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Topic: Internal Water Leak (Read 2026 times) previous topic - next topic

Internal Water Leak

Hi guys, I think this is the correct place to put this (apologies if not), I have water coming into my 1991, 5 door with sunroof. Originally I thought it was coming in from the rear, stripped the carpet out from the floor of the passenger footwell as I found puddles of water there, but couldn't see anywhere it could be coming in from, The only thing I could see is that where the seal along the bottom of the rear doors sits, they are quite rusty. I thought the front was dry, I thought the footwells in the front were dry, I had a quick closer inspection yesterday and was damp so lifted the carpet and found what is pictured below stuck down with some heavy duty sealant or glue on both the driver and passenger front footwell, not sure what it is hiding or what it is doing, I don't know if it is part of the cause of the issue or not, but I have hunch for some reason that it might be.

I have poured water down all 4 sunroof drains, using a small plastic can and funnel, they all seem to be draining fine, I then dashed some water using a plastic can across the sunroof, no difference. I dashed some water across all doors (one of the rear passenger doors seemed to have a larger gap then the other) no difference, I tried pouring water across the bottom of the windscreen, and the scuttle (both with bonnet open and closed), but hasn't seemed to make a difference. I will get a hose out at some point, but I think removing the carpet completely will be required for a better diagnosis.

If anyone could advise on where they think it could be coming from (It's not the heater matrix, coolant level doesn't drop and it's water not coolant coming into the car), and what these panels around the floor are,  and whether they are also part of the cause.

 

Re: Internal Water Leak

Reply #1 –
Hi there . The silver pads stuck to the car are just some after market sound deadening type pads a previous owner would have fitted to quiten down cabin noise a little .

I’m also chasing leaks in one of my mk2s at the minute. I would recommend fully removing interior and all the door cards then sit in the car whilst someone gets the hose pipe all over the car .

For me all 4 door membranes ( seals behind the door cards ) were leaking .
Also the rear washer jet was miss fitted and water coming in there . Also rear light foam seals and a few of the grommets for the rear badges were missing .

I’ve also got a leak from the sunroof. I won’t fit any interior back in until I’m sure they are all gone . Good luck

Re: Internal Water Leak

Reply #2 –
Hi there thanks for the the reply, good news it's not anything to worry about, thought someone had done some bodging for a second. There is potentially an issue with the rear foot well, not my main concern yet. Although I haven't got a hose out I thought half a litre or so of water across every door would show something. I don't quite understand how that membrane prevents water ingress into the car, as wouldn't the door just fill up with water, rather than the footwells, plus I don't think it's the boot as the boot seems okay.

Re: Internal Water Leak

Reply #3 –
That’s ok mate .
Pop the rear door cards off as it’s really easy and you will probably be able to see if the membrane has failed .

The membrane prevents water from entering the inside of the car and keeps any water running through the door and out the drain holes in the bottom of the door.

If the membrane has been disturbed or failed water will then leak down the inside of the door and over the rubber door shut seal and into the footwell . I could literally see all this with the door card removed .

My membranes had just become un stuck in places over time

Re: Internal Water Leak

Reply #4 –
Thanks for the reply, that's interesting with newer cars from like mid 2000's onwards, it must not have such an important job as, people try not to tear them when removing, but don't seem to be super meticulous when putting them back in.

Mine doesn't but I do wonder how it would work with models fitted with electric motors, as surely if the water just runs down the inside of the door, would it not corrode, or possibly short out the electric motor or wiring harness?

I do know for a fact the drivers side front has been partially removed before, as when I did the same to have a look at the regulator, there was a sign it had been removed partially in the past.

Going by what you have said then, that might explain why where the bottom of the door shut seal sits on the body, is corroded somewhat.

The jobs are mounting up thick and fast, I have suspicion that the previous owner possibly new about the water leak, as was stored in their garage, where it literally just fit. One cannot speculate though, however it's a shame some people aren't more honest especially when selling cars of this age, as it could be that "dream" of someone's which it was for me, and some people aren't lucky enough to be blessed with time, funds or space to upkeep such a vehicle. With the other jobs I have planned, I will have to recuperate some funds, before purchasing further parts.

Re: Internal Water Leak

Reply #5 –
My Son’s Mk2 we are in a similar situation.  He’s stripped the interior- but looking at this I will suggest a hose pipe; we now suspect the front windscreen. 
National Meet - 18-20 July 2025 @ Curborough Sprint Course

Re: Internal Water Leak

Reply #6 –
Without doubt in my mind its the door membranes. The shape of the doors channels water down the window and onto the door cards then into the car. Easy fix new liners are available and double sided tape. I know some people use thick plastic bags held on with double sided tape. 

Re: Internal Water Leak

Reply #7 –
Thanks for your reply! I will take a look when I get a chance, I feel like I need speak to a specialist to understand why if water runs inside the door, why it doesn't corrode or short out the electrics.

Re: Internal Water Leak

Reply #8 –
The electrics will be shielded and aren't in contact with the door where the water drips. The door probably won't rust due to the water being able to exit into the car and the anti corrosion fluid from the factory.

Re: Internal Water Leak

Reply #9 –
This one is always worth a read when it comes to water leaks.
https://www.vwgolfmk2.co.uk/clubforum/index.php?topic=136.msg309#msg309
There are a number of ways it can get it. I still have an unsolved issue in mine in really bad weather. It appeared to be temporarily fixed after having a replacement windscreen.

Re: Internal Water Leak

Reply #10 –
Also worth varnishing the back of the door cards when you get them off. They are only pressed cardboard so get in a right mess when wet. This will add an extra waterproof layer to them as well as adding strength and support. You can reinforce them with if you need to, I think @Monkey posted about the recently, using fibreglass.

Re: Internal Water Leak

Reply #11 –
i had the same problem. it got better after i replaced the seal
of the blower motor fresh air intake (number 4 in @vw-widow's post).

it is opposite to the ecu in the motor compartment.

Re: Internal Water Leak

Reply #12 –
Quote from: scs on
Without doubt in my mind its the door membranes. The shape of the doors channels water down the window and onto the door cards then into the car. Easy fix new liners are available and double sided tape. I know some people use thick plastic bags held on with double sided tape. 

I removed the front carpet yesterday and some of the standard sound deadening across the top of the transmission tunnel, it was raining yesterday, and could see immediately water pouring in from the nearside rear door membrane, oddly the others seemed to be fine, I haven't removed the door cards from yet, I will get a hose to be sure, but the front passenger footwell below the kick panel where the factory sound deadening is soaked at the bottom, and the drivers front footwell is moist and the foam and carpet were also wet. Now since I have owned the car it has been parked on a flat service, so I can't quite see why the front would be wet, when I picked it up from the previous owner the car was in a garage, I believe it was on a slope, and if so I cannot be sure in which direction it was facing. So unless one of the other membranes is leak not so badly, or somehow the water has just travelled around. I have reason to believe it has been leaking for some time, as where the door shut seal sits at the bottom, the metal is quite rusty. I have only owned the car for 2-3 years.

Re: Internal Water Leak

Reply #13 –
Sounds like you’re getting there . Problem with water leaks is the smallest of leaks can travel all around the car . Down cables , wires. Panel edges etc . Also carpets and sound deadening soak up water like a sponge and that can throw you in the wrong direction.
My routine has always been .
1) strip all interior , door cards carpet and underlays etc .
2) on a dry day once car is dry inside get inside the car , then have your mate hose the car down .
3) locate the leaks , often there is more than one . Then Fix the leaks .
4 ) refit drivers seat . Use the car a bit , wash it etc , leave it in the rain .
5) once I’m confident all leaks are fixed and only then will I refit the interior.

I do appreciate me having the use of more than one car helps me be able to do this .

Re: Internal Water Leak

Reply #14 –
Hey, thanks for the reply!

Yeah my other car seems to be a oil contaminator at the minute (fresh oil goes in, used oil leaks out), I have some jobs planned for it to see if they solve anything), but I only need to use my car once a week for a 400 mile round trip so not too bad, I have managed to strip the carpet out of the passenger compartment (have left the boot as that seems fine) refitted all seats.

I have managed to track down 3 leaks into my car, both rear door membranes, I also think the offside front is also leaking, but will have a second look tomorrow, I removed the nearside rear completely as in the rain yesterday, it was pouring in. I have left the others fitted for the minute.

There is also a leak on` the nearside front, not from the membrane, it looks like water's coming in from the front wing, I have checked as best I can round where the blower motor sits but that all looks dry. Somehow water is dripping from the sound deadening where it's attached to the inside of the front wing, in front of where the door closes, and drips onto the floor.

I tried spraying water down the aerial, as where the aerial pokes through the rubber, there is a seemingly large gap. This hasn't seemed to make much difference.

I will continue the search tomorrow, I wanted to remove the housing/vent on the inside where the blower motor sits so I could remove the sound deadening without tearing completely, but some of the metal spring clips seem impossible to get to, there is one that is located on top of the housing and there doesn't seem to be a way of getting a screwdriver or trim tool in, to pop it off, slightly frustrating to be honest.