Leaks with Passat (Mine is a 52 saloon) are usually caused by water ingress through the pollen filter, due to breakdown of the foam seal, or the other main cause is a drain hole under the battery clogging with silt or debris.
My car suffered from water in through the pollen filter which turned the passenger side of the car into a swimming pool. Luckily for me it didn’t short out the cars computer which is located (of all places!) under the carpet in the front passenger foot well, and would have cost £££'s to replace if it had failed. It took me 3 days to dry the car out completely, and in the end after much wrangling with my local dealer I managed to get them to change the filter seal free of charge, which is the least they could do since they should have spotted it during the car's numerous services with them. It's a known fault which Volkswagen is all too aware of!
MikeW, March 2008
