A Class fuel tank 'thump'

[maldon]

Mr Stupid will of course now post this in the correct area........


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The wife's A Class is making a strange 'thump' a few seconds after she parks, switches off and locks the car.

We've had the car along to Mainlymercs in Colchester (as usual, brilliant service) - they are sure it is from the fuel tank expanding, after it has contracted a little.

The fuel filter has been changed - but the problem still exists - the MM lads think it may be a problem with a blocked charcoal filter/vent.

Anyone have any experience, ideas or pointers?

Thanks.

 

[Splatt]

Not a thump but it could be related !! Sometimes when I pull into a petrol station on removing the filler cap I get a distinct hiss of air entering, as if the petrol tank is under negative pressure. I wondered is this was a function of a petrol vapour recovery system or if their should be a vent and it is not working. Car is 6 months old now. ( A class Petrol ).

 

[maldon]

Thanks, Splatt - there appears to be nil pressure when the fuel filler cap is removed.