Not strictly a FixItWorkshop blog article really, but hey! It’s a cheap fix.
My beloved 2003 Boxster developed puddles in the umbrella holder on the passenger side (RHD car) when it rained hard.
The window was adjusted correctly and the door aligned properly, but when it rained, water ran down near the door mirror, under the seal, down the door card and in to the umbrella holder area. Water leaks like this, especially on the passenger side (RHD car) are a real problem on the Boxster, since the cars’ ECU is mounted on the floor on that side and is big £££ to replace/ repair if it fails.
Seemingly, the door seal rubber on the car adjacent to the door mirror area had worn and become slightly porous and was allowing water to get in between the glass and seal.
New door seals are very expensive and to prove the issue, I applied a small trace of tap (faucet) silicone grease to the area to restore the wax-like finish, the seal should have to seal properly.
This has fixed the problem for now. The door seal is worn and will need replacing in the long-term, but for now, this is a very cheap fix.