Wet Seat Woes

During the pandemic, I've had some extra time to troubleshoot my C4S! This one is strange; recurring dampness in rear passenger side seat well. Quite wet actually but dries out soon enough in this heat. Seems to come from below. I noticed it when I removed the leather cushion. Any likely culprits. All other carpets seem dry and there's no obvious ingress from the inside at least. Thanks, DJ911

Drain behind the rear side panel. Take the front of the rear wheel liner off and you'll see the blocked drain hole. More here: http://www.911uk.com/viewtopic.php?p=1119818 Looks like this:

Great, thanks very much, I'll try that.

I have been chasing similar but probably worse than you are experiencing. When I bought the car it kept getting steamed up so did some investigation and drivers side rear football was wet, didn't seem to dry out so pulled it up and soaked underneath. Over couple of weeks kept putting a towel under carpet to dry it out and seemed OK. Assumed sun roof drains and did some picking around with stringer wire. Everything seemed to have dried out so all good but jet washed the other day and floor wet 😢 Was intending to take out door panels and rear seats to tidy up some scuffs and treat the leather so thought I'd dive in. By this time foot well was dry but only when removing seat pads did I realise it was wet under there. Stripped everything out and then opened sun roof to pour some water in channels, came out of all 4 outlets no problem but also come out in rear corner by window under trim on both sides - confusing. So today out with C panel trim and headlining at back to check drain tubes, all connected. Took off and blew down and clear and just in case did compressed air. Tried pouring water again and for most part OK but with too much flow the water comes over the stop end of the channel where outlet is, going everywhere!! Looking at trim panels and roof lining its obviously been like it for years but luckily no serious damage or rust. I think the answer is that the drains can't take too much water flow, on many cars the seal round the sunroof opening is a dust/noise seal but looking at construction I think 996 it is a seal and mine is pretty flat. So think the old seal is allowing too much water through when jet washing (think rain ok based on watering can test) so will try a new seal. So as above, check drains first but should be able to check by seeing water comes out each corner initially. Will let you know when I get a new seal fitted what the outcome is...

OPs car is a cab and very different from the coupe.

in short .. pouring too much water into a sunroof with it open .. a targa roof with it open etc etc will over flow the drains and cause a leak .. This is not the actual fault though .. the drains are only so big and not designed to cope with a large amount of water that couldn't get in there with roof closed . please be aware that the rear glass rubbers can allow water into the car in this instance .. i had one about 2 months ago .. rear n/s/r glass rubber which is riveted had been replaced badley allowing water ingress . A proper water test which is what i do .. remove relevant panels to see the body work .. soak and i mean soak the car in water from different angles .. never upwards through .. water test must be done as in the way water would normally fall on the car . you then look to see where its coming in from .. 10 mins min . 20 is better .

Sounds like you've sussed this one, good luck with it and let us know how you get on. I feel a bit guilty for initially accusing my children of spilling their water in the back.. I couldn't for the life of me account for any other explanation!!

Oops didn't see that ! And new one for me as didn't realise you could get an S in Cab option.

Thank you and seems to have confirmed where I am at the moment with this....

...[/quote] Sounds like you've sussed this one, good luck with it and let us know how you get on. I feel a bit guilty for initially accusing my children of spilling their water in the back.. I couldn't for the life of me account for any other explanation!![/quote] Thanks, not gonna let this one beat me 😁

Check the end of the tube that runs down the c-pillar. The flexi pipe joins to a nylon end with a 90 bend which then pushes into the outlet grommet in the wheel arch. I found on my car, there was a leak where the flexi pipe joined the nylon end piece. Test it by pulling it out of the wheel arch and putting your finger over the outlet, and pour some water into the sunroof drain channel, and check if the pipe leaks. Therefore on mine, whilst some water drained out properly, some drained inside the car in that back corner. From there it can run forward to behind the rear seat, and soak into the foam all the way down to the rear seat well. Getting the carpet up in the rear is hard work.

Got this job done today. The usual fun with removing rusted torx screws! Put some new speed nuts and screws in afterwards. The drain plug was quite bunged up with matter, not sure if it was draining or not, but gave it a good clean. Fingers' crossed it sorts the wet seat issue! Thanks again for the tip.