Trunk/Kofferraum drain

[DieDane]

Hi All, hope someone can answer this question.

I realized that I had a lot a water in the trunk and that the foam supporting the hydralic pump was soaked. I removed the foam to dry everything. Under the hydralic pump and the foam, there is some sort of drainage hose (the gray one). Should that hose be connected to something?

[DavesZed]

That pipe normally has a 90 degree end on it that connects into the side of the battery as a drain away (if required). Looks like the battery has been changed to one that either didn't need it or they left the elbow on the old one and didn't realise.

[DieDane]

Thanks... Shouldn't there be some sort of drain hole somewhere? I mean any water in the trunk will end up in that battery/hydralic pump bay.

[Sergiu]

There doesn't seem to be any drain hole at all. I once had about 4 liters of windscreen washer fluid leak from a bag and the only solution was to pump it out.

[bigendbob]

Lack of drain hole is not the problem
Water getting in when it shouldn't is the problem.

[RobbiZ4]

Originally Posted by DavesZed

That pipe normally has a 90 degree end on it that connects into the side of the battery as a drain away (if required). Looks like the battery has been changed to one that either didn't need it or they left the elbow on the old one and didn't realise.

Correct. Even this replaced VARTA battery has a drain hole.

[Sergiu]

Originally Posted by bigendbob

Lack of drain hole is not the problem
Water getting in when it shouldn't is the problem.

Accidents happen, why not make sure the damage is minimal? It would have costed almost nothing to make a drain in the trunk.

[Mayhem]

You’ve discovered one of the frustrations of owning a Z4. The trunks often leak when it rains. If you aren’t careful, the water will accumulate in the recessed area and eventually ruin your roof’s hydraulic top. I learned this the hard way after having a roof failure and had to have my hydraulic motor repaired. I suggest you keep an eye on water incursion if your car is left in the rain.

[Sergiu]

Is drilling a hole somewhere in the recessed area that houses the battery and the hydraulic motor an option? Can it drain out without causing any harm? Just a question, looks like a very easy fix and I'm wondering if anyone has tried it.

[tranquility]

So I came from my thread
https://e89.zpost.com/forums/showthr...2#post27793042

and at first foolishly thought that the retained water in my trunk (I guess what everyone's talking about at the recessed area near the battery where the toolkit goes) was from the melted snow many mths ago but now it's summer haha, but it makes more sense there's a leak somewhere from whenever it rains, but it never occurred to me there could be water somehow leaking into the trunk but only getting the hidden/bottom part wet.

Anyway, where is the leak coming from exactly and are there any DIY solutions? I've been stuffing napkins into that area to try to soak up the water where the toolkit goes and there still seems to be a lot of residual water and it's not dry at all yet...how much freaking water is stuck there? Argh.

[bigendbob]

https://z4-forum.com/forum/viewtopic.php?t=77478

[tranquility]

Bump to see if there is an easy way to find the cause and solution?

[BugsBunny]

Tranquility, have you checked if the battery drain pipe is correctly connected on yours ? I will check mine tomorrow.

[tranquility]

Originally Posted by BugsBunny

Tranquility, have you checked if the battery drain pipe is correctly connected on yours ? I will check mine tomorrow.

I have no idea there is a drain pipe but will check. In any event, it is silly because like someone above said, water shouldn't be coming into that battery area in the first place. It's such a stupid design, doesn't even make sense and if the drain pipe exists, it's so stupid because I think they even put the battery up on stilts and ofc it has a foam surrounding, like they expect that area to get flooded...how about not having water coming into contact w the electricals in the first place like other well-designed cars?

Anyway, I think that the water is coming in from the rear wall, but can't locate it exactly. I'm trying to mitigate the prb stuffing cloths all over the place soaking up any water/trying to block any holes, etc.

[GerryC]

The 'drain' on the battery is a vent, not a drain. It is designed to vent any hydrogen gas from the battery overboard so that it doesn't accumulate in the trunk and cause an explosion.

The current AGM batteries come with vent holes on each end near the center top. That gray hose should have a 90 deg elbow that plugs into the vent hole. The hole on the other end should be plugged. It's usually a red plug that comes attached to the plastic positive terminal shipping cover. When the battery is installed the plug is snapped off the cover (which is discarded) and used to plug the vent hole that is not used.

Gerry

[bigendbob]

Use some food colouring or water based paint watered down.
Place some tissue around the battery box.
Then pour around closed boot gap.
Say pour red on left, green on the right.

My car is 2009 model, never been damp in the boot.

So they do seal.