Locking fuel filler caps?
 

So as I pumped 60-odd dollars into my tank, it occurred to me that there was nothing to prevent someone of low morals from stealing my car's precious fuel (I've disabled my vacuum-locking system).

I have a locking cap on my gas car but I don't think that would fit the mouth on my 240D. Is anyone using a locking cap on their vehicle?

motivation
 

It might be motivation to fix those vacuum leaks, right?

MB locking fuel fillers caps are rare, but available. They pop up on eBay from time to time.

Fix the vacuum system, MB already provided you with a locking fuel door.

The vacuum system on that car is pretty simple, it shouldn't be to hard to find the leak/s.

The part number for the fuel cap is 123-471-02-30, it comes with two keys.

Great! Thanks!

Did the 300CD come with a locking fuel filler door? Mine doesn't seem to have one, and I haven't been able to locate any switch to operate one either.

Problem with the locking fuel filler door is that most of them can be pried open with a big screwdriver - doing lots of ugly damage to your bodywork and paint in the process. A locking cap on the other hand is a bit tougher to defeat, and if they try they are at least somewhat less likely to damage the body in the process.

I think I'm going to look for one of those locking caps myself. Wonder if anybody made an aftermarket? Probably not - who ever thought diesel would be expensive enough for 20 gallons or less to be worth stealing?

On mine, the fuel door locks when you lock the doors and vice-versa...

Paranoid thinking.........If someone tried to steal the little bit of diesel from an MB it would probably be some punk trying to put it in a gasser. Then you could laugh when their car became disabled on the side of the road.

Besides, it would be much easier to crawl under the car and disconnect the flex hose at the bottom of the tank rather than try and pry open the fuel door......OOPS, I believe I just gave away my secret.:eek::D

Is that really a problem? Do you really think a gas thief will pry it open with a screwdriver? My bet is that he'd take his business to the next car...

You know, I never thought of trying to open it when the doors were locked. I just tried it and lo and behold, it is locked up tight!

Here's one for you though. I also tried unlocking the doors (from the driver's side) to see if it would unlock and it didn't! Weird! The passenger side door unlocked automatically as it should, but the filler door remained locked. Is there some trick to it? Every time I've gone to put fuel in it it has been unlocked - which is why I didn't even realize it automatically locked. Is there an emergency release or something?

The last thing I want to have happen is to pull into a station to fill up and find I can't get the filler door open!

If they will hijack a fuel truck, anything is possible. There have been reports of fuel thieves punching holes in fuel tanks as well.

At my work they dont even take the cap off.....they punch two 3/8" dia drill holes in the tank with a battery operated drill. One to catch fuel from and the other as a vent. When thier 5gal can is filled they leave and let the rest drain into the gutter.

Where exactly do you work? :eek:

Try double twisting the key in the door and see if that unlocks the fuel door. If not, try the central lock/unlock button inside. I also think there' s way to get at it from inside the trunk but I don't know if that carries back to your model year...