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Pontiac Bonneville Water Leaks

I have a 2000 Bonneville SSE-I and we just got a huge amount of rain here in Cincinnati and my rear driver floor board is accumulating water and no where else.

I can not find wet spots on the roof or door area. Get this I vacuumed it up this morning at a Car Wash paid a couple bills maybe 15 minutes later AFTER cleaning it real good BAM again an inch if water same area and no water marks anywhere.

I know under the driver and passenger seats there are vents maybe from there please give me some light on this.

Thank you,



  • imidazol97imidazol97 Crossroads of America: I70 & I75Posts: 18,054
    Those leaks seem to be related to

    1) door seal inside door which is a plastic sheet held by a butyl-like sticky caulk that sometimes loosens or is not replaced during a repair and lets water in
    2) sunroom drain lines not draining properly and water gets into floor area
    3) a trunk leak

    I have sent some more information about leaks to your carspace email account here on Edmunds. Click on the grey bar word "Mailbox" in the top of this page and read the email from there.
  • I am dumbfounded by this issue because I do not see water stains anywhere and get this all the seals are beautiful because before I got it was a garaged car so the seals and whole car look brand new.

    I did not get an email from you I opened the email box and the pop screen came up I pressed check email and nada.

    Thank you,

  • imidazol97imidazol97 Crossroads of America: I70 & I75Posts: 18,054
    I just checked my carspace email page and it says it was sent at 5:39 am (Pacific time). I jsut resent a copy and a carbon came back to me at my account.
  • Hi, I have the same issue with my 1999 Bonneville. Were you able to find the cause? Thanks.

    C. J.
  • Recently purchased 2003 Bonneville SLE. Discovered rear floor on driver's side was wet. Dried it out completely. Took it through the car wash a couple of times, had a little rain, never saw evidence of leaking anywhere. Rear floor again extremely wet!! Front slightly wet. Removed drivers seat, took all carpet out, the floor slopes to the back. No obvious holes or cracks in floor. Can't figure it out. Has happened three times in the last month.

    Would appreciate any suggestions.
  • Just you have a sunroof?
  • imidazol97imidazol97 Crossroads of America: I70 & I75Posts: 18,054
    You're right about sunroof. Sunroof drains can block up. They come out behind the front wheels IIRC from another site where this is discussed a lot.

    Also, the water shield inside the front doors can be loose especially if the door has ever been serviced for window problems. The plastic is glued to the metal frame with a butyl caulk. This lets water through that drains into the door around the windows and then it gets onto the floor. Also check the rubber seals around the perimeter of the door.

    Do you have water in the bottom of the trunk in the spare well?
  • imidazol97imidazol97 Crossroads of America: I70 & I75Posts: 18,054
    If you have a sun room pour water into the trough and watch for it to come out under the car or back up as you pour it in rather than go through one of the 4 drains.

    If you have possible door leaks, spray them with a garden hose and then inspect for water running down the plain metal at the bottom of the doors.

    I have picture help for both of these. I can send articles to your carspace email address here on edmunds if you activate those. Or you can send an email to my address in my profile. Click on the use name that shows who posted to see their info and profile; one of my emails is there.

    Or send to my carspace email which is my user name plus the "at" sign and
  • Found the problem-after removing carpeting and wiping up the floor, I ran the hose on the sunroof and water came in the car right behind the emergency break pedal. Becauase of the slope of the floor to the back it runs down the channels in the floor pan and pools on the back seet floor. The sunroof drain tube comes down the left side of the windshield behind the plastic molding, through a hole in behind the dash. It's supposed to drain outside of the car but wasn't.

    So far no water in the spare well.

    Thanks for the info!
  • imidazol97imidazol97 Crossroads of America: I70 & I75Posts: 18,054
    Sunroof leaks. Go to my profile by clicking on my user name at top of this message and read my profile. Copy the link to a picture rich help guide for sunroof drain tube repairs.
  • raeluraelu Posts: 1
    I have a 1994 Bonne and for the past several months has had water accumulating in my trunk. It's gotten so bad lately that I have puddles on my floor in back though not as yet in the front. What can I do? I think it might be my seals. I'm new to car ownership and at a loss as to the best way to go about fixing this problem.

    Thanks for any help.
  • tgsmyerstgsmyers Posts: 3
    Please send me the picture and anything else concerning the drain for the sun roof. I had a mechanic rework the door seals but I still gets lots of water. I am now sure my sun roof drain is the problem.

  • imidazol97imidazol97 Crossroads of America: I70 & I75Posts: 18,054
    You need to set up your carspace page so I can send emails to your car space address with the pictures. Click on "My Carspace" in the green bar at the top of the page (green for St. Patrick's Day?).
  • tgsmyerstgsmyers Posts: 3
    My page is set up. Please send the pictures.


  • elsiaelsia Posts: 1
    I also have water pooling under my drivers seat in my 2000 bonneville. When putting a garden hose on your sun roof you are suppose to have it shut right? This probably sounds silly but i don't know how to figure this problem out and it has caused electrical problems with the wires under my seat. Three windows and three door locks stopped working. Dealership said the electrical harness had water corrosion on it and charged me $400.00. Windows and doors work now but there is still water coming in. HELP
  • imidazol97imidazol97 Crossroads of America: I70 & I75Posts: 18,054
    While it's most likely to be a disconnected sunroom drain next to your parking brake area...,

    don't forget to run water around the window on the driver's door so it can leak around the slide seal where it goes up and down and get in on the passenger side and look for water on the metal around the inside of the door toward the driver.

    Water that gets inside the door is kept out of passenger area by a plastic shield which is caulked to the perimeter of the door. But that caulk ages or is not replaced correctly if someone took off the inner panel to do work, such as window motors.

    And the water can drip into the interior. It comes in under the door trim but outside the metal.

    Check your carspace mailbox for some more info on these leak problems.
  • tgsmyerstgsmyers Posts: 3
    I have set up my page. Would you please email me the pictures of the Bonneville water leak repair. I am getting desperate. I have been to the garage twice and still no fix.

  • apaxsonapaxson Posts: 1
    I am new on this web-site and it looks like you might have all the answers I am looking for. I have a 2000 Bonneville with no sunroof that leaks water into the interior with every rainfall. It pools on the floor in front of and behind the drivers seat. I've noticed that you have sent pictures and etc. to other owner regarding this situation..........can you please help me out.

  • imidazol97imidazol97 Crossroads of America: I70 & I75Posts: 18,054
    I did what you asked.

    The butyl caulk that seals the plastic liner to the metal of the door ages and lets the water drip on down the door and it drips inside the car. The butyl makes the water go back into the door where it drips out drains on the bottom of the door that are outside the rubber sealing strips so the water ends up outside the car.

    There are some other leak problems around taillights into the trunk and the spare tire storage well and around the spoiler wings.
  • Seems that I just purchased a used '02 bonneville and was unaware of the water issue. Have the same issue with water in the back 2 floor boards. Also have the problem w/3 of the window-door looks not working. Any help would be great.
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