Skip the auto shop - Our mechanics make house calls
  1. Home
  2. Articles
  3. How To Install a Locking Gas Cap

How To Install a Locking Gas Cap

gas cap with a key

Gas caps can fail due to a number of reasons. A leaking fuel cap can lose you upwards of 2% of your gas from evaporation.

Gas caps get cranked on week after week, month after month, and year after year. They leak around their seals, the threads can become damaged, and the ratcheting mechanisms can fail — just to name a few of the most common issues. Most states have emissions testing standards that test the amount of evaporation coming from gas caps.

Severe leaks in the gas cap cause the fuel pump and engine to work harder than usual. The harder the engine works, the more exhaust fumes are sent into our environment, causing additional damage.

Use one of the following procedures to replace a failed or leaking gas cap on your vehicle.

Part 1 of 2: Install a locking gas cap

Material Needed

Step 1: Buy a locking gas cap. When upgrading or replacing a gas cap, purchase a locking cap for your vehicle. This type of fuel cap can be found at automotive stores or online.

Gas caps are necessary for proper gas tank function. If the fuel cap on your vehicle is missing or broken, replace it immediately. Fuel efficiency can vary depending on the quality and the seal on your gas cap.

gas cap leash connection to the vehicle body

Step 2: Secure the cap leash. Replacement caps often come with a “leash” or plastic ring that keeps the cap from being lost. Secure the cap leash with its peg on the vehicle side of the leash.

pressing new cap into place

Step 3: Press the new cap in place. Press the new cap flush against the fuel filler neck thread and rotate clockwise until it “clicks” into place. The audible click verifies that the cap is sealed.

  • Note: Never force anything into place on your vehicle. A new cap should screw easily into place without any serious resistance.

Step 4: Put the key into the gas cap. Insert the key into the gas cap and rotate it clockwise to engage the locking mechanism.

  • Note: Always test the gas cap and ensure that its locked. Most caps swivel and do not engage the threads while the cap is opened.

Part 2 of 2: Install a non-locking gas cap

Materials Needed

Step 1: Buy a replacement gas cap. Replacement gas caps can be found at automotive stores or online.

securing the gas cap leash

Step 2: Secure the cap leash. Replacement caps often come with a “leash” or plastic ring that keeps the cap from being lost. Secure the cap leash with its peg on the vehicle side of the leash.

Step 3: Press the new cap in place. Press the new cap flush against the fuel filler neck thread and rotate clockwise until it “clicks” into place. The audible click verifies that the cap is sealed.

  • Note: Never force anything into place on your vehicle. A new cap should screw easily into place without any serious resistance.

Gas caps are a critical part of your fuel system. If you need to replace the gas cap on your vehicle, buy a replacement gas cap with a lock. Replacing it is as simple as connecting it and screwing it in.

If you need assistance in replacing your gas cap, contact a professional mechanic, such as one from YourMechanic, to do it for you at your home or office.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
Icon-warranty_badge-02

Skip the repair shop, our top-rated mechanics come to you.

At your home or office

Choose from 600+ repair, maintenance & diagnostic services. Our top-rated mechanics bring all parts & tools to your location.

Fair & transparent pricing

See labor & parts costs upfront, so you can book with confidence.

12-month, 12,000-mile warranty

Our services are backed by a 12-month, 12,000-mile warranty for your peace of mind.

Get A Quote

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE

More related articles

Veteran and Military Driver Laws and Benefits in New Mexico
The state of New Mexico offers a number of benefits and perks for those Americans who have either served in an Armed Forces branch...
Auto Safety Tips
Driving is more than a way to get from point A to point B. Owning and driving a car can also be a highly enjoyable experience. Whether a person is driving...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...


Related questions

Q: Car shut off at the traffic light - 1994 Jaguar XJS

This is most likely a fuel pump fuse or fuel pump relay acting up. Given the age of your Jaguar, electrical power to the pump is quite likely. Have a professional mechanic, like YourMechanic, inspect the stalling issue and proceed...

Q: The gas cap on my car broke off. (The black knob you use to screw in the gas cap.) The gas cap is stuck securely in the fuel neck. How can I remove it?

Hi there. To remove the gas cap that broke off, get a pair of needle nose pliers and use it to remove the gas cap. Try to locate a part of the gas cap that you can grab with the...

Q: Losing gas when my car is going up a hill

In many cases, the issue you're describing is caused by either a small crack in the fuel cell, fuel lines connections, or a damaged fuel line itself. If the issue is towards the rear of the vehicle, and severe enough,...