Skip the auto shop - Our mechanics make house calls

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

P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the P0052 code means This code is seen when the Engine Control Module (ECM) tries to control the...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
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...


Related questions

Q: If you got rocks in your gas tank, is it a big problem?

Hello. The problems you will have will be hearing the rocks move when you stop or take off. The other problem will be if the rocks were real dirty and may clog the pump or filter. If the vehicle has...

Q: How do you remove the gas cap?

Without removing the gas cap, you won’t be able to fill your tank. Nissan makes it easy to remove and replace your cap, and even provides a handy holder for the cap during the filling process. Here’s what you need...

Q: hose sizes

You would most likely need to talk to a parts department at a dealer to get specific part information like this. Unless each hose is measured and identified by a mechanic, I would find it hard to identify the exact...