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Solution to the fuel tank gas cap filler won't come off problem

32K views 13 replies 12 participants last post by  Simonhenryjames 
#1 · (Edited)
In the top photo, you can see a tab that sticks into the neck at about the eight o'clock position. There is another at two o'clock. When the cap is over-tightened, these tabs get squashed down flat against the flange, snagging the cap and making it extremely difficult to turn. The cap lock tabs get crosswise to the white plastic ring, and the whole thing gets jammed.

The fix is to pull those tabs out so they're are at right angles to the seating surface. On the cap, you need to rotate the white ring so that the lock tabs drop into the slots at the clockwise end of the "track" on the plastic. In normal operation, the plastic stays behind as the cap is rotated, until the lock tabs ramp down into the slot at the counter-clockwise end.

When replacing the cap, stop turning when you hear the "click."
 

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#3 ·
I have that exact problem except that it does not stem from overtightning. Every time the cap is removed, it is a huge ordeal and the white ring needs to be manualy reset via pair of screwdrivers and a few choice words. The cap once on simply does not want to come off. The only thing I can figure is something in the filler neck is worn and not working with the ring to get the toggles to release. Any other advise?
 
#4 ·
This has got me wondering so I compared my old and new caps. The one on the left is the one I bought when I was trying to track down the cause of a P0455 code. The gas cap was not the cause.

The one on the right is the cap that came with the car. It looks more like the OEM one except I have no idea where the tether gets attached.

They are both manufactured by Blau.

I am still using the aftermarket one. It simply goes on, turn to the right with a strong but smooth effort until it stops. The original one of course "clicks" when it is properly closed. They both give a satisfying "whoosh" of air when released. I did notice that the white ring is spring loaded. If you rotate it by by hand it promptly snaps back.

Is it possible that the spring is broke and that is what started all this.

I don't know if any of this info is useful. I am just throwing it out there.

Sorry for the PQ. I really need to get one of those Cazzle 1000s.
 

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#6 ·
In my search I came across this post. I have the same problem with my 98
SL500 - gas cap doesn't come off - it goes out of sink with the white ring.
Checking my tabs on the filler tube as per your suggestion they look like they are bent in. How did you bend them out without damaging the outer ring? I was using a screwdriver under the tab to bend it out but it seamed to be applying excessive force to the out ring and may distort it. I don’t want to replace the tank. This all started with a blinking gas gauge and I may have over tightened the cap. Any help is appreciated –Thanks in advance.
 
#12 ·
Part of the problem may be from the user's hearing over and over again from US automakers "click" gas caps to turn until you hear 3 clicks (or more) in order to make sure it is secured well enough to avoid the CEL coming on because the cap was not tightened enough.
 
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