Gas cap hard to remove - why?

[henryat1140]

For about six months the fuel cap on our 2000 Camry 4 cyl has been getting harder and harder to remove.

Is it a possibility there is vacuum holding it tight to the filler tube?

I've replaced the cap with a Genuine OEM Toyota cap. Gently cleaned the sealing surface at the end of the filler pipe to make sure there is no crud or rust there. The end of the filler pipe is clean and shiny. I have also used a little lubricant sparingly on the o ring on the cap to make it easier to put on and remove. (used lube safe for rubber)

My wife is afraid she will get to a point where she cannot get it loose to refuel the car. A secondary problem is because she is afraid of tightening the cap too tight it gets a CEL indication. That usually goes away after I tighten the cap.

Yet the fuel cap is still very stubborn to unloosen which brings me to my question: could there _possibly_ be a vacuum in the filler pipe which is causing this? I don't hear a giant 'whoosh' when you remove the cap, but am at a loss as to why it would be so hard to get loose.

Any ideas?

Thanks

Henry

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2000 Camry 4 cyl, mileage 160,000, regular maintenance. 5speed

[ghettosled]

but its not tough to screw it into place? if its a new cap, the check valve should be functioning as it should. i believe if you shake the cap, you should hear it ratting around.

have you replaced the filler neck recently? when i replaced mine, the cap was very tight to screw down on the new neck.