2008 Cadillac CTS Sunroof Drainage Problem
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  • 1 Post By Leo_p
2008-2013 Cadillac CTS General Discussion Discussion, 2008 Cadillac CTS Sunroof Drainage Problem in Cadillac CTS Second Generation Forum - 2008-2013; So I've got this problem where the drainage system from the sunroof/moonroof gets periodically clogged and causes rain water to ...
  1. #1
    mivey4 is offline Cadillac Owners Member
    Automobile(s): Cadillac CTS 2008
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    Smile 2008 Cadillac CTS Sunroof Drainage Problem

    So I've got this problem where the drainage system from the sunroof/moonroof gets periodically clogged and causes rain water to drain into the inside of my Vehicle. Usually the water will drain from under my glove compartment onto the passenger side floor. I have had this problem in the past and it gave me a scare before the actual cause was explained.

    For anyone reading this post and may not have experienced this yet, there is a drainage system in the sunroof that redirects any water that gets through the seals back to the outside of the vehicle. Periodically the system can become clogged causing the water to get back flowed into the car.

    Personally, I would have expected that the seals would not allow that in the first place.

    Anyway, there is a large tree in my yard and during the spring both my vehicles get covered in yellow pollen. Apparently, the pollen is small enough to get past the seals and clog the drainage lines every year causing this problem.

    Last year I took the car to the Cadillac Dealership and they cleaned the drainage hoses. (Problem Solved) But this is quickly becoming an costly expense to do this every year.

    I have read in other places that some folks have successfully managed to perform this task themselves but there are no details as to how this is done.

    Has anyone in this forum had the problem and resolved it without taking it in and paying for the service??? If so, I'd certainly be very grateful if you wouldn't mind sharing the information so I make try to take a crack at it. I just need to know how to begin.

    Any other advice or suggestions for this would also be appreciated.

    Thanks!

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  3. #2
    tinman's Avatar
    tinman is online now Cadillac Owners Connoisseur
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    Re: 2008 Cadillac CTS Sunroof Drainage Problem

    Man, this topic has been covered so many time. Soooooo Many.

    Search is your friend.

  4. #3
    mivey4 is offline Cadillac Owners Member
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    Re: 2008 Cadillac CTS Sunroof Drainage Problem

    Thanks tinman. I'll search again, maybe I didn't perform enough variations on the keywords.

  5. #4
    tinman's Avatar
    tinman is online now Cadillac Owners Connoisseur
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    Re: 2008 Cadillac CTS Sunroof Drainage Problem

    27. Ultraview Sunroof Water Leak in Passenger Floor Area

    Try using a turkey baster as a “toilet plunger” and work the drain with water in it. Try the ol’ “in and out” routine until it hopefully forces the water and debris out the drain line. Then the light bulb went off. With the drain lines full of water along with the sunroof tray, I put the turkey baster directly on the drain hole and started pumping. I started feeling some resistance and then the clog finally gave way. A perfect stream of water was now flowing onto the driveway at the bottom of wheel well.
    OR
    Use thick monofilament or weed wacker line to run through the 4 drains. Smooth out the cut end of the line with sandpaper to help it slide through the drains.

    Open sunroof.

    Front: Take a cup of water and carefully pour into front drain channel to gauge initial drain rate. Use weed wacker line and rod out front drains from roof. The front drain lines run down the "A" pillars and exit out the side (behind the fender) about a foot below the top of the dash, about 3-1/2 feet. Pour more water and observe draining. Run weed wacker line again. Repeat until satisfied. You should notice the run off puddling behind the front wheels and may also observe dirt/sludge/algae that was in the lines.

    Rear: The rear drain lines run down the "C" pillars into the trunk and exit out the rear wheelhouses. Peel back the sides of the trunk liner to access the drain lines. The right rear drain line can be seen by removing the battery access cover, but it is difficult to work with unless you peel back the liner. Detach the rear lines from the wheel well grommets and run weed wacker line up the drain lines. The distance from the drain outlet to the sunroof is about 4-1/2 feet. Place the drain line in a bucket or bottle. Carefully pour water into the side drain channels of the sunroof. You may want to have someone pour water in the channels while you observe the flow into the bucket/bottle. Run weed wacker line again. Repeat until satisfied.

    All sunroofs leak some water and that leak off is normally handled by the drain lines. IMO this sunroof is a flawed design for two reasons. (1) The fixed portion of the sunroof uses the same type of perimeter seal the moving portion uses and therefore doubles the amount of leak off compared to a standard sunroof; (2) The drain lines are undersized even for a standard sized sunroof. As a result of this, the drain lines, at best, are barely adequate for a light rain. Throw in a little bit of clogging and a more intense rain and we get what we all complain about. After constantly cleaning lines and still living with leaks, I removed my headliner to see if I could resolve this problem. I replaced all four lines with 1/2" I.D. tubing in place of the factory 1/4" I.D. and have had zero leakage even in a total downpour (I live in Florida).

    Use 1/2" I.D - 5/8" O.D. clear hose from any hardware store. I considered 3/8", but why not not use the largest size that will fit?

    The 4 drain nipples on the corner of the sunroof are 1/2” O.D. There is a grommet on each corner that reduces them to 3/8” O.D. to fit the original drain lines. The clear hose fit perfectly on the sunroof nipples once the reducer was removed. There are clips on the stock hose that keep them in place (2 in the rear and 3 in front - 2 on "A" pillar, 1 under dash). Remove the clips from the stock hose, tape precut lengths of new hose to them (roof side) and then pull the whole thing through the trunk and underdash, respectively. Place a grommet around the front lines and secure the grommet to the existing inner fender holes. The fronts were a pain to get to and you have to slightly enlarge the hole to accomadate the larger grommet. The rears were easy. Secure the new hose to a 1/2” nipple and push it through the existing wheelhouse grommet.

    Removing and reinstalling the interior parts (especially the headliner) takes patience and took the longest time, but is not overly difficult. I removed the headliner from my car, but I would recommend leaving it in and trying to work around it. There are two electrical harnesses that are glued to the headliner that I had to remove and then reattach when installing.

    Originally Posted by loosend
    What so you mean about the 1 under the dash and how does that one come into play? Is it the AC condenser drain tube or related to the sunroof? How do you get to that one under the dash?

    The nylon clips clamp around the hose and then push into a body hole with a barbed end. In order to pull the stock hoses out you have to remove these clips. The front hoses have two clips on the "A" pillar that are easily removed. There is a third hose clip that can only be removed by reaching under the dash. The sunroof drains only drain the sunroof.

    *Remove the front kick panels (these are the plastic side panels under the dash - to the left of the driver's feet, right of the passenger's feet.
    *Remove under dash trim plates - plastic panels under driver and passenger dash area - both have lights that need to be unplugged. Passenger side has airbag control module (I think it was) that needs to be unplugged also.
    *Once these panels are removed, reach up and peel back the carpeting from the outer corners. The carpeting has attached insulation and is fairly rigid so takes a little effort to move. On the driver’s side there is also a styrofoam wedge (dead pedal) that I found easier to remove and then glue back to the carpeting.
    *With a light, look up under the dash to the now exposed side area (I ended up on my back for this part). You should see the drain hose coming down (if you follow the hose up you should now see the third clip) and then going through an access hole and finally plugging into a grommet in the inner fender. Tugging a little on the drain hose from above (while you're lying under the dash) may help to identify what you are looking at.

  6. #5
    mivey4 is offline Cadillac Owners Member
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    Re: 2008 Cadillac CTS Sunroof Drainage Problem

    Ok, got it. Ironically enough, I found the post you'd previously put up about this around the same time you posted your second response here:
    http://www.cadillacforums.com/forums...ged-drain.html

    I'll give the Turkey plunger approach a shot since the other options seem a bit more involved than I'd imagined. Especially involving the removal of the headliner (cringe!)

    Once I unclog them I believe I'll just take precautionary measures and cover the sunroof seals with Duct Tape during times of high pollen to alleviate the debris from clogging the drains.

    Seems like Cadillac dropped the ball on this one IMHO but what can you do?

    Great vehicle overall though.

    Thanks tinman

  7. #6
    tinman's Avatar
    tinman is online now Cadillac Owners Connoisseur
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    Re: 2008 Cadillac CTS Sunroof Drainage Problem

    You're welcome. Options to tape, which will leave a residue, include a quick hose rinse daily or using painters tape. Not sure if the painters tape will hold up at 80 mph, but it certainly won't leave a residue. Doesn't look too good or classy, but it is an option.

  8. #7
    Kevin2050 is offline Cadillac Owners Member
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    You can always seal the rear panel of glass using black silicon window cauk...it blends in well and if you take your time when applying it looks great.

  9. #8
    Leo_p is offline Cadillac Owners Member
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    Re: 2008 Cadillac CTS Sunroof Drainage Problem

    Consider a car cover?
    tinman likes this.

  10. #9
    tinman's Avatar
    tinman is online now Cadillac Owners Connoisseur
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    Re: 2008 Cadillac CTS Sunroof Drainage Problem

    Quote Originally Posted by Leo_p View Post
    Consider a car cover?
    Well, like, yeah. That's a good idea, Leo. Doh!

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