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Modern Billet Locking Fuel Cap (05-09 All)

AmericanMuscle no longer carries the Modern Billet Locking Fuel Cap (05-09 All). Please check out 2005-2009 Mustang Fuel Delivery & Injectors for an updated selection.
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Features & Details

  • Locking Gas Cap
  • Extra Protection and Security
  • Billet Aluminum Cover
  • Black Anodized Finish
  • Includes Two Keys
  • Fits All 2005-2009 Mustangs
Extra Security. With the rising price of gasoline these days it is no wonder that locking gas caps have become popular again. Stop thieves from siphoning the gas from your tank (or an ex from adding something extra to your tank) with a Modern Billet aluminum locking gas cap.

Billet Aluminum Construction. CNC machined from high quality 6061 T6 billet aluminum, this Mustang locking fuel cap is completed in a black anodized finish for an aggressive appearance and superior durability.

Application. This black anodized Modern Billet Aluminum Locking Fuel Cap is a direct fit replacement for all 2005 to 2009 Ford Mustangs, including V6, GT, Bullitt and Shelby GT500 models. This locking fuel cap comes with two keys.

Fitment: 2005 2006 2007 2008 2009 Details

CA Residents: WARNING: Cancer and Reproductive Harm -

What's in the Box
  • (1) locking fuel cap
  • (2) keys
Installation Info
Tech Specs
Will it fit my Mustang?

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Questions & Answers (3)

3 Top Rated Questions

Does this help with a common problem with the 06 Mustang where the engine warning light comes up after a random gas fill up? A shop before said that the 3rd party cap I once had was causing the warning to appear, they changed it to an OEM fuel cap and it stopped the warnings.

  • The Modern Billet Locking Fuel Cap is simply designed for extra security. It will seal just like the stock cap.

Helpful (0)

Can xopies of these keys be made easily? I have had a locking cap before and couldn't get copies made. I like to have extra copies as I would like one for home and have 3 sets of key rings. Thanks.

  • Hello! It is possible to have copies of the keys made. However, we have found that some customer's have difficulty finding the right local hardware store to get the key made at.

Helpful (0)

When locked does the cap spin freely.

  • yes it does. It does this so that it cannot be forced open by brute force. I know, because i've tried pretty hard to force mine off to see how well it worked. It's great quality and was worth the extra few bucks.

Helpful (0)
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Customer Reviews (19) Write a Review

Overall Rating 4

out of 5 stars

  • 2/5

    February 10, 2018

    Overpriced and needed shims

    This is essentially the same locking gas cap you can get at Autozone for about $20 coupled with a fancy looking metal outer cover (what you see in the picture). The fit is not precise which required me to shim the coupling surface. It would have helped if the cap utilized four allen screws instead of only two. Ultimately this disappointing and costly purchase was my fault for not shopping around first.


    Year: 2006 Submodel: GT

    Helpful (2)

  • 3/5

    December 28, 2017


    Gas cap was good, but my factory gas door wouldn’t close all the way, gas cap is to big


    Year: 2009 Submodel: V6

    Helpful (3)

  • 4/5

    December 16, 2017

    Nice quality item with one small problem

    The gas cap is really nice quality and feels nice and bulky. The problem with that is if you have a aftermarket fuel door then it will be almost impossible to lock the cap. Otherwise the cap is well worth the money.


    Year: 2007 Submodel: V6

    Helpful (4)

  • 1/5

    December 09, 2017

    Lies all Lies

    This product does not work. Maybe I got a lemon i don't know, haven't had the time to call and sort out a possible replacement. With mine the key would not even rotate around enough to "lock" it would go about half way and then get stuck. Also no matter how I placed the cap in the Fuel port and worked the key, nothing actually locked i could always just unscrew the cap. This is the first time I've gotten a dud from AM so it must of been my unlucky day.


    Year: 2005 Submodel: V6

    Helpful (3)

  • 5/5

    December 03, 2017

    A little flare

    Awesome addon. I like the addition of this gas cap and the added security


    Year: 2006 Submodel: V6

    Helpful (3)

  • 4/5

    November 25, 2017

    Fuel Protection!

    It's great to give my fuel tank a bit of protection, my only gripe is that the bulk of the cap makes it difficult to loosen or tighten, other than that, this was a great investment!


    Year: 2007 Submodel: V6

    Helpful (3)

  • 3/5

    November 03, 2017

    Billet Cover Should Be Optional

    There is only one problem with this locking gas cap and it's billet cover. I have an after-market fuel door on my 2006 Mustang GT. The frame for that door attached to the body reduces the opening to the filler pipe. There is no way I could attach the billet cover and use that locking cap and I have fairly small hands. AM should make the billet cover optional. The locking cap by itself works fine. Not having to pay for the billet cover should reduce the price for those Mustang owners who can only use the actual locking cap.


    Year: 2006 Submodel: GT

    Helpful (3)

  • 3/5

    September 21, 2017

    Tight fit

    It's big and hard for fat hand to twist out. With the key and twisting become difficult.


    Year: 2005 Submodel: GT

    Helpful (3)

  • 5/5

    August 11, 2017

    My little red pony

    I love it at first I tightened the little Allen screws too tight and it wouldn't let the fuel cap twist on the gas tank so I loosened it up and it was fine . As soon as I did that your gas cap will spin . It looks great l love this product.


    Year: 2006 Submodel: GT

    Helpful (3)

  • 5/5

    March 30, 2017

    gas cap

    Easy install and a great look, vary happy and I would recommend to everyone


    Year: 2005 Submodel: GT

    Helpful (4)

  • 5/5

    January 24, 2017

    Solid product

    I like the weight it has to it and looks much better than the plastic stock unit with a bonus of locking which has really been the main reason of getting this since the gas door doesnt lock on these cars


    Year: 2006 Submodel: GT

    Helpful (4)

  • 4/5

    December 27, 2016

    Ease of Mind

    Let me start by saying I can finally relax knowing someone can't just walk to my car and have access to my gas tank. When you first receive the package you have the cap and the Billet cover with 3M tape underneath to adjoin the two. No set of instructions are inside, but installation is straight forward. It is a little bulky, but overall it's a great item if you want piece of mind plus a great item to look at!


    Year: 2008 Submodel: V6

    Helpful (4)

  • 4/5

    June 11, 2016

    Love it

    Love it protects my fuel tank from some people who keep messing with baby. The cover is a little too big but I like it anyways All in all a great buy


    Year: 2007 Submodel: GT

    Helpful (3)

  • 5/5

    April 03, 2016

    works very well

    fit is a little tight but it works like a charm. it's not gonna come off. definitely recommend if you don't want anyone messing with your gas tank.


    Year: 2008 Submodel: Bullitt

    Helpful (4)

  • 5/5

    August 23, 2015


    I live in a town home community and park outdoors year round. I feel much better knowing that I have a secure locking gas cap on my Mustang versus my car being wide open to any type of tampering or gas theft. Nothing is guaranteed but a deterrent is always a good thing to have.


    Year: 2009 Submodel: GT Springfield, Virginia

    Helpful (4)

  • 4/5

    January 20, 2015

    Big and locking

    This a nice stylish locking gas cap. The good thing about it is the top part is made out of metal. Not plastic like most. However, if you have one of the Aftermarket fuel doors like I have. Think carefully about getting this because it will fill up most of the opening which can make it a little tough to remove the cap. Only reason I didn't give this a 5 star rating is because of how bulky it is. I'd still recommend this item.


    Year: 2008 Submodel: V6 Altona, NY 12910, USA

    Helpful (3)

  • 4/5

    December 23, 2014

    Cool billet look

    This piece looks great. Nice retro billet look and love that it's black. It is very big though...almost 2x the size of the OEM cap. I have the key on my keyring and it's kind of a pain to take the cap on and off but that maybe due to the after market fuel door I have. Very happy overall though and would definitely recommend this!


    Year: 2008 Submodel: GT500 Orlando, FL, USA

    Helpful (5)

  • 5/5

    December 19, 2014

    product improves safety

    I got the locking fuel cap both because I was going away to college and just wanted that extra safety feel that my car got while I was away from her. It is a nice piece to have in my opinion. Really is unique and overall keeps people out of doing anything to your gas


    Year: 2009 Submodel: GT Cincinnati, Oh

    Helpful (4)

  • 5/5

    December 03, 2014

    Great gas cap

    wanted a locking gas cap because i do not like the idea of anyone being able to walk up to my car and opening the gas cap and then either adding or taking anything out of the gas tank. I chose this one because i liked the black finish. to me, this was worth the extra 20 bucks over the other locking gas cap AM sells. This gas cap does exactly what i wanted it to do. key goes in fairly easy and turns without a problem. Once the gas cap is locked, it does not come off until unlocked. I gave this things a few good tugs in all ways to make sure it dosnt cheaply come off if your turn it enough like most cheap ones do. Other thoughts: -the paint on the black metal cover comes off and dings pretty easily, so be careful putting it down -while playing around with the lock, i noticed that it is much easier to lock the gas cap BEFORE putting it back on. this makes it easier to lock the cap in place -If you have an aftermarket fuel door, be careful. mine is aftermarket and just BARELY clears the fuel cap. Although if yours does not clear, you can always remove the black cap cover, leaving just the plastic fuel cap that has the actual lock on it. Overall, this was a great purchase. If you are like me and are paranoid about having your fuel tank fully accessible, buy this. After looking for years for a good one of these, this is the first one that actually locks correctly and dosnt come off with just a few turns. its well built


    Year: 2009 Submodel: GT New york

    Helpful (4)

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