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Dear Sir, I can’t get to the bottom of a water ingress issue in my 996 Turbo (Coupe). When I get inside the car after periods of rain it smells damp. I’ve felt water drips alongside the underneath of the passenger door (the door card itself appears dry). The membrane appears to be fine. The door drains have also been checked and they’re clear, and the window height has also been reset. What else could it be? I do hear a faint whistling coming from the passenger side when driving along, so I wonder if it could be linked?
George Mcgowan
A water leak is always a tricky one, especially if the common culprits have been addressed.
The door membranes are the cause of 95 per cent of the leaks from the door panel area. Typically, the glue becomes hard and unbonds over time. Alternatively, it’s possible that the membranes weren’t renewed at the same time as foot lock module replacements or window regulator replacements.
The membranes are sensitive and even when brand new from Porsche the glue can still sometimes not be as tacky as it should be. Heat is required to soften the glue prior to installing. In addition, when removing the existing membrane the old glue residue is a nightmare. It’s a time-consuming job to clean off, and if rushed and not fully clean can create issues with the new membrane adhering correctly.
Another possibility on the door are two upper grommets for the window adjustment. It’s common for people to remove and never refit them, resulting in an area where water can enter.
I think in your case the obvious culprits have been addressed/checked. So my best advice would be to remove the interior door panel so just the membrane is exposed. This provides an opportunity to inspect it for areas in case it’s become unstuck, but also enables you to carry out a water test with a hose to simulate rain. Then, over a course of 10-minute intervals, carry out checks from the driver’s side to see if you can locate the source of the drips.
It can be a time-consuming operation, but it’s worth doing if you’re determined to solve this annoying water problem.