Can someone point me in the right direction as to where the sunroof drain holes are on my 2013 A3. It’s the tilt and slide version. I’ve looked on google but can’t seem to find anything. Any pics would be great.   Thanks. 

Edited October 31, 2025Oct 31 by waynem

I don’t know specifically about A3, but I do know about A4 panoramic. I suspect the A3 will have two front drain holes in the internal cassette that exit just below the front door hinges. At the rear, again they may not be visible, but should exit at rear wheels behind inner wheel arch liner.

If you open sunroof, you should be able to see the front drain holes. Be careful about running anything through them if trying to clean them. The drain tubes connect to a sunroof cassette via rubber grommet connection. You can run strimmer nylon line through it or compressed air via a smaller length of rubber tube.

It’s a misconception that sunroofs provide watertight seal. They do not, the weather strip on the glass will provide some protection, but water that passes between the sunroof glass and the cassette underneath should drain out.

The front A pillar trim in the car is plastic and covered with fabric, so you don’t realise there’s a leak until you notice condensation on windows or wet carpets. Underneath this trim will no doubt be curtain airbags.

If you’re working in car, disconnect battery (put on trickle charge) and leave for 30 mins before you start work. There should be, if similar to A4 of this vintage, Torx screws behind airbag badges. You’ll also need to partially remove rubber door seal to a point, and internal sun visors, grab handles and roof controls. You’ll need special tool for grab handles.

In my experience on A4, then it’s rarely the sunroof drains, but a manufacturing fault on the cassette. On A4 it was made by Webasto, so suspect A3 could be similar. The plastic and aluminium cassette is sandwiched with a sealant that fails.

I can understand the urgency to repair. Audi would normally replace the cassette, if that’s what’s at fault, but you’re talking thousands to strip, remove and replace. They would do water test with most of interior trim removed and headliner dropped, before committing to repair.

See what you find and come back to me and we can go from there on any repair if the cassette is leaking.

Edited November 1, 2025Nov 1 by spartacus 68

On 11/1/2025 at 6:51 AM, spartacus 68 said:

I don’t know specifically about A3, but I do know about A4 panoramic. I suspect the A3 will have two front drain holes in the internal cassette that exit just below the front door hinges. At the rear, again they may not be visible, but should exit at rear wheels behind inner wheel arch liner.

If you open sunroof, you should be able to see the front drain holes. Be careful about running anything through them if trying to clean them. The drain tubes connect to a sunroof cassette via rubber grommet connection. You can run strimmer nylon line through it or compressed air via a smaller length of rubber tube.

It’s a misconception that sunroofs provide watertight seal. They do not, the weather strip on the glass will provide some protection, but water that passes between the sunroof glass and the cassette underneath should drain out.

The front A pillar trim in the car is plastic and covered with fabric, so you don’t realise there’s a leak until you notice condensation on windows or wet carpets. Underneath this trim will no doubt be curtain airbags.

If you’re working in car, disconnect battery (put on trickle charge) and leave for 30 mins before you start work. There should be, if similar to A4 of this vintage, Torx screws behind airbag badges. You’ll also need to partially remove rubber door seal to a point, and internal sun visors, grab handles and roof controls. You’ll need special tool for grab handles.

In my experience on A4, then it’s rarely the sunroof drains, but a manufacturing fault on the cassette. On A4 it was made by Webasto, so suspect A3 could be similar. The plastic and aluminium cassette is sandwiched with a sealant that fails.

I can understand the urgency to repair. Audi would normally replace the cassette, if that’s what’s at fault, but you’re talking thousands to strip, remove and replace. They would do water test with most of interior trim removed and headliner dropped, before committing to repair.

See what you find and come back to me and we can go from there on any repair if the cassette is leaking.

I’ve tested the drain holes and they seem clear. So not them.