How Do I Unfreeze the Lock on My Gas Cap?

Finding your locked gas cap frozen can be more than an inconvenience, especially if you're nearly out of fuel and need to fill the tank. Although you can use hot water to unfreeze a gas cap lock, this could result in water leaking into the gas tank. If you're at the gas station, you may not have access to conventional methods such as de-icing sprays or hairdryers, but there are methods to unlock the cap without them. If you live in a cold weather climate or the lock freezes frequently, keep remedies for thawing it with you in the vehicle.

Things You'll Need

  • Gas cap key
  • Matches or cigarette lighter
  • Cloth
  • De-icer
  • Hairdryer
  • Cardboard cylinder
  • Heat the key on the engine while the car is running and try inserting it in the lock. If the key is warm enough, it will thaw the lock. You may have to repeat this several times. It's a handy method if you don't have any other method of thawing the cap available in the car. The key can also be heated with a match or cigarette lighter.

  • Wet a cloth with warm or hot water and lay it over the lock. Avoid pouring hot water on the lock, as this may compound the problem if the water refreezes or gets into the gas tank.

  • Spray de-icer on the lock and the key. Use it sparingly on the lock. Spray the lock carefully to avoid getting the de-icer into the gas tank.

    Heat or spray the key to thaw the lock.
    Heat or spray the key to thaw the lock.
  • Direct hot air from a hand-held hairdryer at the lock if you're at home, in a garage or close to an outlet that will allow you to use one.

  • Use a cardboard cylinder from a paper towel or toilet paper roll. Place one end over the lock and breathe through the other. Your warm breath may help thaw the lock. This may take some time.