Strange noise from Petrol Tank

[petros]

Very strange thump from petrol tank, first time in the 5 months I've had the car. Happens as soon as the pumps prime, is it anything to worry about ? Peter

[2 Smokin Barrels]

Carbon filter might need clean.

[petros]

Carbon filter cleaned last month. Don't mind the noise as long as It's no problem. Just curious as to why It's suddenly started. Peter

[parrot of doom]

Mine has done this a few times recently, most often when I've filled it up. I just presume its the sides of the tank being sucked inward.

[ricardinho]

I remember being quite worried last year when I got my car, until i found out what it was. It tends to happen to me in the summer (warmer) months only. Happened for the first time this year at the weekend....

Think of it as the tank being happy in the knowledge it's about to go on a diet (lose weight)

Enjoy!
Love the colour and 'waxed to buggery' ness of your car. Is that Cooper green?

Richard

[petros]

It's Boston Green liberally waxed with Meguiars NXT Wax. Peter

[middxtvr]

lol........was reading this thread this morning thinking that sounds a bit weird..and sure enough this afternoon after 5 months of ownership happened to me..... i better stop reading b4 anything else happens!

[M@H]

Well contrary to everyone elses posts I don't think this is the case.. if the thump from petrol tank happens as soon as the pump primes I'm assuming this is after the car has been sat about and not been used, and is just being fired up. If this is the case, the tank pressure should have "normalised" to an extent in the intervening hours (overnight?) since last use as even a blocked carbon cannister will trickle some air to it, plus the petrol cap seal will probably have tricked slightly.

The clanking tank collapse noise comes from the fact that the canniser can't get a gallon of air back into the tank every 20 minutes (20mpg @ 60mph) or so.. I'm convinced that there isn't a total block of air with a "blocked" cannister, or the car may well stall as the fuel pump fights to expell the last few gallons of fuel against 7 gallons of practical vacuum... in fact, wouldn't the petrol vapourise..? ()

Anyway, back on track.. a thump on starting the car up from standing overnight I would NOT have thought was the tank collapsing as per the "TADS" syndrome.

Cheers,
Matt