Coupe Rear Hatch/Window Seal Trapped Water?

[rollingstone]

I did a bit of searching but haven't found anything on this. But I assume if I'm having this (potential) problem, others may be as well...

I took my Coupe to the detailer today to debadge, swap amber for clear reflectors and get her back to a swirl and scratch-free showroom shine. But when we opened the rear hatch a reasonable amount of water poured out of the now inverted seals at the top of the window.

(See reference pics... orange arrows. Sorry, I'd have taken closer shots, but the car is in the shop and these were all I had on hand. The open trunk point to where the water came from... and it could be seen coming from between the seal and steel. The closed shot is just for more reference.)

Now, I had washed the car the day before AND we had quite a bit of rain later that same day (yes, after I washed the car)... BUT I am concerned that water was trapped somehow inside the hatch body, presumably between the seal and the sheet metal, AND I'm very concerned about the potential for rust developing from the inside!

I can't exactly go prop up the hatch for an hour or two after every rainstorm. The detailer said he figures the seal is somehow bad... on a 2007 car with 4,700 miles!

Has anyone noticed this problem... or IS it even a problem? It doesn't seem quite right. Any thoughts or insights are welcome and appreciated!

Cheers.

 

[Smokin]

Nice looking car!!!!!


I've always noticed water running into recessed area around the opening. Never looked to see just where it was coming from. My Probe GT did it too and my 325Ci did it when I opened the trunk. I'll have to look at exactly that area when I get home.

 

[rollingstone]

I've always noticed water running into recessed area around the opening. Never looked to see just where it was coming from. My Probe GT did it too and my 325Ci did it when I opened the trunk. I'll have to look at exactly that area when I get home.

On behalf of the car, thanks for the compliment... and on my behalf, thanks for looking. I'm going to talk with the service advisor at the dealer, too. Perhaps they know about this or, oddly, perhaps this is considered normal. If the rear deck lid was aluminum like the bonnet, I'd have less concern. It just seems like something they'd have caught when they were designing for water management.

If I find out anything from the service rep, I'll post it.

 

[Incompatible]

......If I find out anything from the service rep, I'll post it.

Please do.

 

[Smokin]

I'm not worried too much about corrosion the way BMW paints/seals those things. I do recall seeing two little holes at the top and at the base of the hatch. I have assumed they were for water drainage, but you know how assuming things goes.

 

[Breaker]

Excuse me if I'm being stupid here, and I'm sure you have checked this, but are you sure that water isn't the water that is held like a pool at the base of the rear screen when the hatch is closed and it rains? I get a lot of water running down the edge of the rear screen when I open the hatch after washing or it rains when this water runs off and it would look like water coming from where your picture shows.

 

[rollingstone]

Excuse me if I'm being stupid here, and I'm sure you have checked this, but are you sure that water isn't the water that is held like a pool at the base of the rear screen when the hatch is closed and it rains? I get a lot of water running down the edge of the rear screen when I open the hatch after washing or it rains when this water runs off and it would look like water coming from where your picture shows.

Indeed, because of this forum's sage advisors I was aware of the Z4's in-deck swimming pool. :lol: But I always take care to sop up any water... and following a rain-free day and the 10 mile highway drive to to detailer, the car was dry as could be. And we could actually observe water dripping from a tunnel-like gap between the seal and the metal.

I'll get the car back tomorrow and will post detail picks of the suspect areas. And I'm hopeful to learn more from the BMW service advisor.

I do appreciate everyone's input! Cheers to all.

 

[Smokin]

Rained last night so I checked it out--I think that water comes from the shape of the inside of the hatch-the part that actually fits against the weatherstripping. The window covers it, and unless you're really looking closely, you don't notice that it's wide enough to hold water in place until you lift the hatch and it runs off into the channel. Did your dealer have an explanation ?

 

[Top pup]

The water you've seen will have sat at the base of the rear screen under the rubber, the rubber strip around the rear window isn't a seal it is mearly a trim and isn't susposed to be water tight. The rubbers around most screens are just trims these days.

 

[rollingstone]

The water you've seen will have sat at the base of the rear screen under the rubber, the rubber strip around the rear window isn't a seal it is mearly a trim and isn't susposed to be water tight. The rubbers around most screens are just trims these days.

Hmm... I see what you're saying, but cant understand why such a thing isn't water tight. I guess it's just to add a finished look, but the idea of trapped water of any kind is a bit worrisome (even given BMW's reputation for excellent paint-sealant process and rust warranty). It can't hurt to ask, I suppose.

Rained last night so I checked it out--I think that water comes from the shape of the inside of the hatch-the part that actually fits against the weatherstripping. The window covers it, and unless you're really looking closely, you don't notice that it's wide enough to hold water in place until you lift the hatch and it runs off into the channel. Did your dealer have an explanation ?

I haven't spoken to the dealer just yet. I get the car back from detail tomorrow and then will be at the dealer Saturday. I hope to speak to them then, just even to put any concerns to rest.

 

[Top pup]

The water you've seen will have sat at the base of the rear screen under the rubber, the rubber strip around the rear window isn't a seal it is mearly a trim and isn't susposed to be water tight. The rubbers around most screens are just trims these days.

Hmm... I see what you're saying, but cant understand why such a thing isn't water tight. I guess it's just to add a finished look, but the idea of trapped water of any kind is a bit worrisome (even given BMW's reputation for excellent paint-sealant process and rust warranty). It can't hurt to ask, I suppose.

Yes is simply there to tidy up the edge of the window nothing else. I do have to admit that the idea of leaving the water sitting there is a bit poor really.

 

[rollingstone]

Yes is simply there to tidy up the edge of the window nothing else. I do have to admit that the idea of leaving the water sitting there is a bit poor really.

Thanks for the insight. Though not necessarily mind-easing, I'll not fret over it too much then. Certainly none of it is finding its way into the trunk... yet (gulp). When I'm at the dealer this weekend, I'll still ask, but suspect I'll get the answer you just gave.

Cheers.

 

[scottyD]

I definitely noticed this after taking a trip this afternoon in the rain - there were several drips in the areas you mentioned once opening the tailgate...

I also noticed this happening after washing the car....After drying all the water out of the pool area where the window meets the spoiler, I'll come back to it a couple minutes later and see that it's filling up with water again, after I've already dried everything....this happens several times after washing the car, so apparently water can flow downward as well...

No leakage into the trunk (yet) for me either, but let us all know what you find out from the dealer, if anything...

 

[rollingstone]

...but let us all know what you find out from the dealer, if anything...

Okay, so long story short (on the rear hatch/window seal question)... completely normal.

The dealership I purchased the car from hosted a "New Owner's Clinic" to talk about warranty and maintenance issues, and give a tour of their service area. It was quite interesting, actually... we have a great dealership, staffed with great people delivering top-notch service.

I was able to meet and talk to the head shop technician, who look at the seals and then wen on to explain the construction of the rear deck and why this (seeming snafu) in water management was perfectly normal. Better still, he was quick to notice the few mostly "visual" enhancements to the car and spent a lot of time extolling the virtues of the Z4.

So no worries and leaks and rust should never be an issue... AND IF something does ever happen, that's what the warranty is for.

Cheers to all for your input!

 

[Breaker]

Thanks for that.
Since you posted this thread I tested mine when the car had dried out after a rain shower and mine did the same. Was going to say I think it's normal.