UK-POLOS.NET - THE VW Polo Forum

Hey guys, new here, and I’m not sure if it’s been answered before but I wouldn’t even know what to type in to find out (don’t know a great deal about mechanics) It’s rubber and it’s sticking out of the fuel tank, you can poke it back in but after a drive it just falls back down, not sure what it is, is it something I can replace or should be worried about?

Welcome to the forum. I see from your forum signature details that your car is a 6c GTI which I think may be relevant to the purpose of that rubber tube that you’re querying.

I was a little confused by your picture as it’s upside down. I’ve changed the orientation of the picture so the tarmac surface is now at the bottom of the picture;
That rubber tube (circled in the picture) isn’t from your fuel tank - it’s from the spare wheel well. In the picture below of the underside of a Polo, the spare wheel well is marked ‘A’. The fuel tank - marked as ‘B’ in the picture - is in front of the rear beam axle. The location of the rubber tube is arrowed - the underside of the car in the picture doesn’t have that section of rubber tubing, which I suspect may be specific to the GTI model only (the car in the picture isn’t a GTI).
I don’t know for certain what the purpose is of the tube but I would hazard a guess it might be either a drain tube or vent tube;

• From what I’ve read on various VW forums, it’s not uncommon for some models of VW cars to suffer water ingress into the boot when they get older (seems quite common on the Golf), which will run down into the lowest point of the boot which is the spare wheel well. If this did happen, as the battery is located in the spare wheel well in the Polo GTI, a drain tube would avoid a situation of the battery sitting in a pool of water.

• Alternatively, if a car battery gives off fumes (I’m not sure if it does?), then the purpose of that tube may be to vent the fumes out of the car.

Therefore, don’t poke it back in - leave it as it is as that’s how it should be. You can see the same tube in the pictures of the underside of another 6c Polo GTI in the discussion thread at the link below;

viewtopic.php?f=56&t=69884

I'd think that the boot mounted battery will have a battery breather hose, my S4 has its battery in the boot, and it has a small breather pipe from the boot side vent and passing out through the floor of the boot.

10/10 for working out that the picture was upside down - I thought that the grainy black stuff was sound deadening material!

RUM4MO wrote: Fri Apr 14, 2023 11:19 pm 10/10 for working out that the picture was upside down - I thought that the grainy black stuff was sound deadening material!

It had me stumped for a few minutes before I recognised the contours of the underside of the spare wheel well and realised it was upside down .

Yep battery breather tube