Diagnosing sources of water ingress.

P

Pilchard

Member
I've had my car 9 months now and, not long after I got it, I began suspecting water ingress to the interior. Tell-tale signs like I began noticing light condensation in the top corners of the rear screen, a slightly damp feeling interior. Then one day I lifted the thin boot cover and there were beads of moisture on the battery, tool kit, and elsewhere. Since then it seems to have either got worse or maybe I'd driven through too many deep puddles... or something. I'd left an old bed sheet in the back from when I'd recently collected a bag of cement from my local builders' merchant, and a week later the sheet was wringing wet.
I have read that one of the more likely sources for leaks at the rear is the two vents that hide behind the bumper, but when I read about the convoluted process of bumper removal, I had to go to the toilet and then have a quiet half hour in a darkened room.

I washed it a day or two ago and gave the tailgate a good blasting with the hose... just in case. Nothing there.

So, my question is... before I gird my loins and begin destroying my car in the process of bumper removal only to find there is nothing wrong with the vents... is there a diagnostic pathway I can follow? It would seem to be a sensible precautionary alternative to just going gung-ho on the rear bumper.
 
Check rear lights are seated correctly and the tailgate rubber tubes for wiring are not damaged.

you can sometimes see the vents are not right by removing rear light access trims and shining a good light down but not always easy to get eyes on without the rear bumper removal.
 
You have OSS? If you do, make sure the rain channels are clean.

But if water collects around the battery, the vents are sure as hell the source.

- Bret
 
I had the same problem and everyone said it’s the rear seals behind the bumper!It was and it’s not a big job!! Yes the bumper has to come off! Put axle stands under rear take bumper off.then you have access! Follow instructions elsewhere on this site!! I prised vents out put a bead of sealant around them and refitted them.reassemble job done! I did purchase a set of trim removers off eBay £4 ish which made prising sides of bumper off easier!?
 
Wow! What a quick response! Love this forum.

PaulA2 said:
Check rear lights are seated correctly and the tailgate rubber tubes for wiring are not damaged.

you can sometimes see the vents are not right by removing rear light access trims and shining a good light down but not always easy to get eyes on without the rear bumper removal.
Click to expand...

As soon as it stops raining I'll do all you suggest.
 
bretti_kivi said:
You have OSS? If you do, make sure the rain channels are clean.

But if water collects around the battery, the vents are sure as hell the source.

- Bret
Click to expand...
Hi Bret... I'm not very good on these esoteric acronyms, so you'll have to tell me WTF OSS is.
 
Perhaps now IS a good time to check for water leaks. Fold down the rear seats, remove the roller blind and false floor and the access covers from the rear lights. Now with a good torch shine around all the seals and rear lights then the tailgate area to see if you can see rain coming in. Do the same for all 4 doors and also check front footwell to see if coming in past the heater.

BTW OSS is the Open Sky Sunroof.
 
robrace said:
I had the same problem and everyone said it’s the rear seals behind the bumper!It was and it’s not a big job!! Yes the bumper has to come off! Put axle stands under rear take bumper off.then you have access! Follow instructions elsewhere on this site!! I prised vents out put a bead of sealant around them and refitted them.reassemble job done! I did purchase a set of trim removers off eBay £4 ish which made prising sides of bumper off easier!?
Click to expand...
Yes, I remember reading your posts on this. It all gave me the horrors!. You and Bret are probably right though, so I'll bring up that thread again, buy a set of trim removers off Ebay... and some axle stands... and a pair of new vents, but not until I've just checked the easy stuff first.
Not looking forward to bumper removal though. My A2 is my only wheels at the mo... as my other motor is in doc getting brake pipes changed (MOT failure) and the garage needs TWO WEEKS!!! to do it cos they are blaming covid. So, the prospect of getting in deep, in the cold wet and dark (no home garage unfortunately) and finding myself snookered... isn't charming my socks off.
 
audifan said:
Perhaps now IS a good time to check for water leaks. Fold down the rear seats, remove the roller blind and false floor and the access covers from the rear lights. Now with a good torch shine around all the seals and rear lights then the tailgate area to see if you can see rain coming in. Do the same for all 4 doors and also check front footwell to see if coming in past the heater.

BTW OSS is the Open Sky Sunroof.
Click to expand...
All good advice. Will try it. I'll get the missus set up with the garden hose.... she'll love it.
So... OSS is a sunroof. LOL & TFFT... I don't have one.
 
Bumper off and back on again should be around 3-4 hours for a non-practiced person. Make sure you have some of the "Spreiznieten" - so the clips for the arch liners - spare (I would suggest at least 5 or so - they cost pennies so stock up!). Both wheels off, liners out, and then the bumper. You will need two people for the big bit.
I do not have trim removal tools and haven't needed them. Make sure you spend the time when you put it back on to line up the clips underneath the light clusters at the side of the car.

I would also try to do it when it's as warm as possible, as your plastics will get brittle. I already have snow lying - there's no way I'm going to try playing with the car until it's been in the garage (or a heated carpark) for a few hours. Do you have a shopping centre you could use for a while to get it as warm as possible before starting? I'd also practice the axle stand positioning at least once before you look at it in earnest. That way you don't faff for an hour, rushing - take your time, be sure you're happy with the positions, check out how much space you have and where things go, that the wheels aren't rusted on and you have the locking wheelnut key...

Where are you? Could someone maybe help with moral support? Teams conversation at the same time with video chat?

Also: if you have roofbars on, check those. Check the seals at the top of the doors. Make sure the windows haven't dropped a little. Check under the mats if any of the carpets are moist. Maybe even take the front seats out and then the carpet to check all the bungs are in place... that's another 2 hour job but only two and you get to clean stuff at the same time.

- Bret
 
bretti_kivi said:
Bumper off and back on again should be around 3-4 hours for a non-practiced person. Make sure you have some of the "Spreiznieten" - so the clips for the arch liners - spare (I would suggest at least 5 or so - they cost pennies so stock up!). Both wheels off, liners out, and then the bumper. You will need two people for the big bit.
I do not have trim removal tools and haven't needed them. Make sure you spend the time when you put it back on to line up the clips underneath the light clusters at the side of the car.

I would also try to do it when it's as warm as possible, as your plastics will get brittle. I already have snow lying - there's no way I'm going to try playing with the car until it's been in the garage (or a heated carpark) for a few hours. Do you have a shopping centre you could use for a while to get it as warm as possible before starting? I'd also practice the axle stand positioning at least once before you look at it in earnest. That way you don't faff for an hour, rushing - take your time, be sure you're happy with the positions, check out how much space you have and where things go, that the wheels aren't rusted on and you have the locking wheelnut key...

Where are you? Could someone maybe help with moral support? Teams conversation at the same time with video chat?

Also: if you have roofbars on, check those. Check the seals at the top of the doors. Make sure the windows haven't dropped a little. Check under the mats if any of the carpets are moist. Maybe even take the front seats out and then the carpet to check all the bungs are in place... that's another 2 hour job but only two and you get to clean stuff at the same time.

- Bret
Click to expand...
Sorry for the much delayed response... non-automotive life gets in the way.
Yesterday..... I carefully checked for any water ingress via door seals, window seals, and the rear light clusters with my wife enthusiastically aiming strong jets of water with the garden hose while I inspected from inside with a torch. Nothing.
I took PaulA2's advice and, with a powerful torch, looked at the rear of the light clusters while I had the black plastic covers off to see if I could see those suspect vents. I couldn't.
I even removed the black plastic panel that spans the back of the boot interior, which is held on by just three screws, just to see if that improves access or visibility. It don't.

So I'm now assuming it HAS to be the vents... so it's a bumper off job. I'll buy some axle-stands in the New Year and have a go at it. Here in West Cumbria we rarely get temps below zero degrees centigrade, even in January it is more likely to be 5 or 6 degrees, so the plastic trims should be safe in my careful hands doing the job outside in the cold.
I've not driven in much rain recently, so apart from a little condensation on metalwork beneath the battery/tool compartment cover, the car is relatively dry... ish. I'm guessing that the water coming in through those two leaking vents is just via road-spray beneath the car being forced up between the car body-shell and the bumper trim.
Am just hoping for minimal rain driving before I do the job.
Thanks for all the advice guys.
 
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