Wet carpets or a musty smell in a GTI is almost always blocked water drainage, not a mystery leak — water that's meant to run out isn't.
Where it comes in:
- Blocked plenum/scuttle drains under the wipers — leaves clog them, water backs up into the cabin and the pollen-filter housing, then the footwell. The number-one cause.
- Sunroof drain tubes clogged — water runs down the A-pillar into the footwell instead of out.
- A perished door vapour barrier letting rain into the door.
The fix:
- Clear the scuttle/plenum drains and the pollen-filter housing — the common fix.
- Flush the sunroof drain tubes.
- Reseal the door vapour barrier if that's the path.
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