4 Series Convertible - water collection in sills issue !

[Julian Pasiut]

Hi all,

I have owned my 420D convertible for almost two years now and I am really pleased with her combination of performance and economy. However, two months ago I had trouble lowering the rear nearside window - it would not glide down smoothly but only operated in repeated pressing of the window winder button. Even when fully down I found the retractable roof would not fully open. My local BMW specialist garage advised that the problem was that the window winder mechanism on the nearside had failed due to being 'wetted-out' by water ingress to the sill from normal rainfall/washing. Apparently the sill does not have a means of draining away on the 4 Series convertible and eventually it 'floods' the window winder mechanism which sits in this area. My garage stated that this is a common problem on the convertible and they have rectified many of these cars by making a simple drain themselves. I paid £600 for the new winder and labour so was not happy but imagine my horror to experience the offside 'fail' as well !

I have now paid out @£1200 to deal with a 'common knowledge' issue that should have been subject of a simple recall to rectify. 

I have started an investigation with BMW UK and my local BMW Stratstone dealer to investigate this issue with a view to receiving some recompence for an obvious design fault.

My question is, are there any other people/garages 'out there' who have experienced this issue with the 4 Series convertible so that we may form a group to petition BMW for financial retribution ? (I have noted several comments/pictures/videos on Google and Youtube so I know I am not the only one !!).

Please feel free to contact me via this post or via my email at [email protected]

Thank you !!!  

[Mike Cullwick]

Hi. Having read so many articles from BM convertible owners, it is appalling that BMW fails to recognise and this fault through a recall? Do you know where the water enters the sills/ boot area? Can the point of entry be identified? Does the sill fill up before entering the motors etc? I ask because I noticed water escaping from the rear , near side sill area after a car wash and therefore want to solve the issue before it reaches the stage of such expense that you have had. Any help ideas welcome. 

[Julian Pasiut]

Hi Mike,

Thank you for responding.

Unfortunately you have been the only person to respond to my shout out concerning this problem - Im starting to think this is just me that this has happened to or that anybody else just gets on with it without complaining !

In answer to your queries, I believe the water ingress happens with natural rain/water hose falling on the car and seeping down the rubbers of the top canopy/windows...they are not impervious to water and in most other cars it is directed away from collection. Unfortunatelly the 4 series convertible was made without a means of sufficient drainage and eventually it causes a flooding/failure of the said window winder mechanism.

My advice would be to go to your local BMW garage or specialist BMW service garage and get advice/action to deal with this problem before it gets expensive and have no recompense from BMW !!

Please let me know how you get on and what you are told/advised by the garages involved.

Cheers for now,

Julian

 

[Professor80]

Hi: There is a detailed article on facebook dealing with this problem. It requires removing the outer cover of the door sill (water may pour out) and notching it to match the actual drain hole in the sill. Simple solution. Don't understand why BMW hasn't notched the sills at the factory! I have a 2021 430i convertible and don't know if my car has the same problem. I have to lay down on the ground and check. The sill cover notch has to line up with the drain in the sill.