This car has spent its entire life stored outdoors. I got some water in the rear and onto the back seat after a heavy rainfall so I started resealing and checking the usually suspected seals and

• cleared one very clogged rear driver's side roof drain (super easy),
• installed a new antenna seal (ebay, same kit ECS Tuning sells but for way less, but OEM antenna didn't fit so had to use stubby antenna that came with kit, PLUS RTV sealant It will never leak!),
• rear brake light seals looked fine, just added some silicon paste for better stiction,
• added some silicon paste to the o-ring that seals the wire/connector as it passes through the hatch for the rear chrome piece with the button for trunk release.
• wasted a whole bunch of time on the rear window trim thinking it could be a cause...its not. No water can get in behind the trim.

the antenna:



The old seal/cover:










I mistakenly took the rear chrome trim off looking for water access via the rear glass and chrome trim (BIG MISTAKE!!!...no water can get in there) and I broke the plastic holder on one side. Its VERY hard to get that molding back on. It needs to be slid off the glass and needs prodigious WD40 lubricant to do so and things break in the process caused you know BMW LOVES cheap plastic.









I also decided to replace the rubber seal around the panoramic roof with an OEM seal. Honestly I do not think its was worth the trouble, but if you're so inclined...you'll need a regular razor blade, plastic razor blades and adhesive remover of your choice (I used Good Off) cause that thing is stuck on with some sort of heavy duty caulk integrated into the new seal (must be a Japanese seal cause its way too good a quality to be BMW...ha). Takes hours to get caulk/glue off and down to paint for the new seal.



The old seal delaminated in front corner after 17 years.



The new BMW seal..very expensive!



The old seal pulled off. You may want to heat the old seal with a hair dryer to get the adhesive caulk soft, it might pull off more completely. Maybe.



Plastic razor blade worked so so.



A regular razor blade works like champ but its easy to scratch off paint. Be careful.



New seal going on.



They sell you and extra 8-9 inches so you need to trim.



New seal in place...just make it flush with top of roof. It wont adhere immediately so you can pull it off and reposition until perfect.



Make the seam (make the ends meet) at the antenna, like from factory.


You need to remove the roof glass panels. SUPER EASY. I posted on how to do this in a shade repair thread.

old (left) 17 year old vs new (right with red stripe) :