Where's the water coming from?

Acousticplayer

Zorg Addict
Joined
Dec 8, 2011
Points
60
Location
Leicester England
Model of Z
2.8
Hi everybody. 1998/9 2.8 roadster. Upon taking the drivers seat out to sort out the rocking seat problem,I find there are puddles of water under the carpet. The rubber foam is literally soaked. Not sure whether the passenger side is the same as not removed that seat yet.. Any suggestions as to the point of ingress?

Thanks.
 

ktnez99

Zorg Guru (IV)
British Zeds
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May 18, 2018
Points
164
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West Midlands
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Z3 2.8L
The leak maybe from the front pillars letting water in. I’m assuming the window is closing fully?
 

John_B

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British Zeds
The M44 Massive
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Jun 2, 2023
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Derbyshire, UK
Model of Z
Z3 2.8 pre-facelift (Izzy)
There are about 5 or 6 common water ingress routes;

Heater matrix (under the scuttle panel)
Door seals
Window seals
A-pillar
Roof drains
Even around the boot.

The best thing I did was strip my interior, take out the carpets and then sit in the car while my wife sprayed it with the hose and I looked for drips.
 

Acousticplayer

Zorg Addict
Joined
Dec 8, 2011
Points
60
Location
Leicester England
Model of Z
2.8
Hi. Thanks for your replies. I don't think this is a problem with window or door seals. Nor the roof or A pillar. There is no sign of any water contamination apart from under the carpet. The carpet itself is not wet apart from the rubber foam underneath. Nor does the water extend beyond the raised cross member on the floor . To me this suggests the water is entering from the rear ,going under the carpet, and building up against the raised cross member.

I see entry around the boot can be a problem.

Can anybody explain the route of ingress and is it even possible for a build up of water in the boot can find it's way under the carpet in the driver area.

Thanks.
 

Duncodin

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Pontrhydyrun - in Crow Valley
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If you look behind the seat right in fhe corner behind the B pillars where the softtop hinges. You'll see an open topped metal box. This box catches water that runs down the back of the roof and round the sides into the corners behind the B pillar. There's drain holes in there. I suppose if they were blocked then water would overflow and end up on the floor where you said.

But don't ignore the other suggestions. That floor cross member you mentioned will not prevent water running front to rear.
 

Acousticplayer

Zorg Addict
Joined
Dec 8, 2011
Points
60
Location
Leicester England
Model of Z
2.8
Hi Duncodin. Thanks for that. I see what I think you are referring to. I imagine it's difficult to get to the drain holes,do you know where the exit is for the water, presumably somewhere under the car.?
 

Duncodin

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Pontrhydyrun - in Crow Valley
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Hi Duncodin. Thanks for that. I see what I think you are referring to. I imagine it's difficult to get to the drain holes,do you know where the exit is for the water, presumably somewhere under the car.?
If I remember rightly it just exits between the inner and outer body panels so not accessible from below. So it's not a nice tube exiting under the car. It just tips out from below the sill.

First I'd pore a little water in there see if it drips out the bottom onto the floor.
 
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Oddly Godly

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British Zeds
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May 17, 2019
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dunstable
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z3 2.8
Mine had an A pillar leak and the membrane behind the door panel was ripped. If you pour water on to the door windows check that any water that enters the door leaves on the outside of the door and not the inside. I also had a leak on the passenger side after autoglass fitted my windscreen incorrectly.
 

Mal315r

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Apr 15, 2025
Points
3
I had a leak which entered the car passenger door side, carpet and under foam was drenched, I had to cut the carpet bucket out and remove foam and treat rusted areas. The cause was when it rains it enters inside the door and relies on a flimsy membrane to ensure rain exits at the bottom of the door drain hole. Solution, take the door card off and look for any Tares on the membrane, i fixed mine with some strong rubber adhesive tape. Pour water onto side of window and it should exit at the front of the bottom of the door. Fit door card back on. Hopefully this is the fix for you. To add if you open the door the drain hole is on the bottom corner of the door, you will see water coming out if you pour water on the outer door window.
 
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TriumphZ3

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Aug 2, 2023
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66
For some strange reason I was able to trace my serious and extensive water leak to the A-post where the hood seals. The photo shows the results of one rain shower. :eek: The foam under the passenger-side carpet was a lake, gallons of water under the carpet which took ages to dry out. I cleaned out the drain channels with stainless cables right the way down to inside the front wings then sealed the joint with a shaped bicycle repair patch. Perfect ever since and very simple to do.
DSCF2474.JPG
 

Pingu

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Dec 8, 2011
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The carpet is a massive sponge. You cannot dry it out in situ, and it's a bi*** to remove. Best technique is a Stanley knife up the centre after removing the centre console.
 
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