How To Unlock Gas Cap with key: Step-by-Step Guide

.A locking gas cap is an essential accessory for preventing fuel theft and vandalism in vehicles. 

Have you ever found yourself stranded at a gas station, unable to unlock your gas cap? It can be a frustrating experience, especially if you’re in a hurry or far from home. But don’t worry, we’re here to help.

In this guide, I will show you how to unlock a gas cap with a key. Whether you’ve lost your key or your cap is stuck, we have solutions that will save you time and money.

Table of Contents

Why Use a Locking Gas Cap?

A locking gas cap is a simple yet effective tool for safeguarding your vehicle’s fuel from potential thieves and vandals. With a key lock mechanism, it prevents the cap from being unscrewed without the correct key. 

This security measure can deter criminals from attempting to steal your fuel or tamper with your vehicle’s fuel system.

Benefits of a Locking Gas Cap

  • Protects your vehicle from fuel theft
  • Prevents fuel system vandalism
  • Increases overall vehicle security

Before diving into the process of unlocking a gas cap with a key, it’s essential to understand the necessity of having the key on hand when approaching the gas pump.

How to Unlock a Gas Cap with a Key: Step-by-Step Process

Follow these simple steps to unlock a locking gas cap using a key successfully.

Step 1: Unlock the Fuel-Fill Access Door

Some vehicles with electric door lock systems will secure the access door over the gas cap when the car is locked. To unlock the fuel door, simply unlock a door on the car. Other vehicles may have a lever under the dashboard or driver’s seat that unlocks the fuel door.

Step 2: Insert the Key

Slip the key into the slot on the center of the gas cap, ensuring that the teeth are facing the outer circle.

Step 3: Turn the Key

Rotate the key clockwise, allowing the lock cylinder to give way and move the key.

Step 4: Unscrew the Gas Cap

Turn the gas cap counterclockwise, unscrewing it until it is entirely off the threads.

Step 5: Replace the Cap and Tighten It

Insert the key back into the slot, holding the cap in place with one hand while turning the key counterclockwise. Remove the key and check the lock by attempting to open the cap.

What If You Lose the Key or It Breaks?

In the unfortunate event that you lose your gas cap key or it breaks, there are alternative methods for removing a locked gas cap without a key. Keep in mind that most of these methods will require you to replace the lock or gas cap.

Use a Flat-Head Screwdriver

Insert a flat-head screwdriver into the lock, like a key, and twist in the direction that would unlock it. These locks are generally not very strong, so this method should work.

Use Locking Pliers

Grasp the gas cap tightly with a pair of locking pliers and provide a strong twist counterclockwise. The bars that hold the lock in place should break as a result.

Visit an Auto Parts Store

Local auto parts stores often have a variety of gas cap keys, and since most gas cap keys are similar, a different key might work. If you prefer to avoid the hassle, the store will likely be happy to sell you a new cap.

Use Liquid Nitrogen

A less conventional method involves drenching the locked gas cap in liquid nitrogen and twisting the cap with a pair of pliers. This should break the cap into pieces.

Consult a Locksmith

If none of the above methods work, your final option is to visit a locksmith. They may have alternative ways to pick your lock, but be cautious if they decide to drill out the lock, as small metal pieces could enter the gas hole and block the fuel filter.

How do you lubricate a gas cap?

Lubricating a gas cap is an easy process that can be done with a few simple tools. Here’s how you can do it:

  • Get a can of silicone lubricant: You can buy silicone lubricant from any auto parts store or online.
  • Clean the gas cap: Use a clean cloth to remove any dirt or debris from the gas cap.
  • Apply the lubricant: Spray the lubricant around the keyhole and the edges of the cap. Make sure you cover the entire surface area of the cap.
  • Wait a few minutes: Let the lubricant sit for a few minutes to allow it to penetrate the lock.
  • Turn the key: Try turning the key to see if the cap opens. If it doesn’t, you can try tapping the top of the cap lightly with a rubber mallet.

Preventing Future Issues

To avoid problems with unlocking a gas cap in the future, consider the following tips:

  • Always keep your gas cap key in a safe and accessible location.
  • Regularly inspect your gas cap and key for signs of wear and damage.
  • Replace your gas cap and key as needed to maintain optimal vehicle security.


A locking gas cap is an essential accessory for safeguarding your vehicle’s fuel from theft and vandalism. By following the step-by-step process outlined in this guide, you can easily unlock your gas cap with a key. In case you lose or break the key, follow alternative methods available to remove the locked gas cap. 


Can you drive without a gas cap?

Yes, you can drive without a gas cap, but it is not recommended as it can lead to several issues such as decreased fuel efficiency, fuel evaporation, and even the risk of a fire.

Can I use aluminum foil as a gas cap?

No, it is not recommended to use aluminum foil as a gas cap as it is not airtight and can cause fuel evaporation, decrease fuel efficiency, and potentially damage your vehicle’s engine.

Can an open gas cap cause engine light?

Yes, an open gas cap can cause the engine light to come on as it can trigger the vehicle’s emission control system. Therefore, it is important to always ensure that your gas cap is properly secured and tightened to prevent any potential issues.

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