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Discussion Starter #1
Hi,

Well last night I experienced water leaking from one of my rear vanity lights. It looks like this is related to the sunroof and a common problem.

I have a 2000 s500. Are there two (front only), or four sunroof drains? Also, I could not see any of the sunroof drains when I looked - are they hard to find? a picture or two would be great.

However, it sounds like people say the seal itself is more often the issue - how do you confirm if this is the case? I can't believe on a car like this these sorts of problems are happening, I mean blocked sunroof drains is fair enough, but seriously, the integrity of the rubber seal being compromised after 11 years? The car was parked on a slight uphill gradient (rear of car was lower) at the time, if the makes a difference.
I've attached some photos of how my sunroof looks. It looks fine to me.

Also, I read some of the horror stories of foot wells becoming water-logged due to blocked drains (and the resulting fried SAM's). Can someone tell me which drains need to be checked and cleaned to prevent this? The only one I could find is located at the bottom of the black plastic mesh assembly under the hood, it's draining fine though. I've attached a photo of grill which has the drain I'm talking about.

Thanks guys
 

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Hi,

Well last night I experienced water leaking from one of my rear vanity lights. It looks like this is related to the sunroof and a common problem.

I have a 2000 s500. Are there two (front only), or four sunroof drains? Also, I could not see any of the sunroof drains when I looked - are they hard to find? a picture or two would be great.

However, it sounds like people say the seal itself is more often the issue - how do you confirm if this is the case? I can't believe on a car like this these sorts of problems are happening, I mean blocked sunroof drains is fair enough, but seriously, the integrity of the rubber seal being compromised after 11 years? The car was parked on a slight uphill gradient (rear of car was lower) at the time, if the makes a difference.
I've attached some photos of how my sunroof looks. It looks fine to me.

Also, I read some of the horror stories of foot wells becoming water-logged due to blocked drains (and the resulting fried SAM's). Can someone tell me which drains need to be checked and cleaned to prevent this? The only one I could find is located at the bottom of the black plastic mesh assembly under the hood, it's draining fine though. I've attached a photo of grill which has the drain I'm talking about.

Thanks guys
Your forth picture clearly shows the grate under which debris can build up and cause a leak. That grate has 3 or 4 tabs around it that can be released for removal. Then you can easily clean this area out. The sunroof has two drain holes in the front. One of your pictures almost shows them but the lighting is poor. Get a light and look in the forward most corner and you'll see the holes. These will drain into the outer body of the car that is covered by the rocker panels. There are two drains on each side that can be cleaned out after removing the rocker panels. I went through all of this and the drains were fine. I believe there are also two drains at the back of the sunroof chanels but they're a little harder to see and access. Hope this helps a little. I think the key is that any time you see debris on these cars remove it and try try try to keep them garaged as much as possible.
 

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Discussion Starter #3
Thanks for the reply. The rocker panels that you are talking about, would you be able to describe exactly where they are? and where the rear drains exit, if you know that?
 

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Thanks for the reply. The rocker panels that you are talking about, would you be able to describe exactly where they are? and where the rear drains exit, if you know that?
It may be called a rocker panel cover. It's the exterior curved panel beneath the doors that runs the length between front and rear wheels. It is removed by taking out about 6-8 fasteners underneath and a bolt in the front and rear wheel well.
Once you have this panel off it will expose two plugs (Front and rear) with a small drain hole in the center. These drain holes can clog easily. With the panels off you can pour water down the sunroof drains and see exactly where they drain. This is a simple procedure but it takes a little time and as I said mine were not clogged.
 

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same water leak out of passenger root vanity light

Bizarre leak. Driving thru intense downpour and water began dripping out of the vanity light quite a bit.

What could allow this to happen & what is the best way to repair?
 

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If the drains are clear of blockage, then the sunroof frame is most likely rusted and leaking. This happened to my s500 a couple of years ago. Very costly to repair/replace. Dealer would be over $2000. Indy is best bet. You will need to source the part (frame) and use someone familiar with sunroof repair. (I thought I saw rust in one of the photos up top.)

The outter seal is not designed to keep all water out. I suspect that when a sunroof is rarely opened, moisture is trapped for long periods, hence rust develops on the poorly treated frame. I recommend opening roofs to dry after being exposed to rain/water.
 

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Discussion Starter #10
A long time has passed since I posted this, but I still haven't got to the bottom of the issue, although it hasn't happened again since. Is it possible that everything was working as normal but due to the amount of rain and the fact that the car was parked on an angle (with the back of the car lower than the front), that the rear sunroof drains just couldn't cope with the amount of water and it went into the roof lining instead?

2strokepwer, were you referring to the very first photo were there is rust colour in the upper left corner of the photo? Is this a telltale sign of a rusted frame? :/

Finally, I have found the front sunroof drains but not the rear ones. A small amount of water is lying near each of the front drains; looking at the design of the inlet to the drain there is a slight lip which seems to prevent small amounts of water like this from getting in.
Can anyone help me out with find the rear drains - how far back are they; are they accessible? If anyone has or can take photos pointing them out if would be greatly appreciated...thanks!
 

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Discussion Starter #11
Anyone?
Surely someone has the exact location of the rear sunroof drains on a W220.
I also can't find the location where they drain out of the car (which I believe is somewhere in front of the rear wheels) - again, if anyone has or can take some photos to show this, it would be most appreciated!
 

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Discussion Starter #13
Yeah, I am hoping I don't have a rusted frame (obviously) - I've had a good look at the inside of the sunroof with it open and I can't really see any evidence of rust..
I did try a test of pouring water onto both rear corners of the sunroof (with it closed) and the only water that drained out was via the front sunroof drains, so I'd really like to check the rear drains at both ends..
 
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