Vacumatic
Testy
The car is a VW convertible. Older convertibles such as the MGB used to have a flap on the hood which directed the rainwater outside the car, Karmann build the car for VW and the design allows water to go into the car and out of the drain holes.How is water getting in, in the first place? Have you checked for rust?
There is also a known fault with vents behind the rear bumper which allow water from the road to gather in the spare wheel well and that finds its way into the car.,
The wheel well had about four litres of water, surprisingly clean water. No sign of rust to the body or the spare wheel.
There is a German specialist seller of these cars and they say that 90% of the cars that come to them have damp carpets, some have problems under the rear seat too..
The cause is guesswork on my part and seeing what others have done to fix the problem, to do things properly means removing the rear bumper and as long as the problem has gone away then I am hoping that chore will not be necessary.
The puzzle to me is that the water looked new and clean, both from the sills and the wheel well. The car is 11 years old now, no idea as to how long this has been building up.