system already used on the vehicle or a related accessory. Verify the intended key pattern before installation because this designation alone does not establish complete vehicle compatibility.
Emissions-System Awareness
Independent emission-control testing is a meaningful differentiator because fuel caps are part of the vehicle’s vapor-management system. A properly fitted cap helps preserve the intended sealing and emissions performance.
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9. Gates 31670 – Deep-Cam Rugged Fuel Cap
Gates 31670
Heavy-duty rugged construction
Two included keys
Quarter-turn key operation
Fuel-resistant rubber seals
The Gates 31670 has a 4.0 rating and provides a locking option built around fuel-resistant rubber seals, rugged construction, and quick key operation. It is listed as a regular locking fuel cap in the 2-5/8-inch emission-control size, with a deep-cam configuration measuring 1-3/8 inches by 1-7/8 inches.
Pros
- Well-regarded customer rating
- Heavy-duty construction
- Fuel-resistant rubber seal
- Two keys included
Cons
- Deep-cam fitment must match
- Limited published application detail
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The deep-cam profile is the defining specification. It indicates that the cap is intended to engage a particular style and depth of locking mechanism, which makes this model a candidate for owners who know their vehicle uses that cam format. The lock opens with a quarter turn of the key, and two keys are supplied to provide some protection against lockout.
As with the Gates 31828, the listing relies more heavily on measurements than a long vehicle compatibility list. The cap is said to deter fuel theft and vandalism, and the rubber seals are compounded for resistance to fuel. Its rating is positive, though not as high as the GM Genuine Parts GT264 or Keyed Alike Locking Fuel Cap. The supplied information does not describe particular customer complaints.
Choose the 31670 if the existing cap’s size and deep-cam design match the listed specifications. It is a sound choice for a driver who wants a recognizable heavy-duty replacement with reliable sealing and two keys. Buyers should not select it solely because the vehicle is a truck or SUV; the cam profile, thread, diameter, and venting arrangement are more important than a general vehicle category.
Deep-Cam Compatibility Matters
The stated 1-3/8-inch by 1-7/8-inch deep-cam dimensions are the most useful identifiers for this model. Compare them with the original locking mechanism rather than estimating from the filler-neck opening.
Durable Sealing for Daily Use
Fuel-resistant rubber and rugged construction support dependable daily operation. A clean sealing surface, undamaged gasket, and correct tightening are essential for maintaining the advertised protection.
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10. Locking Gas Cap for Chrysler – Broad Stellantis Compatibility
Locking Gas Cap for Chrysler
Replaces two factory numbers
Jeep and Dodge compatibility
Chrysler and Ram applications
Four-wheel-drive model coverage
This locking gas cap carries a 4.4 rating and is tailored to an extensive range of Jeep, Dodge, Chrysler, and Ram vehicles. It replaces part numbers 05278655AB and 5278655AB, giving owners two common identifiers to compare with the original cap before making a purchase.
Pros
- High 4.4 customer rating
- Extensive Stellantis model list
- Clear replacement identifiers
- Covers popular Jeep and Ram trucks
Cons
- Vehicle-specific fitment still required
- No detailed seal specifications
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The listed Jeep applications include Wrangler, Grand Cherokee, Commander, Patriot, Liberty, Cherokee, and Compass models. Dodge coverage includes Ram trucks, Dart, Journey, Grand Caravan, Neon, Stratus, Dakota, Durango, Magnum, Charger, Challenger, Avenger, and Caravan applications. Chrysler models include 300, Pacifica, 300M, Aspen, PT Cruiser, Town and Country, and Sebring, with additional Ram truck and ProMaster coverage.
The breadth of the application list is useful for owners of common Stellantis platforms, but the long list should still be treated as a starting point for fitment. Fuel filler interfaces can vary by production date, market, fuel system, and trim. The provided information does not describe the seal material, lock operation, dimensions, or venting design, so a physical comparison is advisable before purchase.
This cap is a strong recommendation for a compatible Jeep, Dodge, Chrysler, or Ram owner who values an established 4.4 customer rating and a clearly identified replacement part. It is particularly relevant to popular Wrangler, Grand Cherokee, Charger, Challenger, and Ram applications. Confirm the part number, filler-neck thread, cap diameter, and any emissions-system requirements before installation.
Coverage Across Major Stellantis Brands
The fitment list spans Jeep, Dodge, Chrysler, and Ram, providing a useful reference across several brands that often share fuel-system components. Match the year, model, and original part number before ordering.
Popular Truck and SUV Support
Extensive coverage for Wrangler, Grand Cherokee, Ram, Charger, and Challenger applications makes this a practical option for owners seeking theft deterrence on high-use vehicles. Verify that the vehicle does not require a diesel-specific or otherwise distinct cap.
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Buying Guide – How to Choose the Best Locking Gas Cap with Keys
Choosing a replacement locking fuel cap involves balancing exact fit, sealing performance, lock security, durability, and key availability. Because a fuel cap is a safety-related emissions component, compatibility should be established before appearance, broad marketing claims, or convenience features.
Vehicle and Part-Number Compatibility
Begin with the part number molded, stamped, or printed on the existing cap. The most reliable listings identify the numbers they replace, and the strongest match is a direct replacement for the same vehicle platform and production period. Do not rely only on a vehicle’s make and model because a manufacturer may use different fuel caps across trims, model years, tank configurations, and markets. For example, several products in this guide replace 10504, 31780, or 77300-47020, while the Stellantis-focused cap references 05278655AB and 5278655AB, and the GM Genuine Parts option lists GT264 and 25862765.
Confirm the listed year ranges, then compare the old and new caps. Look for matching thread size, flange shape, diameter, height, cam style, venting, and locking mechanism. If the seller provides a detailed fitment guide, consult it, and when in doubt ask the seller or a qualified parts professional before ordering. A visually similar cap can still be unsafe or incompatible.
Sealing and Emissions Compatibility
A fuel cap must close the filler neck securely to help manage vapor, resist contamination, and maintain the vehicle’s fuel system. Look for a fuel-resistant rubber seal, a flat and undamaged sealing surface, and a design that provides proper compression when tightened. Some listings specifically mention low fuel permeability, leak resistance, emission control, or independent emissions testing. These details are more relevant than a generic claim that a cap is waterproof because the cap and seal perform different jobs.
Check whether the vehicle requires a vented, non-vented, or emissions-certified cap. A vented cap contains a controlled path for fuel vapor, while a non-vented cap is intended to work with a system that manages vapor elsewhere. An incorrect configuration can produce a persistent fuel odor, a diagnostic warning, or an evaporation-system fault. Do not alter a supplied cap or improvise a sealing solution.
Lock Mechanism and Key Security
A keyed lock is primarily a theft deterrent rather than an absolute guarantee that fuel cannot be removed. Mechanical cylinders are simple, dependable, and require no battery, but a determined thief may still attempt to damage the cap. The best options use an integrated or well-fitted lock cylinder and include a straightforward locked position. Quarter-turn operation is convenient for frequent refueling, and keyed-alike designs can simplify key management when the key pattern is confirmed in advance.
Consider how many keys are supplied. Two keys offer a practical backup if one is lost, damaged, or locked inside the vehicle, but one should be stored securely outside the vehicle. Do not assume that a replacement cap comes with keys matching every other lock on the car. The cap’s key pattern and the number of supplied keys should be confirmed before purchase.
Materials and Environmental Durability
ABS plastic is common in aftermarket fuel caps because it combines a light weight with useful hardness and toughness. Metal caps offer a heavier, more decorative construction that can suit restoration and custom applications. Whatever the material, the important qualities are resistance to gasoline, chemical exposure, cracking, warping, corrosion, and temperature changes. The United Pacific S1301 stands apart with an all-metal body and triple-chrome finish, while several alternatives use ABS plastic with rubber sealing rings.
A fuel cap is exposed to sun, rain, road salt, fuel, hand oils, and repeated twisting. Look for a smooth locking action and a seal that does not appear hardened, split, or permanently compressed. Inspect the cap periodically and replace it if the threads crack, the key becomes stiff, or the cap no longer seats firmly. Quality control matters because a small defect can undermine an otherwise proper installation.
Ventilation and Locking Style
The correct locking style is determined by the vehicle’s original filler-neck interface. Some caps use a regular or deep cam, while others are designed for quick-on or specialized locking mechanisms. The Gates 31828 is identified as a regular locking cap with listed quick-on dimensions, and the Gates 31670 is described as a deep-cam regular locking cap. Those distinctions are more precise than broad claims that a product fits many vehicles.
Older classic vehicles may require a vented cap, making the United Pacific S1301 relevant to specific Chevrolet and Ford applications. Modern vehicles may instead have a vented or emissions-style cap with more exact requirements. Compare the old cap’s underside, receiver, and cam profile with the replacement. If there is any uncertainty, do not force the cap into place or use an adapter that was not designed for that vehicle.
Installation Ease and Included Hardware
Most of the plastic replacement caps in this guide install without special tools. The typical process is to remove the old cap, clean the filler neck, align the threads, and turn clockwise until seated or a click is heard. A quarter-turn locking cap may have a slightly different final motion, so follow the markings on the cap and the seller’s instructions. A click can indicate proper engagement, but it should not replace a visual check of the seal and lock position.
Check whether the package includes the complete cap, integrated seal, lock cylinder, and keys. United Pacific specifically notes that its order contains one cap and two keys, while most of the replacement caps also list a pair of keys. The Keyed Alike Locking Fuel Cap has a concise description and does not state a key count in the supplied information, so ask about included keys if that is essential. Never assume the old key will operate a new lock.
Brand Provenance and Quality Confidence
An original-equipment or established branded product can be attractive when its vehicle application is confirmed. The GM Genuine Parts GT264 is described as a GM-recommended replacement manufactured to original-equipment specifications, while the Gates caps emphasize heavy-duty construction and fuel-resistant seals. Generic aftermarket caps may offer broader model coverage and lower cost, but their fitment lists often require more careful interpretation.
Customer ratings provide a useful but incomplete quality signal. The GM cap and Stellantis-focused locking gas cap both have 4.4 ratings, while Gates 31828 has 4.2 and the Keyed Alike option has 4.3. Lower-rated products may still be the correct answer for a specific vehicle, and high ratings cannot compensate for incorrect compatibility. Use ratings alongside part numbers, physical dimensions, materials, and seller support.
How to Use and Care for Your Locking Gas Cap
Before replacing a cap, park the vehicle on level ground, allow the engine to cool, and identify the original part number. Compare the replacement with the old cap for thread size, diameter, depth, vent style, and cam shape. Clean the filler-neck opening and remove dirt, ice, grit, old sealant, or residue that could interfere with the seal.
Install the cap by hand initially to avoid cross-threading. Align the threads straight with the filler neck and turn clockwise only as far as the cap or seller instructions indicate. For a quarter-turn or click-style cap, move the key to the locked position and remove it. Do not use excessive force; resistance can indicate a mismatch or a misaligned thread. Confirm that the cap sits level and the lock cannot be opened without the proper key.
During routine use, check the cap for looseness, a fuel odor, condensation, or visible damage. Clean the exterior with a damp cloth and mild cleaner, keeping liquid out of the filler neck. Inspect the rubber seal for cracks or flattening, lubricate only with a product approved for fuel-system seals if the manufacturer permits it, and replace the cap if the key becomes stiff or the locking mechanism no longer holds securely.
Frequently Asked Questions
How do I know which locking gas cap will fit my vehicle?
Start with the part number on the original cap and compare it with the replacement numbers listed by the seller. Then verify the vehicle’s make, model, year, and fuel type against the published fitment information. A physical comparison of thread size, diameter, depth, venting, and locking cam provides a second check. Never rely on appearance or a general brand compatibility list alone.
Are locking gas caps worth installing for theft deterrence?
A keyed cap can deter casual attempts to remove the fuel cap, which may be valuable in areas where fuel theft or vandalism occurs. It cannot guarantee that a determined thief will not damage or remove the cap. Correct fitting and a functioning lock are essential; a loose, incorrect, or damaged cap can create fuel-system and emissions problems.
Will the keys from my old gas cap work in a replacement?
Not always. A replacement may use the same key pattern, a different pattern, or a keyed-alike system for multiple applications. The product information should state whether keys are included and whether the lock is keyed alike. Test the included key before relying on it and keep a backup in a secure location outside the vehicle.
Can I use a locking gas cap from a different vehicle?
Only when the part number and physical interface match. Fuel caps can differ in thread pitch, flange design, depth, vent configuration, and locking cam even when the caps look nearly identical. Forced installation can lead to poor sealing, fuel odor, evaporation faults, or damage to the filler neck. Verify compatibility before removing a working original cap.
What should I do if the cap clicks before it feels tight?
A click can be part of the normal locking mechanism, but you should still confirm that the cap is level, fully seated, and locked. If it remains loose, binds, or requires force, stop and remove it. Recheck the part number and compare the threads and cam with the original cap rather than continuing to tighten a potentially incompatible component.
Is a vented locking gas cap better than a non-vented model?
Neither is universally better; the vehicle’s fuel-vapor system determines the correct choice. A vented cap is intended for a filler neck or fuel system designed around that venting path, while a non-vented cap may be required when vapor is managed elsewhere. Matching the original design and emissions requirements is essential.
How often should a locking fuel cap be inspected?
Check it during routine vehicle maintenance and whenever you notice a fuel odor, a warning light, a loose cap, or difficulty turning the key. Inspect the seal for splitting, hardening, flattening, or tears, and confirm that the cap seats evenly. Replace it if the locking mechanism, threads, or sealing surface no longer function properly.
Does a locking gas cap affect the vehicle warranty?
A compatible replacement that functions correctly should not create a warranty issue, but an improper or defective cap can cause leaks, odors, evaporative-system faults, or fuel-system damage. OEM-branded and manufacturer-recommended replacements can offer added confidence. Keep your receipt and installation records, and use a qualified technician if fitment is uncertain.
Final Thoughts on Choosing the Best Locking Gas Cap with Keys
The GM Genuine Parts GT264 is the strongest all-around recommendation for a compatible GM driver because of its 4.4 rating, two keys, original-equipment positioning, and quarter-turn locking design. The Locking Gas Cap W/2 Keys is the best budget-oriented choice for a vehicle that matches its common replacement numbers and broad Toyota applications, while the United Pacific S1301 is the premium option for older Chevy and Ford restorations that require a vented, chrome-finished metal cap.
Fitment should remain the priority regardless of brand, material, or rating. Verify the original part number, model year, thread, diameter, depth, cam style, venting, and fuel type before buying. For owners who can match precise dimensions, the Gates 31828 and Gates 31670 offer rugged construction, fuel-resistant seals, two keys, and a quick quarter-turn lock. The Stellantis-focused option is especially relevant for compatible Jeep, Dodge, Chrysler, and Ram vehicles.
Current prices and product availability can change, so compare the latest listing, customer feedback, seller information, and full fitment details before making a final purchase. Also confirm how many keys are included and keep a spare outside the vehicle. A properly matched locking cap can add useful theft deterrence while preserving the sealing function your vehicle’s fuel system expects.