What could be causing a water leak in the boot of my BMW 320d saloon?

I have a 2008 BMW 320d saloon and have found water in the boot. It has gathered in the plastic tray sunk in the floor on the left side. I took the tray out to empty it and found more water under boot floor. I can feel some damp behind the boot wall lining, but this is not seeping through through the lining, just going straight down. Are there any known faults such as blocked drain holes, failed boot seals or failed light seals?

With reference to recent letters about winter wheels and tyres, during winter 2009 my car spent a couple of weeks parked up because I couldn't even reach the end of the street on my 18-inch M-Sport wheel/tyre combination. For winter 2010 I switched to 16-inch steel wheels with 205/60 mud and snow tyres and didn't lose a day's driving. Bowker BMW in Blackburn have been superb - they changed these over and delivered my alloys back home so I could clean/polish them over the winter and then reversed this in March.

Fuel consumption has also been good. It recently averaged 50mpg on a round trip to Frankfurt with my wife, two children, luggage and, on the return journey, 60 bottles of wine. All of this was at autobahn speeds of between 70 and 90mph.

Asked on 12 May 2011 by JS, Blackburn

Answered by Honest John
It is probably coming in through the cabin vent that is supposed to be a one-way flap to let stale air out of the cabin and is usually situated behind the sides of the rear bumper. Smart thinking about those tyres. I've got emails coming up through the summer to remind readers to buy them then rather than wait until the winter when everyone will want them, as supplies will be difficult and prices will be high. I got mine ordered in June.
Similar questions
I like driving my BMW 320d Touring. But it's not good in snow. Which car in the same price range is better in the snow/ice and Veras good to drive ?
If I were to purchase a couple of winter tyres for my BMW 320D Touring, would I be best served fitting them to the front or rear wheels?
I'm trying to decide on a one or two-year-old coupe that I can use to drive long distance, especially to ski resorts in Europe, so 4wd would be an advantage. The Audi A5 3.0 Quattro coupe seems ideal,...
Related models
Superb to drive. Great handling and steering. Upmarket image. Economical diesel engines culminating in amazingly efficient 320d Efficient Dynamics at 109g/km of CO2.
 

Value my car

Save £75 on Warranty using code HJ75

with MotorEasy

Get a warranty quote

Save 12% on GAP Insurance

Use HJ21 to save on an ALA policy

See offer