A 2008 VW Tiguan full of water -- front footwells, boot, both sides. A garage had already tried to fix it and failed. Four sunroof drain pipes: the front two had shrunk and were leaking through the A-pillars into the footwells; the rear two were disconnected. One just fell out when touched -- someone had been up there before. Airbag terminal sitting in water with visible corrosion.
A 2008 VW Tiguan that came to us full of water -- front footwells on both sides, boot full, terrible smell, rear door not working from outside. A garage had already attempted to fix it and failed. The car filled straight back up again after their repair. This is why.
How Sunroof Drains Fail -- and Why Garages Miss It
The VW Tiguan has a large panoramic sunroof with four drain pipes -- two at the front running down the A-pillars, two at the rear. Over time, these silicone pipes shrink. When they shrink enough, they pull off their connection points at the sunroof cassette. Water that should drain away outside the car instead drips into the headlining cavity, runs down the A-pillars, and floods the footwells. The rear pipes drain into a box section in the C-pillar; when those disconnect, the box fills and overflows into the boot area.
The previous garage had spotted this and tried to seal the connections with sealant rather than replace the pipes. On camera the old pipes were inspected before disposal: you can see the sealant around the joints. It had not worked -- the connections were not secure and the water kept coming in. When the pipes had already shrunk and the joints are no longer flush, sealant is not the right fix. Replacement pipes are.
What the Inspection Found
Both front footwells wet -- passenger side visibly, driver's side confirmed with the moisture detector (no visible water but the sensor went off immediately). Boot: standing water. Rear passenger seat area: wet under the trim panel, an inch deep across the full width of the box section.
With the carpet lifted: airbag control terminals sitting in the standing water, with visible corrosion already forming on one plug. Warning lights had not appeared yet -- "probably yet to come." We treated the connector with contact cleaner. This is exactly why you do not leave water in a car: the safety electronics corrode silently before the warning light shows.
One more find: when the rear sunroof pipes were removed, the mirror cable on the driver's side just fell out from behind the headlining. It had not been clipped back in. Someone had been up behind that headlining before, and it was not reconnected properly. The rear door not working from outside may have been connected to the same previous access.
The Fix
All four sunroof drain pipes replaced with new. The cassette cleaned before the new pipes went in -- mould spores going down brand-new pipes would defeat the purpose. Both A-pillar pipes re-routed and clipped correctly. Both rear pipes reconnected to the cassette and secured. Mirror cable reconnected. Floor pan dried to bone dry using the industrial drying rig with pipes running under the carpet.
The whole interior was OdourKilled -- UV fogged -- to deal with the smell that had built up while the car was wet. The front bumper had some scuffs; Matt the smart repair man came in on Saturday and resprayed the affected area for £195.
Why the Garage Failed
A local garage can find an obvious leak point and apply a fix. What they typically cannot do is test whether that fix worked under simulated rain conditions, check all four drain points systematically, or deal with the water that is already in the car after the leak is repaired. Getting the car dry and decontaminated is a different job from finding and fixing the leak -- it requires different equipment and it takes time. Most garages are not set up for it.
See our water leak diagnosis and repair service and carpet drying service.
Share this video