Audi A4 Avant - Dented fuel tank

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Mon 28 Apr 2014 13:48
Audi A4 Avant - Dented fuel tank - pritchaa

Hi - mine is a 2008 model, a4 avant 2litre diesel. All running fine and done 75k miles. Cambelt was changed last week and the guy said there was a dent in the fuel tank, not huige but it had been mishaped. He suggests it may be a blocked breather. This would mean having a whole new fuel tank at £1100 inc labour,. I cannot understand why just a new breather is possible but Audi say it is not. I can live with a slight dent in the fuel tank as it still takes over 80 quid to fill it!! so the dent is not that big. My concern is if the fuel tank continues to shrink which i will recognise, but what about if it shrinks so quickly that the fuel cannot be sent to the engine - - i dont want to cut out on the motorway!! Any suggestions??

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Mon 28 Apr 2014 13:57
Audi A4 Avant - Dented fuel tank - gordonbennet

Second opinion, obviously.

Have you removed the cap during a trip, is there a vacuum, if not then maybe the dent is physical damage and not vacuum.

If there is serious vacuum maybe try a new cap.

If the breather really is the case and its not replaceable, though that seems bizarre, i'd be inclined to drill the tiniest needle sized hole through the old cap that you can and see how things go, obviously have to not brim it quite so full.

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Mon 28 Apr 2014 15:19
Audi A4 Avant - Dented fuel tank - bathtub tom

>> i'd be inclined to drill the tiniest needle sized hole through the old cap

Might that make it fail an MOT? I've noticed the tester removing my filler cap and as soon as he hears a hiss he replaces it.

Modern fuel tank venting and breating systems baffle me.

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Mon 28 Apr 2014 15:50
Audi A4 Avant - Dented fuel tank - skidpan

Drilled a 1mm hole in the filler cap of my classic in 1993. The original cap was vented, the replacement was not thus the tank did not vent. Hole still there 21 years later and tank still intact.

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Wed 7 May 2014 15:38
Audi A4 Avant - Dented fuel tank - pritchaa

Thanks for your comments! I took it to audi main dealer and they put it on a ramp and reckon they saw a scrath mark on the dent and say it has been caused by an impact. However i went on a long run of 130 miles at the weekend and when i got there i removed the cap and the noise was verty clearly a vacuum that had got worse since i last removed the cap.

When you say replace the cap do you think the cap is a breather system on its own??

How do i find out if the breather pipes are genuinely an integral part of the fuel tank and that the whole things needs replacing at mega bucks?

Also how do i drill a tiny hole? how small are you talking?

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Wed 7 May 2014 15:58
Audi A4 Avant - Dented fuel tank - jc2

On modern cars,the cap should seal-it's part of the evaporative emission system.

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Wed 7 May 2014 18:47
Audi A4 Avant - Dented fuel tank - Andrew-T

Yes, you don't see many vehicles these days with an old rag sticking out of the filler ... :-)

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