2014 420D Convertible - water in rear panels, blocked drain issue

[Gadgetman20]

I'm having big issues with my 2014 BMW 420D Convertible and my local dealers, Ocean Falmouth. My rear drivers side window wouldn't go down. Before calling the dealer I quickly googled and was horrified to see video after video of similar 4 series convertibles ..... all with gallons of water collecting within the rear panel and destroying window regulators and amps.  Turns out the cause of the problem is due to a bad design where the drainage plug underneath the rear panel is blocked off by the undertray and side skirt - pinned up against it with no holes to allow any water to pass out unobstructed.
It seems the undertray etc is the same one used for the coupe which had fixed, sealed rear windows where very little, if any, water can enter the panel. However the convertible has motorised windows and as such, like any car with opening windows, some water will always find a way inside the door regardless of the condition of the seals. This would be fine for the convertible if the undertray was changed by design to allow this dirty water to freely flow out.... but it isn't.... so water is soon trapped as soon as the smallest amount of dirty water gathers inside the panel.
BMW know all about this.  They even have a service bulletin that describes the problem and the easy fix.... drilling a hole too allow the water out of the drain plug. See service bulletin B513116 .
To check, I carefully unattached the undertray, and whilst videoing I pulled out my drain plug..... And gallons of rusty coloured water flowed out.
The dealership have now taken a look for £125 too diagnose the issue even though we knew the cause, plus charged another large sum as they couldn't lower the roof - (although the roof lowered OK for me just before I took it in as I cleaned and lubricated the seals with Gummipflege as I've always done) and they have agreed the window regulator has totally rusted out.  Who knows what condition the inside of the panel is in.
I bought the car from Ocean BMW, and have bought extended warranty every year since the main warranty ran out. The car has been serviced and maintained by Ocean BMW since new. I'm told the extended warranty won't cover it as the window regulator is damaged by water. And BMW HQ have refused to help out despite being told that I'm aware the water damage was caused by the drain blocked by the bad design of the undertray. The dealer say they are only a franchise and can do no more.
Needless to say, I'm not happy.
I would like to hear from anyone who has had similar issues with the blocked drain.. and whether it was fixed under warranty, extended warranty, BMW goodwill.... or, like they're telling me, passed on as tough luck on the customer.

[Greydog]

Morning Clive

Welcome to the Forum

Have you been in touch with BMW UK ? Dealers can vary massively in their approach and attitude with an issue like this.

I would take some advice on where you stand with the Sale of Goods Act and Consumer Rights amendments. As you have clear Internet evidence that this is a well know issue plus your own video of you draining water from your car, I would write to BMW UK (attaching all links to video) with a copy sent to the MD of your dealership (if you haven't already) I would ask for a time line for BMW/Ocean to resolve the issue to your satisfaction as it is a well documented problem supported by a service bulletin. 

Good Luck and keep us posted

Dave 

[Gadgetman20]

Thanks Dave.

That's great advice. I thought the dealer was communicating back and forth with BMW in Germany but after reading your comment I'm not sure. The dealer told me that BMW HQ were rejecting helping out with the issue. They also told me that my BMW Comprehensive Extended Warranty wouldn't cover the window regulator because it's badly rusted out due to water.

To me the service bulletin openly shows that there is a definite design issue. It demonstrates a simple way of improving drainage which then goes on to say can cause damage to the internal electrics. They even say that this damage is claimable under manufacturers warranty... so in early years before there is any likelihood of the window seals perishing or anything. That shows they know the drainage design is not good by default.

Therefore, why should the BMW extended warranty not pay out to cover the window regulators which would normally be a covered item?

The drain plugs and the undertray are not broken in any way. They are working in the manner as originally designed so water damage to the regulator is not caused by a secondary, non covered fault... it's caused by the basic design which they admit in the service bulletin!

Thanks again for your advice. I'll definitely be following that course of action.

Cheers