E85 Water Leak in engine bay/Wet driver side floor

[skmattwell]

Hi there, I lifted the driver side carpet the other day and found the floor was soaked underneath. Ive heard it's likely to be a cowl issue or the door seal. While trying to diagnose, I lifted the bonnet on a rainy night and saw this silver pipe looking thing (behind the engine) dripping down. The water sizzled each time as it dripped on something hot.

Could someone please advise me what this is a whether it's normal for it to be dripping? Could it be related to the driver side floor being wet?

Thanks!

[skmattwell]

[bigwinn]

That hole is your scuttle drain so should be dripping- it allows water to drain from your windscreen area out

I’d be looking at your door membranes matey

[enuff_zed]

That drain is just to let water out from around the wiper motor area, so not a problem.
The wet carpet will most likely be either be a damaged door membrane or the roof drain blocked so much that water is running over into the foot well.
Either way, I'd definitely be thinking of a way to cure it asap. In the meantime, unbolt the seat and tilt it over (so you don't have to unplug it) then check the yaw sensor under the carpet. As an interim measure, seal it in a poly bag with a sachet of silica gel in there too. If that gets wet it lights the dash up nicely.

[Zedebee]

That’s the drain from the cavity under the cowl on the driver’s side. You wouldn’t normally get water coming out of there unless the sides drains are blocked and overflowing into the cavity, or water is entering the cavity under the cowl (check gap between cowl and windscreen). Either way this could be the cause of water ingress to the cabin on the driver’s side.

[edit: I defer to bigwinn and enuff’s better judgement here, but I didn’t think a drip from here was “normal” unless something else was blocked?]

I’d take the cowl off, give everything a good clean out and make sure the drains are clear.

It’s worth noting that the sound deadening material under the seats holds a colossal amount of water, so you may have had the problem for some time without realising it; and it will take a good while to dry it out completely.

If clearing out the cowl/drains doesn’t solve the problem, next stop have a look at the door membranes; but also check the roof drains which can slosh water into the cabin if blocked (although you should be able to hear it sloshing around).

[enuff_zed]

[edit: I defer to bigwinn and enuff’s better judgement here, but I didn’t think a drip from here was “normal” unless something else was blocked?]

Got me thinking, so just been out with a hose.
Water does come out of there when it runs down off the windscreen.
Can't hurt to clean out under there though as well.

[enuff_zed]

Thought I'd get a couple of pics for you, with the scuttle panel removed.
You can clearly see that it is all one big area under there.
You can also see how much crud accumulates.
The hole in the third pic is where your rubber spout is fitted.

IMG_3426.jpg (62.28 KiB) Viewed 832 times

IMG_3424.jpg (76.5 KiB) Viewed 832 times

IMG_3425.jpg (76.02 KiB) Viewed 832 times

[skmattwell]

Excellent, thanks all. I have had the the scuttle panel off before and broke a couple of the brittle clips holding it down in the process. It no longer fits quite flush with the windscreen but didn't think it was an issue given there's no rubber seal between the window and the scuttle panel, so water could get in even if it were tight to the windscreen.

Will diagnose the roof drains and door membranes tomorrow. With a faulty door membrane I'm guessing a garden hose on the window should produce a drip at the bottom inside of the door?

[enuff_zed]

Excellent, thanks all. I have had the the scuttle panel off before and broke a couple of the brittle clips holding it down in the process. It no longer fits quite flush with the windscreen but didn't think it was an issue given there's no rubber seal between the window and the scuttle panel, so water could get in even if it were tight to the windscreen.

Will diagnose the roof drains and door membranes tomorrow. With a faulty door membrane I'm guessing a garden hose on the window should produce a drip at the bottom inside of the door?

Should work yes, but you'll need someone inside looking.
Save the yaw sensor though!

[skmattwell]

So after the hose on window test, I noticed a few small drops entering at the bottom of the door seal, which I'm presuming is the membrane failing to do its job? Didn't seem it would be enough to soak the entire floor, but maybe over time it would soak it nicely?

Am going to have a new cowl fitted as a precautionary measure too, as it is not at all tight to the windscreen.

Do you reckon I'll need to go to a BMW specialist for the membrane or is it a fairly simple job?

[enuff_zed]

It’s easy to fit with the correct sealant. Hopefully you can find a new one.
Ever the opportunist, I have a perfect cowl with every clip intact if you’re in need of one

[skmattwell]

Have just bought a new membrane from BMW, £38 happy days.

How much would you want for the cowl?

[enuff_zed]

Have just bought a new membrane from BMW, £38 happy days.

How much would you want for the cowl?

PM'd you

[skmattwell]

Predictably after replacing the cowl, the leak persisted. The weather has been so poor the last few days that I've resorted to doing the door membrane replacement in a sheltered asda car park

Here I go, wish me luck

[bigwinn]

Good luck matey