2009 Cadillac Sedan without an external locking door to the fuel tank

Who Loves You guys?
Well, I was gonna say, “I do! I do!” But then you’d probably read into it too much and ignore my question.

My Mother has a friend who just bought a 2009 Cadillac Sedan (STS, I think. With a V8—not the juice, that’s ‘V-8’).

But here in rural PA, it isn’t uncommon for drivers to have their gasoline siphoned in the middle of the night. He’s wondering why the outter gas tank door doesn’t lock. Suggestions? Thanks

I love…er…great job, guys.

Sadly, many US-make cars lack a locking gas door.
While this feature is a given with Japanese-design cars, it is frequently not included when designing US-make cars.

However, I can virtually guarantee you that there is a locking gas cap available for this car. Rather than risk a crappy-quality aftermarket locking cap, I suggest that the car’s owner visit the parts department at the local Caddy dealership. More than likely, they can order a locking gas cap for her.

Thanks VDCdriver! We talked to the local Caddy dealer, where he bought the car (just last week). The guy just shrugged and said, "this-here-vee-hickle didn’t come wit’ no gas cap that does that (meaning, ’ locks’.) I’m thinking his only alternative may just be an aftermarket model.

Any other suggestions? Appreciate your help.

I think your car has an internal check valve in fill tube to prevent fuel spillage in a rollover accident. I do not think you or any thief can insert siphon tube down fill port.

are you talking about a gas cap, or the door that protects the gas cap?
I haven’t seen a locking door in several years, most have a lever you pull inside the car to open the door.

Check your local auto parts store for a locking gas cap. Pep Boys, Advance Auto Parts, and any other similar store should sell them. Here’s an exact fit at Advance Auto Parts as an example:

I had a roomate in college who owned a VW Beetle; I don’t think he ever purchased gasoline for his Beetle the whole time I knew him, like for 2 years. He’d go out about 2 am, come back, I say “where did you go?”, he’d say “Oh, just getting some gas”. He must have had midnight siphoning perfected to a science.

hmmm … for you? … Maybe first thing is try to siphon gas out of the tank, see if it is even possible. New cars, what with all the evap controls, can’t be siphoned, at least in the usual manner. If you find you can siphon from this car, as mentioned above there may be locking caps available, or I’ve seen spiral wire gadgets which are inserted in the inlet tubing (like an IUD) which allow the gas to flow to the tank while blocking siphon tubing. Google should find them for you. Here’s one I found on just a quick look-see.

I’d reconsider the locking cap. Around here, they’ll punch a hole in the tank. Now would you rather replace a tank of gas or a gas tank? Some of the repairs are up to $1000 and delays for parts and shop time.


Where I’m at, they’ll crawl under your truck with the cordless sawzall and steal your cat in broad daylight, while you’re in the store.

I’ll just echo the recommendation to make sure the locking cap is designed for your car. I bought one for my VW GTI (from the dealer, even) and it didn’t work, gas leaked out when the tank was full (didn’t leak with the regular cap). This was a BIG problem, the gas-fired water heater was in the garage! Luckily, no BOOM…

+1 to Bing. Buying a locking gas cap is just an encouragement to use more destructive means (like an ice pick) to get at the go juice.

It’s like how every motorcycle I’ve owned has a locking cap…but has the petcock and rubber fuel hose out in the open. Even if the cap was missing, I’ts stil simpler to just stick the jerry can under the fuel selector and let gravity do its thing.