I parked outdoors for a change on a trip to Lapland. It was raining rather heavily and I noticed water dripping into passenger footwell. The car had been sitting for an hour at that point and it definitely isn't condensation from AC or coolant (yes, I tasted it). The point of the leak is right behind the glovebox near the firewall.

I haven't looked into the subject yet but does anyone have good pointers, ie. known weak points and causes for something like this? Sunroof water drain? HVAC water drain? Anything?

Thanks.

 

Hello @hq_ ,
Being that you mentioned "sunroof", I take it you have a Flying Spur, Mulsanne, or Bentayga, if Flying Spur, I would first check the cowl area for proper drainage first, you can remove the bonnet seal gasket that runs along the cowl area cover, turn the retainer fasteners, and gently lift the cowl cover slightly to inspect for water pooling, even take a garden hose to add water to the area to check for proper drainage, the water should drain over the transmission at the center of the vehicle, to fully remove the cowl cover, you will need to remove the windshield wiper arms, next I would open the sunroof and hand pour a pitcher of water into the passenger side front portion of the sunroof drainage / pool area built into the sunroof assembly, to be sure that the water makes it to the ground, be it in the door jam area, the wheel well, or even into the cowl area, I just cannot recall at this moment where the FS front sunroof drains to, my A8L is the door jams iirc.

I understand that it is not your HVAC drainage at this time, but it would be great preventive maintenance to inspect and clean them also.

See the attached video for the cowl drain under the HVAC suitcase.


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Center Cowl Drainage Flap, as seen from the underside with engine removed.


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HVAC Drainage Tube 90°.


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COWL DRAIN LOCATION AT TOP. LEFT AND RIGHT HVAC DRAIN TUBES.


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SAME, HVAC TUBES.
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HVAC DRAIN BLOCKAGE. THIS IS WHERE THE 90° TUBES HOOK UP LEFT AND RIGHT.


Johnny

 

Thanks, Johnny! This is great information. The car is a '09 FS. I'll have to dig into this during next few days, it's really annoying and might result in long-term damage unless dealt with properly.