Trying to sort out cabin leaks

My new car leaks like a sieve, see the picture below!!
I’m going to try and address the problems this coming weekend so, if anyone had any top tips, please let me know!
I have a ripped rear screen but I doubt that is the main cause but, as I’m going to take the rear screen out to send away to get repaired, I’m going to use it as an opportunity to take the whole roof assembly, seats and carpets out so I can get to the bottom of it. I’ve read that there are a couple of drain holes that can get blocked but, anywhere else I should direct my attention?

Vinyl soft tops shrink over the years and pull back above the door windows. If you can easily see the rubber seals on the frame above it’s probably quite shrunk already. When drops of rain can curl underneath and drip onto the rubber seals, the seals fill up and overflow into the car. You can temporarily improve things by putting something greasy like silicone oil on the edge of the roof so it sheds drops better, but proper repair means a new soft top.

The drains you’ve heard about are on the rear shelf behind the seatbelt towers.

When rain runs down the back window, it next runs around to just behind the doors and then drops inside the car. It collects in two shallow cups set into the rear shelf and they each have a drain tube which runs straight down and exits under the car just ahead of the back wheels. Those tubes block up with leaf mulch, so the cups overflow and water just pours into the sills.

You can clear the drains with some kind of flexible rod or brush but beware not to push so hard the tube disconnects from the cup. Beware also that, depending on the year, the tubes will likely have rubbery flaps a short way up from the bottom, to reduce road noise in the cabin, but that makes them more likely to clog up with mulch in the first place.

If the rear sill drains are that blocked that the front floor pan floods, then behind the seats will be waterlogged. Most likely the hood is either badly fitted or at the end of life.

I agree unless the car is on a steep slope or has major flooding behind the seat it is not the drains. But clean them anyway!
It looks like the passenger side, so I suggest checking the scuttle drain next to the heater air intake, where the water should run off into the nearside wing. If that is blocked, water can overflow in to the cabin, especially if parked on a roadside.
As a very temporary fix, try parking drivers side to the kerb.

I take it that’s simple enough to locate on the passenger bulkhead?

I spent an hour on the car this afternoon and I think it’s fairly simple to see what the issue was, both drainage holes were badly bumped up and it took ages to gently work them free and flush out.
As the water ingress was so bad, I’ve whipped the seats out to remove the carpet and I’ll valet them and then dry them out before refitting so I’ll have a nice clean interior and while I was on a roll, the roof came off so I can get the rear screen repaired!

My word your day was productive.
It might be worth checking the drain holes under the sills with a cocktail stick? while you are drying things out.

I was unaware of any more drainage holes!
How many more does this car have?
I’ll see if I can locate those as well…

Those aren’t really drain holes, more like condensate relief holes, either side of the jacking points.

With that amount of water in the car, I’m surprised it didn’t smell a bit whiffy.

A local company near me Autotrim Ivybridge Devon use a Trombone cleaner to clean the drain holes. I now intend to have it done every October as I have had them blocked twice. Car is wet through inside.

I would also check the door membrane and speaker hole.
As for the drainage tray/tubes at this time of year they need checking every couple of weeks not every 12 months??? a simple trombone cleaner off the bay of e will do the job or the OE whip aerial, sill drains are easy done with a small phillips head driver or similar…

http://www.mazdamenders.net/forum/viewtopic.php?f=157&t=6346
M-m

Hi Martin, new member. Silly question, the road noise inside my Mk3 cabin is deafening so I reckon “those flaps” must be stuck open. Any idea how to close them please? Best wishes, Robert

I must admit I’m not familiar with the arrangement in a Mk.3 (maybe someone else can advise?) only a Mk.1 where the soft plastic drain tubes have discs of the same material fitted near the bottom where you can reach them

Thanks Martin, that was helpful. If this rain ever ends I will crawl under and have a feel around. All the very best. Robert

I’m still plodding in with this and due to the level of water that’s now inside the car, I’m going to taken the carpets out to drain the cabin area and clean it all up but, I’m guessing that the whole centre console has to come out to release the carpets?

To properly remove the carpet, the dashboard needs to come out. Most of us cut the carpet out from under the dash.

Once the drains are clear. Get some aquarium foam (used as a barrier to stop the fish getting into the filter) and simply plug the ends of the tubes with it. Water flows through but it stops the noise as it disturbs the air flow preventing it from causing the noise.

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So I take it you just remove the lower section of the dash with the stereo etc in and then cut under there?

Remove centre console (5 screws), remove tombstone with radio, and get in there to try and cut the carpet. Afterwards, you can tuck the carpet and be none the wiser (though I add some double sided tape).