I had a friend many years ago who had a mini that smelt of petrol, There was supposed to be a vent pipe from the top of the tank but it had fallen off. So he blocked the hole with plasic filler.
During the next week or so there were mysterious boing sounds from the back of the car.
When he went into the petrol station to fill up he could get only 2 gallons in the tank as it had been crushed by creating a vacuum inside it.
