Water leak in trunk

[Alibs555]

Good morning,

My daughter's 1986 325 2door has a water leak. It's in the trunk, on the left side where the jack is. There is also water in the right rear footwell in the cab. Where are the waterleaks notoriously coming from in the e30? Any help or thoughts would be appreciated.

Thank you,

-alibs555
On the beautiful north shore of Vancouver BC

[ravstar13]

I had this is the exact same place and it was a hole i couldnt see from the inner arch(I had some carpet over it so It was coming through the carpet, so I couldnt see it), which I got welded and now have no water in there since. Mind you it was like swiss cheese.....Some have had it because of the boot seal pershing. There could be other reason which i am sure people will guide you with. But them two places are the best bet.

[jcm325]

If it has a sunroof start with that they can be the cause of many water leaks, either blocked drains or rust on the cassette....

[Brianmoooore]

A few other places are coming past the boot seal simply because the hinges/catch aren't adjusted properly, holes in the channel under the boot seal and hidden by it (there's a welded join each side which is notorious), seals on the rear lights, missing gaskets on the vent. extractors behind the sides of the rear bumper, and a missing drain tube on a boot mounted antenna.
There are actually drain holes in the wells each side, formed by a 'v' shaped notch in one panel where it is welded to the panel behind it. These are only to drain the first coat paint from the shell at the factory, and are sealed with seam sealant in the finished car.

[Alibs555]

Thank you Gents, very much appreciated. I guess I know what I'm doing this weekend... Hopefully I won't run into nightmares...

Can the trunk (boot) seal be leaking itself? I imagine it is still the original on there....should I just replace that, or can it be "revived"?

How does one clear the sunroof drains?

Thank you for any input.

[Brianmoooore]

Different climate can affect things differently to the UK climate, but I've never seen any rubber in need of being 'revived' yet, on any E30. Changed the odd door seal which has been damaged or worn away, but that's all.
Check the seal by trapping a sheet of paper in the closed boot, at various points around it, and see how easily the paper can be pulled free. Even if you find somewhere where there is no resistance, it can be dealt with by adjustment.
Clear sunroof drains by threading a piece of electrical wire through them, although it's easy enough to check them individually by parking the corner of the car opposite the drain you are testing on a block, pouring water into the drainage channel around the open roof, and making sure it promptly appears on the ground under the drain points, and nowhere else.

[Alibs555]

Thanks Brian,

I had heard you can use a rubber reconditioner (lithium grease ??) to make the seal swell again to improve it. Is there any merit to that?

[Brianmoooore]

Hydrocarbons of any kind will make rubber swell, but that's as it breaks the rubber down and rots it, so I don't think I'd recommend it.

[Alibs555]

That makes sense. Some say Silicone grease is alright.

So I checked the sunroof drains ...all clear.
Stripped down the boot... Dried all the inside. I am unsure as to where the water is coming in from, but in the well where the jack is stowed, there seems to be a bit of rust starting. For now I've left all the panels off and will monitor as I drive the car.

As to the right rear footwell, I have not managed to get it all dry as I would need to remove the right seat and start removing centre console and carpeting. Are the floor boards very susceptible to rusting/perforation? I've checked the door and window seals and they seem to fit well and be dry.

Again thank you for any help.

[Brianmoooore]

Any tiny, just visible, sign og bubbling in the paint, with an orange tinge, will turn out to be a considerable sized hole when investigated!
Damp rear foot well is usually the failure of a steel drain plug, situated almost centrally under the front seat. This plug has three locking tabs that twist into the body, and the chances are that one or more of these tabs has rotted off, the sealant has cracked, and water is getting in.
Check from underneath the car.
Silicon grease is safe with rubbber, but only as a lubricant. It has no effect on the rubber at all.
Talcum powder sprinkled around the boot will show where water is running down.

[ChrisHC]

I found some water in the boot of my Sport over the weekend and I wondered whether it might have come in through fixing holes for the boot lid spoiler, does that seem possible?

[TriggerFish]

I've had good success with sprinkling the area around a leak with talcum powder and tracing the lines the water leaves in find the ingress point.

[scallyally]

I found some water in the boot of my Sport over the weekend and I wondered whether it might have come in through fixing holes for the boot lid spoiler, does that seem possible?

Certainly possible if the spoiler was fitted without the sponge sealing washers on the studs underneath the spoiler.