The gas cap is one part of your vehicle that we bet you don’t give much thought to in spite of how often you use it. The thing is, a gas cap does a lot more than simply close off your vehicle’s filler neck when you’re done gassing up. Your vehicle’s gas cap is part of a complex emissions control system that helps prevent pollution that can cause environmental harm. Specifically, the gas cap seals your car or truck’s gas tank against escaping gasoline vapors.

You know that clicking sound the gas cap makes when you turn it clockwise to close the tank? That’s the sound of the cap’s seal engaging; if your vehicle’s current gas cap doesn’t make that sound, it could be one of the first clues that it has failed—or is about to. There are other signs to watch for too, one of which is the illumination of the “check engine” light. Often an ominous indicator of a future expensive repair, your car’s manufacturer also uses it to tell you your old gas cap has given up.

Thankfully, replacing your vehicle’s gas cap is not expensive. For proof of that, read on for our recommendations for the best gas caps you can buy, whether you need to replace one that’s failing, or you simply forgot your original at the gas station one day and drove off.

For more information on the best gas caps, refer to our table of contents.

1. Editor’s Pick: Gates Fuel Tank Cap (31838)

Gates 31838 replacement gas cap for Jeep and Chrysler vehicles

Gates is a big name in the aftermarket auto parts industry, a level of success the company has achieved by making parts for a wide range of popular vehicles. Among them is this replacement gas cap (31838), which is a direct-fit part you can buy for Chrysler, Dodge, and Jeep models, as well as some Nissan, Mitsubishi, and Subaru cars and SUVs.

Gates says you can use this gas cap regardless of whether your vehicle has a shallow or deep fuel filler neck with or without venting. However, Gates says this cap is meant only for gasoline-fueled vehicles, so if you drive one of the Jeep or Dodge SUV or truck models available with a diesel engine, you may have to look for a different replacement fuel cap.

Gates offers this gas cap in durable plastic, and in a metal version for vehicles with an exterior-mounted cap. If your vehicle has a tether for the gas cap, you can attach it to this replacement part.

2. Best for Older GM Vehicles: ACDelco GM OE Fuel Tank Cap (GT261)

Best Replacement Gas Cap for Older GM Vehicles: AC Delco GT 261

General Motors has a long reach in the auto industry, having owned and operated a large number of sub-brands. Despite the variety in the GM vehicle portfolio, there is a lot of parts commonality between vehicles that, on the surface, are much different. That is how you end up with a replacement gas cap that fits more than 700 different GM vehicles (if you count different model years) built from the late 1990s through to the mid-2000s.

ACDelco specializes in replacement parts for General Motors vehicles, which means they know how your car works almost as well as GM does. The ACDelco GT261 is a standard-type, threaded plastic gas cap that lives underneath your vehicle’s gas door. It has a rubber gasket to seal your fuel filler neck against water and dust, and a check valve to control air pressure in your gas tank and limit the flow of fuel vapors.

To give you an idea of the range of vehicles the ACDelco GT261 fits, they include Oldsmobile, Buick, Chevrolet, and Pontiac models with common four-cylinder, V6, and V8 engines. We only recommend this gas cap for vehicles with gas (black cap) and flex-fuel (yellow cap) engines. Diesel-equipped trucks require a different cap design.

3. Best for Older European Cars: MotoRad Tethered Fuel Cap (MGC-817T)

Best Replacement Gas Cap for Older European Cars: MotoRad MGC817T

One of the frustrating aspects of driving an aging European car can be the challenge of finding replacement parts. If you frequently find yourself in that situation, this MotoRad gas cap may be what you need. The company says this cap is designed as a replacement for vehicles made by almost every manufacturer in business in North America today, as well as some brands that long ago disappeared from this continent. Among those now-defunct automakers are Daewoo, Daihatsu, Lancia, Renault, and Suzuki.

And if you drive a vintage Volvo 240 or the now-rarely seen Volkswagen Fox, this gas cap should solve your emissions control system issues. It is also specified for a variety of 1970s and 1980s General Motors vehicles, along with older Jeep and Land Rover off-road models.

This non-locking gas cap does include a tether—a rare perk in a replacement part—which means you won’t have to transfer the one from your old gas cap. MotoRad says that if you buy this gas cap and it is faulty, the company will replace it free of charge or refund your money.

4. Stant Fuel Cap (10817)

Stant 10817 Replacement Gas Cap

Here’s another replacement gas cap we recommend if you drive an older vehicle, whether from an import brand or one built in North America. The Stant 10817 is a straightforward replacement cap that does not come with a tether. Despite that omission, this is a well-reviewed gas cap that should serve you well as an inexpensive solution for the warning light on your vehicle’s dashboard or if you accidentally misplaced your factory cap.

This non-locking gas cap is made of textured black plastic that is common for this part. Though it is designed as a direct-fit replacement, this cap is a little smaller than the OEM part on some vehicles. If you have installed an aftermarket fuel door that interferes with your OEM gas cap, you may have better luck with this one.

If you drive a Porsche 924, an older Volvo or VW, or a vehicle from defunct brands like Saab, Suzuki, or Renault, there is a good chance this cap with fit your fuel filler neck.

5. Gates Gas Cap (31832)

Gates 31832 Gas Cap for Honda and GM Vehicles

Here’s a recommendation from the aftermarket pros at Gates, which is a direct-fit replacement primarily for GM and Honda models. This gas cap is vented to meet the requirements of vehicles prone to vacuum build-up in the fuel tank that can cause a poor-running engine. Like most modern gas caps, this one clicks when you turn it to indicate that your gas tank is properly sealed.

Among the fitments Gates recommends for this gas cap are the Cadillac CTS luxury sedan, the Chevrolet Malibu and Honda Accord family cars, the Lexus RX 350 upscale SUV, Chevrolet’s Volt plug-in hybrid, the Toyota Avalon and Camry sedans, and the Honda Insight and Toyota Prius hybrid cars. Other vehicles to which buyers successfully fitted this gas cap are the Honda CR-V and Element SUVs, Subaru’s Forester crossover, and even the Subaru STI sporty car.

It’s worth mentioning that Gates says this cap may arrive in Delphi packaging due to manufacturing partnerships that it has with other aftermarket suppliers.

6. Best for Jeep Off-Roaders: Allmotorparts Gas Cap (AMP140)

 Best Replacement Gas Cap for Jeep Off-Roaders: AllMotorParts AMP140

If you drive a Jeep Wrangler off-road SUV, Allmotorparts makes a replacement gas cap designed to be a perfect fit for your vehicle. This gas cap is tethered to help prevent the loss of a cap you’ve placed on your vehicle’s roof while refilling. However, it is not lockable.

Most buyers report that this replacement part looks identical to the one that came with their vehicles. If maintaining a fully OEM appearance is important to you, this gas cap puts you on the right track.

Jeep has been building the Wrangler for many years and has redesigned this vehicle several times. However, Allmotorparts’ gas cap fits a wide range of model years. If you drive the Wrangler TJ sold from 2003 through 2007, this cap gets along with the emissions control system attached to the four- and inline-six-cylinder engines under your hood. It also works with the 3.6- and 3.8-liter V6s in the JK generation of 2007-2017. However, if you drive the JL generation introduced in 2018, this cap is not compatible.

7. Best Locking Gas Cap: Gates Locking Fuel Tank Cap (31778)

Best Locking Replacement Gas Cap: Gates 31778

If your primary concern is protecting yourself against fuel theft, here is another Gates replacement gas cap you can consider. The Gates 31778 is a locking gas cap for diesel and gasoline vehicles that locks and unlocks with a quarter-turn of the key. Your purchase includes two keys, so you can put one away as a spare, or put it on another driver’s keychain.

Gates says its 31778 gas cap has a two-way valve that helps relieve tank pressure and vacuum to avoid engine performance problems. It also seals in diesel and gas fumes to prevent the evaporative emissions that cause environmental pollution. If you purchase the diesel version of this cap, you will get a green one, while the model designed for gasoline cars is black.

Gates says this fuel gap fits a rather eclectic set of vehicles. It’s primarily designed for Ford and General Motors heavy-duty trucks and vans, but also fits some Toyota Camry and pickup truck models, and Volvo 200- and 700-series cars.

8. Best for BMW and MINI: ROVIKE Gas Cap

Rovike Replacement Gas Cap for Mini and BMW Vehicles

If you drive a BMW or MINI high-performance car or crossover, here’s an affordable direct fit replacement from ROVIKE. Among this gas cap’s unique features is the nipple on the underside, which is designed to fit a hole on the inside of the fuel door. That’s BMW’s solution for preventing a dangling gas cap from damaging the bodywork around your vehicle’s fuel filler. However, this cap does also come with a tether to keep it attached to the car.

ROVIKE says this gas cap fits most BMW and MINI models from the early 2000s through to 2018. Those cars include the Cooper, Clubman, and Countryman hatchbacks and SUVs, as well as virtually every BMW model line from that period.

That covers a number of different engines and emissions control systems: The MINI models use 1.6-liter turbocharged and naturally aspirated engines, while applicable BMW models may have turbocharged 2.0-liter four-cylinder engines, six-cylinder engines with and without turbocharging, and high-end performance luxury models with turbocharged V8 and V12 powertrains.

More importantly, this aftermarket gas cap is noticeably more affordable than BMW’s OEM replacement part.

9. Best for Toyota and Lexus: YCT Gas Cap (YCT1406)

 Best Replacement Gas Cap for Toyota and Lexus Models: YCT Auto YCT1406

If you drive a Toyota, you don’t need us to remind you that this Japanese brand is renowned for building ultra-reliable, long-lasting vehicles. YCT makes this replacement gas cap to fit virtually every vehicle Toyota and its upscale Lexus brand made between 2005 through 2015.

Like the vehicles it’s meant to fit, this gas cap appears to be a well-made product at a reasonable price. The design is quite conventional and bears the same warnings as the OEM gas cap: one against using fuel with more than 10-percent ethanol content, and another alerting you to tighten the cap to avoid turning on the “check engine” light. It also comes with a tether to help you avoid losing the cap after filling your vehicle’s tank.

This gas cap fits a long list of vehicles with different engines and emissions control systems. Those include the 1.8-liter four-cylinder in Corolla sedans and Matrix hatchbacks, Camry family cars with four-cylinder or V6 engines, RAV4, 4Runner, and Highlander SUVs, and 1.5-liter Yaris hatchbacks. If you’re a Lexus driver, this cap will fit the IS and ES sedans, the LS full-size luxury car, and the brand’s GX, RX, and LX SUV models.

10. Best for GM Trucks and SUVs: POWERWORKS Gas Cap (GT330)

Best Replacement Gas Cap for GM Trucks and SUVs: Powerworks GT330

POWERWORKS makes this gas cap as a replacement part for General Motors crossover, SUV, and pickup truck models built between the mid-2000s and early 2010s. The company is upfront about the fact that this is a replacement part and not a genuine OEM product. Still, this direct-fit piece should perfectly fit your vehicle’s fuel filler neck; it also includes a tether so that it remains attached to the vehicle at all times.

POWERWORKS says it makes the GT330 gas cap of resin plastic that is resistant to high and low temperatures. It also has a fluororubber o-ring to create a reliable seal between the cap and your truck’s filler neck. The company promises a three- to five-year service life.

Priced competitively, this is an affordable way to get your GM truck running properly again. POWERWORKS’ fitment list includes the 3.6-liter V6 engine in the Buick Enclave, Chevrolet Traverse, GMC Acadia, and Saturn Outlook crossovers from 2007 through 2011. It also fits V8-powered Chevrolet and GMC full-size SUV and pickup models sold from 2004 to 2011.

How can you tell when you need to replace your gas cap?

Photo credit: Zeljko Radojko/ Shutterstock.com

In modern cars, the gas cap is part of the vehicle’s evaporative emissions control system. The cap helps seal your car’s fuel system so that gasoline or diesel vapors don’t escape into the environment where they can contribute to climate change.

If your gas cap fails, you may notice a smell of fuel when you are near the vehicle. The cap may also not click when you tighten it. Finally, the failed gas cap can trigger your vehicle’s “check engine” warning light, which indicates—among other things—when there is a fault with the emissions control system. Some cars may have a dedicated warning light to tell you when the gas cap has failed, or that you didn’t tighten it fully the last time you fueled up.

If you suspect your gas cap may be faulty, you can get it tested at many repair shops that do vehicle smog tests. They will remove the gas cap from the car and attach it to a device that tests whether the cap provides an adequate seal. If it fails that test, you will have to replace the cap, but as you can see from this list of the best replacement caps, it is an inexpensive part.

Should you buy a locking gas cap?

If you are concerned about the possibility of fuel theft, then the obvious answer is yes. However, note that if your vehicle’s gas cap is hidden behind a fuel door that can only be released from inside the car, then a locking cap is probably unnecessary. If you drive a later model vehicle, that fuel door may lock and unlock along with the doors and trunk.

That fuel door is not a guarantee against fuel theft, but it will discourage thieves looking for an easy way to siphon gasoline from parked vehicles. That said, if a thief does pry open a latched fuel door only to find a locked gas cap underneath, they will be more likely to give up and move on to another vehicle.

Why are some gas caps green or yellow?

On most vehicles, the gas cap will be black to indicate that it is designed to run on gasoline with less than 10-percent ethanol content. If your vehicle has a green fuel cap, that means it runs on diesel. You’ll find a yellow cap under the fuel door if your car or truck needs gasoline with anywhere from 15- to 85-percent ethanol content.


We are committed to finding, researching, and recommending the best products. We earn commissions from purchases you make using the retail links in our product reviews. Learn more about how this works.

Photo credit: Zeljko Radojko / Shutterstock.com