Just got back from two weeks away to find my golf completley filled with condensation. On closer inspection the back seats seem to be so wet that they have spots of mould on them !! I have checked the roof lining and thats dry but cant think of how only the base of the back seats can be wet? Any ideas on which seal isnt working ? There is also some dampness in behind the rear passenger light.

Macdaddy, I think you need to check the vent seals as circled in the photo below, they are very prone to perish

See how this one is knackered. It let loads of water in, and made my back seat bases very wet as per your findings. Also the spare wheel well was flooded

This is what you'll see from inside the car

So this is what I did to resolve it, lots of silicon. After I took this photo I went over it with another fat layer of silicon

and, touch wood, my car hasn't leaked since...

I will probably post this as a 'watch out' as not many people are aware of the potential leakage from this part of the car.

Hope it helps you sir

thats some garage Pat!

I know the answer's going to be "No", but I'll ask anyway.  Can you remove/replace the seals without removing the bumper?

Thanks, I'll check the spare wheel well and see if it has water in it.

Benjie mate, its not really possible to do this job without having the bumper off, sorry :o/

Gary, that's the place I work :oD - luckily if I need to do any jobs I can snaffle the keys ;o)

Not to worry, I'm having the bumper off in a few weeks to have it repaired after some of my shocking parking, so I might get them changed then - maybe a pre-emptive £££ saving measure?!  Any idea on part No's?  Or are these things available cheaper from other places?

Just bodge them both with silicon like I did, costs pence and to be honest you'll probably never need to remove the vents :o)

This problem also happened on my previous mk4 :o/

Great, thanks for your help/advice!

Pat, I seem to be having the same problem mine is only leaking on the passenger side. can you confirm the leaks happen even when the car is stationary.

Reason I ask is I dried out the small area beneath the flap last night and overnight there has been alot of rainfall and I checked this morning and the area beneath the flap was full of water.

 I have also replaced the gaskets seals on both rear light clusters and attempted to remove the bumper but failed dismally, managed to get the 4 bolts off 2 under the lights and the 2 underneath the bumper, also removed the 3 screws in each wheel arch but the bumper refused to budge.

 Are there anymore screws/bolts I have missed, or is there some sort of knack to getting the bumper off, brute force and ignorance does not seem to work!.

 

Thanks

 

triman:

Pat, I seem to be having the same problem mine is only leaking on the passenger side. can you confirm the leaks happen even when the car is stationary.

Reason I ask is I dried out the small area beneath the flap last night and overnight there has been alot of rainfall and I checked this morning and the area beneath the flap was full of water.

 I have also replaced the gaskets seals on both rear light clusters and attempted to remove the bumper but failed dismally, managed to get the 4 bolts off 2 under the lights and the 2 underneath the bumper, also removed the 3 screws in each wheel arch but the bumper refused to budge.

 Are there anymore screws/bolts I have missed, or is there some sort of knack to getting the bumper off, brute force and ignorance does not seem to work!.

 

Thanks

 

there should be four little black type clips inder the lights too! 2 each side. get a small screwdriver and put the middle of the clip, as it falls out the bottom and allows u to pull the clip out!

u may wanna also check your sunroof drains, if u have one, as they drain through those vents i think

Triman, hi mate yes it will leak when stationary.

You almost got all the fixings off, check also under the light clusters for the plastic split pin (1 per side) these need to be tapped downwards with a small screwdriver until the split pin falls out. You then remove the insert and the bumper will slide off. The split pins can be retrieved once the bumper is taken off.

Hope this helps you

This is great just what i needed I'm having the same problem at the moment. I went for a drive on a dry day ended up going down a road that had a water burst water pipe on it so it was like it was raining. couple days later i was in the boot an noticed it was wet lifted the floor an the water was half way up the spare wheel. now i know where the water is getting in cos it wasnt raining. or is there somewhere else it could be getting in from underneath?

Thanks for the info guys...never spotted those little split pin thingys...even had the exploded diaggram how to remove the rear bumper from VW and it did not show them on there!!!

Will give it another go and hopefully be alot more succesful and plug that leaking rubber gasket.

 

:-) 

Finally managed to get the rear bumper off, those 2 split pins were the problem!

Used the same sealant the windscreen guys use to stick in new front windscreens and put a good bead around both flap asseblies on both sides.

Just waiting for it to rain again to test there are no leaks, fingers crossed my boot will be dry again and I can put all the carpet and trim back in....
 

Thanks for all your help 

tazb 1.6:

This is great just what i needed I'm having the same problem at the moment. I went for a drive on a dry day ended up going down a road that had a water burst water pipe on it so it was like it was raining. couple days later i was in the boot an noticed it was wet lifted the floor an the water was half way up the spare wheel. now i know where the water is getting in cos it wasnt raining. or is there somewhere else it could be getting in from underneath?

Hmm, wonder if this could be my problem this vent, my spare wheel well looks like a swimming pool at times and creates condensation in the car when its got a lot of water in it, yes I know its winter, but honest, mop it out and dry the wheel and the condensations gone!  One more thing to check could be to check the the bungs in the floorpan under the spare wheel are still ok and not perished like mine were as changing them on mine has reduced the water intake a bit but not compleltly so I guess when it finally stops raining that it may well be bumper off and look at this vent things.

Thank God I was given the link to this page, seems like the problem I have.

wet spare wheel compartment & back passenger footwell.

Fingers crossed I can get off my arse & try to fix this :D

I still havent gotten the finger out an fixed it. I got as far as taking the floor out the boot to let it dry out in the house. seems to have stopped the tyre well filling with water must be lettin it evaporate instead.

Ive just hovered my car and noticed that the rear passenger foot well is soaking wet between the carpet and the floor mat (the top of the mat isn't wet!) After reading this post Ive checked the boot, the spare wheel well and the back seats but they're all dry. Do you think it could still be the same problem as above with the seals behind the bumper, or could it be leaking from somewhere else?

If it is has anyone got a link to a guide for removing the rear bumper, preferably with photos?

Thanks.

Good find this post, I seem to be experiencing the same problems with a swiming pool in the boot. Got my faither to hose the car down while I sat inside (all trim removed) and found it to be leaking from the N/S vent & the O/S brake light. Lucky me. Is it possible to buy & fit new seals DIY style or are you best to just whip out the tiger seal & bodge it up??

Just seal round them with bathroom sealent. Thats what I did when I had the problem and it solved them fine, infact I sealed round everything that could be sealed with me having the bumper off, just to make tripply sure.

this is a good guide thanks. i have a leak from near my passenger side rear light. only noticed when i had to take out sub this morning. good timing of the thread lol. cheers

Very useful guide, I followed the instructions to sort my leak from my vents. Only thing I would add is that the light fixings are different on L&R sides. Both have 3 nuts holding lens to bodywork. The RH light has a push fixing into a rubber grommet at it's forward lower (pointy) end, but if you remove the RH light first then the LH be aware that the front point end on the LH light is bolted - you can just get a socket through a hole in the inner panelling, behing the wiring loom. I was pulling it in the same way as the RH light, and probably lucky not to snap the corner. Guess what I am saying is that the bolt/nut positions on each light are not the same. Total time to remove lights, bumper, fix vents and reassemble maybe 1.5 hours. Thanks to all the previous posters.

 Good work for the write up Pat & others for comments!

Did this over the weekend.  Was a bit of a pain and one of the bolts on the top of the bumper sheared in half when I took it out - but it seems to be secure enough without it.  Might be a worthwhile noting that these seem to rust!

My seals looked OK to the eye but when I washed n dried it all off before sealing back up I noticed that they're actually porous and could be wrung out like a cloth.  Maybe this is just a sign of them being past it?

Whole vent system is a bit over-engineered in my humble opinion - little rubber flaps, flimsy plastic vanes, etc - but glad I took the trouble to do it.  Dry boot again!  

glad it's been of help

I must write something of an update actually. A couple of months ago my boot again appeared to be gathering condensation / water from somewhere. It's 3 years since I sealed these vents and presumed that the silicon had perished or come away from the car body, so off came the bumper for a look.

In actual fact the vents were still firmly in place and the water leak was coming via the sunroof drains being clogged at the front of the car. This allowed the water to back up and form as condensation under the headlining, and some had made it's way down to the boot, as well as the front and rear carpets. Luckily I caught it in time, but I had not de-clogged the drain lines for the sunroof since doing the vents. Hope this proves helpful to others

 Guess what i'm doing this weekend then

My driver's side, rear footwell is soaked, as others have complained of, too. My driver's side front footwell is now damp. The passenger side footwells, front and rear, are dry. The boot/trunk is completely dry. I heard I ought to snip the front rubber tubes that (apparently)come crimped from the factory. When I checked, the driver's side sunroof drain had been cut, but not the passenger side, so I cut it, too. My door seals look good, my headliner and seats are dry. Could it be the rear vent seals or the rear sunroof drains? Are the rear sunroof drains accessible w/o taking off the bumper?

Thanks

pic is from an A4, I believe, but looks quite similar to my MKIV Bora/Jetta.

 Great post, I managed to seal my rear vent seals using silicon from the inside by just removing the interior trim rather than the bumper. A dry boot and condensation free windows at last!!!!!

 Good job nihcad.....welcome to ukmkiv's

Hi guys, I found water inside beneath both of these vents. Just wanted to know nihcad if the vents are still water tight seling them from the inside?

 

The other thing is that it seems that both rear sunroof drain nipples are missing on my 99' gti and there are two 30mm rusty holes. Only checked it today as my near side rear door lock stopped working nd realised it must be water ingress, looks like rear washer tube has come off in the headliner.

Cheers for the post i wouldn't ave even known about this leak, gees mk4 don't half leak!!

 emz80, yes my boot is still nice & dry, give it a try

Subscribed....great write up Pat Think I'm gonna do this as general maintenance even though I don't have any leaks (touch wood)