RS3 Strange bubble/dollop noise from rear end

[kryten22uk]

There is a very distinct bubble noise coming from the underside of the rear of my RS3. It happens almost exactly once a second. It sounds like a large bubble going up through liquid and popping. Would usually expect to associate this with a hole which is dripping liquid, but the underside of the car is bone dry, and nothing dripping onto floor.

Is there something in the inner workings of the car that can cause the sound. Something related to the rear?

Video link below:
https://photos.app.goo.gl/ykKGTvhrVaSTgaTJA

[waxaholic]

How strange, is that coming from inside the fuel tank ?

[kryten22uk]

waxaholic said:

How strange, is that coming from inside the fuel tank ?

No idea! I dont know enough about mechanics. But the fact that it is at the rear of the car, must surely limit the number of things it could be.

[waxaholic]

It may lead to nothing but i would remove the fuel tank cap and have a listen, i'm guessing fuel tank breather or fuel return, considering that nothing else at the rear of the car holds gallons of liquid i can't think of anything else,
it does sound like a air bubble.

[kryten22uk]

Thanks, that sounds a sensible option. As you can imagine, I'm not using the car much at moment, but went in it today, but the noise was no longer present. Next time it is, I'll check to see if opening the fuel cap releases the pressure.