10 Best Locking Gas Cap In 2020 Reviews & Buyer’s Guide

Ever noticed how the gas spills out of the car in Grand Theft Auto, and you have to make a run for it? And the next thing you know, BOOM!

Well, even though this happens in movies and games, you can’t say this won’t happen to you in real life as well, yeah? Besides, you’ll always see goons trying to steal gas from your car if you don’t use a locking gas cap.

Well, today’s the day you’re getting your hands on the best locking gas cap, mate. So, cheer yourself up and read the reviews. We’re talking about the top 10

Gates 31838 Fuel Tank Cap
ACDelco 12F20L Professional Locking Fuel...
Stant 10508 Locking Fuel Cap
Stant 10504 Locking Fuel Cap
Stant 10524 Locking Fuel Cap
Gates 31838 Fuel Tank Cap
ACDelco 12F20L Professional Locking Fuel...
Stant 10508 Locking Fuel Cap
Stant 10504 Locking Fuel Cap
Stant 10524 Locking Fuel Cap
3,644 Reviews
1,504 Reviews
1,077 Reviews
989 Reviews
893 Reviews
Gates 31838 Fuel Tank Cap
Gates 31838 Fuel Tank Cap
3,644 Reviews
ACDelco 12F20L Professional Locking Fuel...
ACDelco 12F20L Professional Locking Fuel...
1,504 Reviews
Stant 10508 Locking Fuel Cap
Stant 10508 Locking Fuel Cap
1,077 Reviews
Stant 10504 Locking Fuel Cap
Stant 10504 Locking Fuel Cap
989 Reviews
Stant 10524 Locking Fuel Cap
Stant 10524 Locking Fuel Cap
893 Reviews

After going through piles of research and getting through to the authentic users of fuel cap, we have outlined the top products for you. Therefore, dive into this review and get yourself the locking gas cap you need.

1. Gates Fuel Tank Cap

Highlighted Features

  • Heavy-duty construction
  • Two-way action
  • Fuel resistant rubber seal
  • Meets OEM specifications

Are you on a quest to get the best locking fuel cap? Then try out the 31838 tank cap from Gates, which is eagerly waiting on top of the market to get on your car tank.

It comes with an easy-going lock system. Simply rotate it past 3 clicks, and this cap is locked nice and tight to prevent vandalization of the fuel. Therefore, whenever you are not by the side of your darling car, this cap will deter thieves rigorously.

Plus, owing to being made of rugged plastic, it has a very heavy-duty construction. As a result, it will back your fuel tank up for a long time regardless of weather and environment.

Moreover, the 31838 from Gates works as a pressure/vacuum relief valve (PVRV), performing two-way action at once. This is also known as the "breather valve." So, the fuel fumes cannot escape from the fuel tank, in spite of the proper flow of air inside.

Besides, this tank cap boasts a fuel resistant rubber seal which is dominant in automotive and aeronautical industries. Therefore, it can effectively resist itself from aggressive oil, fuel, and gas.

Furthermore, it proudly meets up with the OEM specification that is Original Equipment Manufacturer. So, it boasts the same impressive quality as to the prior fuel cap.


  • Easy to install
  • Very durable
  • Saves fuel
  • Resists oil, fuel, gas
  • Praiseworthy quality


  • Hard to unlock in freezing temp

2. ACDelco 12F20L Professional Fuel Tank Cap

Highlighted Features

  • Premium threaded cap
  • Theft-proof
  • Click locks
  • Two sets of keys
  • Heavy-duty

When the thieves are on the loose, don’t allow them to steal your gas. That being said, the Professional Fuel Tank Cap from ACDelco will substantially look after your fuel.

Besides, this premium threaded cap makes sure you get to seal your fuel tank tightly. As a result, nothing from outside can break into your vehicle's fuel tank.

Also, the ACDelco 12F20L will substantially prevent tweakers, thieves from stealing fuel from your car, thanks for being 100% theft-proof. You don’t need to tire yourself by kicking their butts.

Plus, you’ll find this locking gas cap for car a breeze to lock your fuel tank. Just rotate it 12 and 6 o'clock, and it clicks; yes, it’s that simple!

Don’t lose your heart if you lose a key as this tank cap provides two sets of keys. Insert the key and turn 9 to 3 o’clock to unlock. Boy oh boy, this one works like a piece of cake.

However, remember to take out the key after unlocking; otherwise, the cap will spin round and round rather than coming off.

Moreover, it has been manufactured, maintaining high grades and versatility. Thus, it fits and sits flawlessly on any model and shape of the automotive.


  • Secured seal
  • Saves fuel
  • Easy to lock and unlock
  • Effortless to install
  • Suitable for versatile automotive


  • Does not fit as good as the OEM cap

3. Stant 10508 Locking Fuel Cap

Highlighted Features

  • OEM materials
  • High-quality locking mechanism
  • OE Vacuum and Pressure relief
  • Lost Motion function

Do you know you lose about 22 gallons of gas per year just because of a leaking gas cap? Well, never again with the Stant 10508 Locking Cap.

Unlike other aftermarket caps, it has been constructed with quality OEM materials. As a result, you don’t need to worry about wearing out this fuel cap in a short period.

Plus, this fuel cap comes with a locking mechanism that ensures high security to deter theft and vandalism. So, you won’t get a sudden “low-fuel” surprise in the mid of a long road.

Besides, the Stant 10508 locking cap is equipped with OE pressure and vacuum relief valve. The pressure relief prevents vapors from escaping under the normal condition. 

Also, the vacuum relief helps to keep the air pressure normal in the fuel tank under the usual condition. These vapors can be on blaze with a single spark. Therefore, it will help to keep the gas emission at a normal level.

Moreover, the last thing on earth we expect is a car crash! This gas cap prides with the “Lost Motion” function to prevent the leak of gas by providing a strong seal under such an unfortunate hazard. So, stop worrying and have a safe drive.


  • Durable and sturdy
  • Efficiently saves fuel
  • Easy-going locking system
  • Ensures safety
  • Prevents emission


  • Not well designed
  • Complicated locking system

4. Stant 10504 Locking Fuel Cap

Highlighted Features

  • OEM constructed
  • Lost Motion function
  • Pressure/Vacuum relief valve
  • Secure locking system

Do you smell gas after filling up the fuel tank chock-full? If yes, then you are in grave need of the best locking gas cap. And what could be better than the Locking Fuel Cap from Stant?

It has been constructed with OEM materials to fearlessly face and withstand any tough weather conditions or the biggest abuses. Therefore, you won’t need to spend money on buying another one for a long time.

Plus, when car accident rates are on the loose, fuel vapors are partially responsible for making it worse. That’s why this universal locking gas cap boasts of the Lost Motion feature to prevent leakage under the aforesaid circumstances. So, both you and your fuel tanks are in safe hands.

Moreover, the fuel cap from Stant possesses the vacuum/pressure relief valves. As a result, vapors cannot just flow out or get into the fuel tank.

These valves also create a way for the vapors to pass through under abnormal situations. Not to mention, smog is caused due to dissolving vapors. Therefore, you are saving gas as well as nature at once.

Besides, you don’t want to look awkward at a gas station with a jammed fuel cap, right? That’s why this gas cap comes with a secure yet simple locking system. It works in a clockwise motion.


  • Very durable
  • Easy-going installation
  • Protects from leakage
  • Controls vapors emission
  • Easy to lock


  • Doesn’t come off easily in cold weather

5. Stant 10524 Locking Fuel Cap

Highlighted Features

  • High-quality key operated lock
  • Torque Override function
  • Breakaway groove
  • Quality OEM materials

Stop frowning upon thieves for stealing your vehicle's gas rather get yourself the Stant 10524 locking gas caps for cars. This will surely make a world of difference in your life.

With this cap on the fuel tank, your worries of fuel thieves and vandalism will fly away, thanks to the key-operated high-secured lock. It will also take less effort from you while locking and unlocking.

Plus, it boasts with a handy Torque Override function to notify you with an audible click sound. When you hear the sound, it means that the O-ring which seals the cap is compressed correctly. Therefore, no more gas leaking from now on.

What if you bumped into another car, and the fuel tank gets wrecked? The result is the leakage of fuel, which can turn out to be very dangerous. No worries, the Stant 10524 shows off Breakaway Groove to seal fuel under suchlike condition. So, it will back you up irrespective of time and event.

Moreover, for performing such big tasks cited above, it surely needs to be strong and durable enough. Well, that has been confirmed by building up this locking gas cap using quality OEM materials. As a result, this is unlike other aftermarket caps that will leave you so soon.


  • Easy to lock
  • Highly secured
  • Simple installation
  • Seals fuel actively
  • Very durable


  • Not suitable for most car models

6. Gates 31844 Locking Fuel Cap

Highlighted Features

  • Thermoplastic compound
  • Water-resistant feature
  • Optimum tightness
  • Resistant to wears and tears

From the maker of some of the most premium-quality fuel caps comes another top-quality product – the 31844 cap.

When it comes to the fuel cap, you can't mess it up with quality, can you? That's what producers at Gates thought. The 31844 is built from a durable premium-quality thermoplastic compound that ensures top-notch resistance and durability.

Don't worry if it soaks water during rainy rides or you are washing the machine. The gas cap is entirely water-resistant. Plus, the thermoplastic material works great in slowing down wear and tears. So, be sure that it will need the least maintenance you can plan for.

The cap seals the tank hole with optimum tightness that closes down all the ways of leakage and spillage. Even if there is a lot of jerking, no fuel is going to spill off through the cap.

On the plus side of this cap, it fixes securely in its place and allows zero tamperings with the fuel tank. Trust us, if you are looking for premium service from a gas cap at an affordable price, you better not think twice to own this one.

As for installing this on your fuel tank, it is one of the easiest of all. You don't need any fancy or complex tools for the installation. It takes only a few minutes to set up, and you are ready to go!


  • Easy to install
  • Protects the tank from any tampering
  • Allows zero leakage and spillage
  • Affordable


  • Once locked, it needs a bit of pressure to unlock it

7. Gates 31836 Fuel Tank Cap

Highlighted Features

  • High-quality construction
  • Twistable locking fuel cap
  • Two square keys
  • Two relief valves
  • Vastly compatible

Ok, you can’t figure out why your fuel meter shows “low-fuel” even after refueling? Let's clear it out; your existing fuel cap is at death’s door. And unless you get the best locking gas cap, it’s going to get worse. So, what can be better than Gates 31836 Fuel Tank Cap?

That being said, this gas tank cap ensures superior durability and endurance, thanks to the high-quality construction materials. So, it is going to stay by your side through thick and thin.

Plus, it doesn’t require much effort to lock on your vehicle's fuel tank. Just put it into the tank and twist moderately, and it's locked! See, locking has been made so easier with this cap.

Besides, you’ll be provided with two square keys so that if you lose or forget one key, you don’t need to call the mechanic to open the cap. They are also built with sturdy materials to digest daily abuses.

Moreover, this best gas cap boasts with two PVRV valves, also known as pressure/vacuum relief valve. Their task is to prevent the vapor from flowing outside while allowing airflow inside under normal conditions. Therefore, you can be sure that it will keep your car's internal mechanism smooth and working.

Furthermore, thanks to the Gates for manufacturing this fuel tank cap, it’s suitable for almost all models of cars. So, you don’t need to buy a couple of different caps from now on.


  • Very durable
  • Installation is simple
  • Locking is a breeze
  • Sturdy keys
  • Maintains the vapor recovery system


  • Some car shows engine light

8. MotoRad MGC907 Locking Fuel Cap

Highlighted Features

  • OEM-quality materials
  • Emission standard
  • Vacuum and Pressure relief valve
  • Dual functioning fuel cap

When aftermarket fuel caps leave you dead meat after few uses, the MGC907 from MotoRad steps in to revive you.

This fuel cap boasts with OEM materials to ensure that it doesn’t wear off with rigorous uses regardless of the weather. Therefore, no worries; it will go long enough to save big bucks for buying another MotoRad fuel cap for your car.

Plus, it has gone through every standard independent test to make sure that it can control the fuel emission efficiently by sealing the fuel tank properly. Go on and take the credit of a nature saving person.

Moreover, the MotoRad MGC907 comes with a helpful vacuum and pressure relief valve. They prevent fuel from evaporating, which can essentially save your fuel. So, from now on, fuel won't just vanish from the tank, thereby saving your money on refueling.

In addition to saving the money, it also prevents the flow of fuel from the filler through the neck under catastrophes like a rollover or crushed fuel tank.

Besides, this cap is easy-peasy to lock with a simple twist. But what makes it top-notch is that, when you move the key leftward and remove it, then it's unlocked but cannot spin freely. Therefore, this is probably the best locking gas cap, owing to its both locking or unlocking function to deter thieves.

Further, if you are a rider of multiple cars, then this one will become very handy. That’s because it has been manufactured to fit on Kia Optima, Hyundai Elantra, Dodge Durango, Chrysler Town & Country, Grand Caravan, Sonata, Jeep Grand, and so on.


  • Amazingly durable
  • Controls fuel evaporation
  • Ensures safety
  • Cost and fuel-efficient
  • Easy to lock
  • Fits various cars


  • Shows check engine alert on some cars
  • Inconsistent quality

9. Stant 10511 Locking Fuel Cap

Highlighted Features

  • Quality plastic
  • Specially designed valves
  • High-quality locking mechanism
  • Emissions-proof

So, you want to keep the gas in the tank with the best tank locks, right? Get your hands on the Stant 10511 locking fuel cap to meet your demand.

It is made of high-quality plastic materials provided by an authentic OE supplier to make it strong enough for weathering the storm. Thus, you can have peace of mind accepting that a durable and sturdy fuel cap is protecting the tank.

Plus, this fuel cap boasts with two specially designed valves that prevent vapor flow while allowing the entry of air. So, from this moment forth, costly fuel won’t just vanish into the air.

Moreover, you are well familiar with thieves who are always on to steal fuel. Well, lock the tank filler with this cap, and it will make sure that no tweakers can walk away with fuel, thanks to the high-quality locking mechanism.

In addition to providing high security, it takes less effort to lock the fuel tank. Just put the cap on and tighten it.

Besides, you’ll be glad to know that it performs a mindboggling job of preventing fuel emission, which ultimately reduces the amount of hydrocarbon in the air. Therefore, you are not only getting the best of both worlds but also protecting the world.


  • Long-lasting fuel cap
  • Prevents evaporation
  • Protects from vandalism
  • Easy to lock
  • Halts fuel emissions


  • Congested keyhole

10. Stant 10510 Locking Fuel Cap

Highlighted Features

  • Vacuum relief valve
  • Pressure relief valve
  • Emission controllable
  • High-grade lock
  • OEM quality construction

Last but not the least, this position of our top product list is occupied by the Locking Fuel Cap from Stant. By now, you can easily do the guesswork of how the Stant is dominating the market.

It comes with a vacuum relief valve, which helps to maintain normal air pressure in the tank at the time of a normal vacuum situation. It also prevents the vapor from flowing outside while letting air get inside via the fill tube.

In addition to that valve, it also boasts with a pressure relief valve. When the fuel tank gets collapsed, it will release the pressure from the tank resulting in less damage. Therefore, both of the valves act as the heart of the tank to run the fuel mechanism efficiently.

Plus, this Stant 10510 fuel cap performs a great task by preventing the emission of gas vapors into the air. As a result, less harmful elements get into the air.

Moreover, all the aforesaid things are possible owing to the secured seal on the fuel tank, thanks to the high-grade lock system. So, it will be able to deter fuel theft and vandalism ceaselessly.

Besides, you’ll also get two keys with a round or square bow at the end. And they both can carry out the work properly.

Moreover, to perform all these tasks, it should have the quality of surviving lots of rigorous days and nights. No worries, since this gas tank cap from Stant has been constructed from OEM materials, it will serve you for a long-time.


  • Controls pressure
  • Prevents vapor flow
  • Reduces pollution
  • Very easy to lock
  • Long-lasting


  • You may face a hard time inserting the key 

Best Locking Gas Cap - Buying Guide

Since it is about keeping the gas inside the tank as well as preventing tweakers from stealing fuel, you need high security locking caps. Yes, you have broken your back while studying our products. Still, there are some features to consider before buying a gas cap. We have outlined those features underneath.


Since you are replacing an older gas cap and getting a new one, you need quality as like as the car company provided you with. Unfortunately, most of the aftermarket products wear off very soon, leaving you in a frustrating event.

However, many gas cap manufacturers use OEM materials for construction. These materials are supplied by authentic OE suppliers, ensuring durability.

There are also locking caps made of high-quality, rugged plastic, but going for OEM materials would back you up for a long time.

Pressure/Vacuum Valves

These valves are very important as they work like a breather in the tank filler. They prevent vapor from flowing outside, whereas making way to enter air into the tank.

The vacuum valve helps the fuel-air to stay at normal pressure throughout the ordinary vacuum situation. At the same time, the pressure valve helps to release the pressure from the tank after a sudden collision. In a nutshell, they flawlessly perform the task of preventing unnecessary fuel evaporation.

Locking Mechanism

Gas locking cap doesn’t really tend to give a hard time while installing. Because most of them easily sit on the filler neck, and all it takes is a twist to get it locked.

However, there are some caps that come with a pretty tricky locking method that might seal the fuel properly but can make you sweat at the gas station.

Again, some caps need to push inward for locking, which might take some effort from you after using it for a long time. Therefore, read the locking instruction provided by the manufacturer before you opt to buy a fuel locking cap.


Though many do not pay attention to the keys of a gas cap, it is the root of both ease and hardship.

Manufacturers mostly provide a square and rounded shape keys, and they both can perform well. That being said, try to buy a fuel cap that comes with two sets of keys. As a result, if you lose one key, you won’t need to go for pliers to break it.

Again, if the construction quality of the keys is flimsy, there are chances that they will break under pressure. Therefore, a 10$ fuel cap will cost you ten times more damage for repairing in the garage.

However, if you go for our products, you can rest assured that the keys won’t be a concern.

How to Install a Locking Gas Cap?

Firstly, of course, you need a locking gas cap; otherwise, how can you install one, right? You can get a cap in any automotive store near you. Besides, you can choose from our top products, which will definitely do the trick of saving fuel by providing a secured seal.

Then, you’ll notice that most of the replacement gas cap has a “leash” with them. Some of them carry O-ring that holds the cap from missing. 

Now, hold the new cap on the neck thread of the fuel filler and press it hard. Afterward, rotate it in a clockwise direction. Don’t stop until you hear the audible click sound. Make sure that it clicks; otherwise, it will make the system pressurized, which will turn on the engine light.

Finally, to operate the locking mechanism, insert the key into the cap and turn it in a clockwise direction.

Top Brands on Market

You’ll find lots of brands on the market that promise a secure seal on the fuel tank. But unfortunately, most of them don’t live up to their advertisement.

However, we have searched and did the crosscheck to finally pick the top brands on the market. These brands have earned a reputation by pleasing the customers with consistent service. So, let’s look at them.


The ACDelco started its journey 100 years ago and still ruling the automotive market with head held high. This company boasts GM Genuine Parts and aims to change the industry with more innovative and variable products.

When you are talking about real quality parts, the ACDelco, along with the GM Genuine Parts, is the authentic OE parts. 

The ACDelco boasts with Gold (Professional) parts that are high-quality and often regarded as an alternative to OE parts. 

They also manufacture Silver parts for General Motors vehicles. So, whether you drive a Buick, Cadillac, GMC, or most non-GM vehicles, they will back you up, providing all the parts you need.


This company started its journey in 1989 in Indiana. They had stepped in a versatile field of production throughout their industrial life.

Now, they are humbly fulfilling the demand of various individuals by manufacturing a lot of different products – OE style fuel caps, testers for fuel caps, thermostats with gaskets, radiator, and reservoir bottle caps.

Plus, the Stant also provides products for heavy-duty vehicles as well as construction equipment, etc. And most of their products are made in the USA, ensuring full safety for the consumers.

A praiseworthy and honorable achievement of this company is the armed forces “E” award in1944 for the production of the alluring 50-caliber machine gun shell casings.


Charles C. Gates had started this company in 1911 in Denver as a tire and rubber company. But things changed with the revolutionary invention of V-belt, and the Gates have never needed to look back again.

From the beginning until now, it has made a family of 15000 employees in 30 countries over 100 locations. Besides, they have a plethora of products in their inventory to please every consumer.

They manufacture products starting from power transmission components, water pumps, caps and thermostats, engine hose, and so on. With all the changes and achievements of Gates, one thing that remains constant is the quality and service to move the earth forward.


With the view to provide a thermostat solution, cap solution as well as engine management solution, the MotoRad started its journey in late 1958.

From then, it has been manufacturing products that meet or exceed OE specifications of consumers throughout the world. The MotoRad is also aware of you as well as the safety of nature. That’s why they only use the technologies and equipment that are purely harmless at daily uses.

That being said, it has managed to gain a couple of honorable achievements like the General Motors Supplier Quality Excellent Award in 2015, Gold at ACPN, and APPEX award in 2016. It has also been honored with AutoZone “WITTDTJR” award in 2017.


With the aim to provide first-grade products at a minimum cost, the CST started its journey. They make sure that each and every product meets the specification of original equipment for pleasing customers, along with providing the utmost safety.

They manufacture versatile products such as oil caps, fuel caps, thermostats, and radiator caps. Besides, the CST also produces cooling system tester and adaptors. It also boasts with state-of-the-art assembly along with packaging equipment within a 15 miles facility.

Benefits of Locking Gas Cap

Below are some plain and simple reasons why you should get one;

Easy and Affordable

We all have our problems in 24/7 day to day life. Since the world is getting expensive day by day, you cannot afford to lose gas at random. It’s not only about losing gas but also wasting money.

In that case, gas tank locks can make your life much easier and stress-free. Though apparently it only saves your fuel, it does a lot more than that.

Seals All the Way

Most importantly, locking gas caps strictly deter thieves from stealing or tampering gas. It also seals the tank and prevents the penetration of any foul element. Therefore, the car engine gets to operate smoothly.

Plus, there are hydrocarbons in the fuel that dissolves in the earth’s ozone layer resulting in harmful smog in the environment. However, the locking gas caps for cars prevent the emission of such elements in the air.

Safe and Sound

Moreover, it also ensures safety by enclosing the vapors inside the tank. Because vapors have high chances of catching fire by even a spark, and that can risk your life.

Therefore, the benefits of this such small and inexpensive fuel cap can bring about a huge change in your life.

Frequently Asked Questions

1. Is it essential to replace my fuel cap?

Yes, you need to replace your fuel cap if your cap is cracked or older than more than a few years. Most importantly, if the fuel cap is crushed or fails in the emission test, then you must get a new cap.

Because a leaking cap emits about 22 gallons of gasoline vapors in the air per year, according to Sun Oil Company research, and it also disturbs the efficiency of the car engine by manipulating the oil. So, replace the old fuel cap with a new one to save your money and nature.

2. I lost the keys of the gas cap; how can I remove the cap?

Don’t panic, though it will take some time to remove a fuel cap without the key, you have to take the stress, unfortunately.

  • Get a flat head screwdriver and insert it into the lock.
  • Turn it the same as a key.
  • With the locking pliers hold on to the cap tightly and give a hard twist in a counterclockwise direction.
  • Press down the fuel cap and rotate in counterclockwise.
  • Also, you can go to the local auto parts because fuel caps are often keyed alike. So, the key from another model might do the trick.
  • If nothing works at all, get ready to spend some cash on a locksmith.

3. How long can a gas cap last?

It is estimated that a gas cap can last about 50,000 miles. But the time may increase if it is taken care of properly.

4. What is the common error code of gas tank locks?

If your car shows “Check Engine” right after filling up the fuel tank, it is the indication of a loose gas cap. Well, “P0440” is the common code of a loose cap. However, it often directs in much more serious defects like a broken seal.

5. Is it ok if I drive with fuel cap light on?

Yes, it is ok to drive with a light on. Yet, it is highly recommended to use fuel cap; otherwise, during accidents or any collapse, the risk of high damage increases.

Final Words

You may say, 'Why will I have to get myself the best locking gas cap? I just can pick something out of random.'

Well mate, even though locking gas caps are little in size but trust us, they can solve your biggest problems sometimes. So, without giving it a second thought, you better get your hands on the one that suits your car. Safety is everything.

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