Locking Fuel Caps. Securing Your Fuel

August 17, 2008

Locking fuel caps have gained in popularity recently, driven in part by the rapid rise of the cost of fuel. Many motor coach owners believe that installing such devices may in fact lead to other issues if their rig is subject to fuel theft. So, is purchasing and installing these fuel tank security devices the way to go? Is the jury still out? According to many, no. So let’s look at the arguments on both sides.

The use of locking fuel caps on vehicles are primarily employed to prevent the unlawful access of the fuel entry for the purpose of siphoning the fuel from the tank. But they also service other purposes. They prevent the insertion of foreign materials or liquids into the tank such as may happen if children are playing in the immediate area or a malicious person attempting to cause harm. Additionally, they prevent an over zealous service station attendant from starting to fill your tank prior to you getting outside the coach. Gasoline has been put into a diesel tank or vice versa as a result of just that. There are also highly unlikely spin-off benefits, such as the prevention, or at least hindering, of filling the tank by a thief should the vehicle be stolen.

On the other side of the coin, are the people that believe that such a locking deterrent may in fact,cause a-would-be thief to resort to other methods. These other methods, such as cutting the fill tube or punching a hole in the tank, may cost the owner more than just the loss of fuel. While in theory this is valid, however, that being sound would also support always leaving your coach door unlocked, as it will prevent a would-be thief from breaking the window or causing like damage to gain entry.

Well, if you are on the side of the fence that wants them, where can you buy them. The best place is probably your local automotive supply house, like Pep Boys, Autozone, etc. If you have dual fill ports, as many coaches do now, you can find sets that have matched keys. This will allow one key to open either tank fill cap. But if you are unable to get a matched set for your particular unit, as happened to me, then you can color code one or both keys as I did. For me, the right hand fill cap uses the key with the red nail polish on it. Now, in most cases, if not all, you will not be able to cross reference the cap model that fits your coach. I guess the market in motor homes is not large enough to make it worth while for the cap makers to bother.

So, how do you get the right one for your rig? Well, there are two things you must match, size and type. The size is determined by the threaded portion and the sealing gasket. That can generally be visually matched with your old cap in one hand and the new one in the other. So for this part, don’t forget to take your original cap with you when you go cap shopping. Okay, now you have the right size. Is it the vented type or is it non-vented? Generally this will be indicated on the packaging. This must be matched with the same type as your vehicle requires. Failure to do this may result in activating the “Check Engine” light, poor engine performance, engine shutdown or all three.

Verifying whether your original cap is a vented or non-vented will not be as easy as looking it up in the vehicle manual. In most cases it is not listed in any of the vehicles documentation. So, you are going to have to determine that yourself. To do exactly that, do the following. Wipe off and thoroughly clean the threaded portion and inside of the old, or original cap. Place your mouth over the entire threaded sleeve. Now suck. No, this isn’t “Smile You’re On Candid Camera;” no joke, suck. You will find that a vented type will allow air to be able to be drawn in, but not blown out. If it is non-vented, you will not be able to draw air in or blow it out.

So, from following the above instructions, you can now select the appropriate locking fuel cap that will not only fit your coach tank fill port, but also one that will function in the manner the emissions system on your vehicle is supposed to operate.

So, what is the answer, locking caps or not? I guess there is no one-answer-fits-all here. Much of this decision is probably dependant on where the vehicle is parked. If it is in an isolated location where would-be-thieves could operate unobserved, the non-locking caps may appear safer. However, either way, you may have your fuel stolen or worse. I believe that locking caps may reduce the risk, if only keeping out the honest thieves. I suppose the best solution to reducing the risk of fuel theft and like losses would be to find a more secure location in which to store or park your RV. A location that would make it more visible and difficult for people to tamper with the vehicle, would go a long way to this end. But, regardless, the risk of fuel theft will always exist at one time or another. Locking fuel access will make it more of a challenge. A challenge many thieves may pass on. After all, there are lots that don’t have these, so why bother with the hassle.

Well, there certainly appears to be more reasons supporting the use of these than not. However, replacing the caps may not be for everybody. The loss of fuel may be far less costly than a damaged tank or fill tube. In this case, the caps may not be the only thing that one should consider changing. Moving the vehicle to a less crime risk area might be in order.

With Some Fuel-ish Thoughts – Lug_Nut – Peter Mercer