I have read many of the posts about water in the car. I thought that I would add mine. At first I thought that it was the kids leaving their water bottles on the floor because the back right passenger floor was wet. After I dried it out, it happened again so I knew something was up. Well now after a pouring rain, the whole passenger side carpet front & back is soaking wet. The trunk is bone dry! I saw something about calk wearing off a seam in the floor? I live in the south so the car does not see snow or ice. Maybe it's a defect from the get go. Has anybody else had water coming in from the floor boards? Where do I find the moon roof drain lines? I did not realize that there were any.
Thanks!
Water in Car
- mblaze
- SLE Member

- Posts: 34
- Joined: Wed Dec 10, 2008 8:43 pm
- Year and Trim: 2005 Bonneville GXP
- Location: South Carolina
Water in Car
Blaze
-
ddalder
- Resident Gearhead

- Posts: 2599
- Joined: Wed Apr 01, 2009 7:11 pm
- Year and Trim: 2004 GXP, 2008 STS, 2020 XT6
- Location: Alberta, Canada
Re: Water in Car
There were some issues with moonroof drains along with some areas that are intended to be "wet" cavities in the car that were filled with too much insulation and caused problems. Being that yours is a 2005, these problems (according to TSB's) should have been resolved at the manufacturing level.
What hasn't been addressed is the door panel water deflectors. Next time you have a heavy rain or take your car to the wash, look very closely at the bottom of your interior door panels for water. There is a plastic sheet that is attached to the sheet metal underneath the door panel that is supposed to keep water out. The adhesive GM uses is poor, at best! It is never very long before the deflector pulls away and water starts leaking into the car. It is VERY common to have it accumulate under the carpet in the rear seats. I'm starting to lose count of the number of 2K+ Bonnevilles I fixed this problem on.
If there isn't one already on this board, I have a write-up I'll be posting on how to check for and fix this problem. I don't believe that caulking rubbing away is the most common reason for this problem. Most members will tell you it has been one of the following:
Moonroof drains plugged or disconnected.
Poor adhesion of door panel water deflectors.
Damaged or otherwise poor weatherstripping.
What hasn't been addressed is the door panel water deflectors. Next time you have a heavy rain or take your car to the wash, look very closely at the bottom of your interior door panels for water. There is a plastic sheet that is attached to the sheet metal underneath the door panel that is supposed to keep water out. The adhesive GM uses is poor, at best! It is never very long before the deflector pulls away and water starts leaking into the car. It is VERY common to have it accumulate under the carpet in the rear seats. I'm starting to lose count of the number of 2K+ Bonnevilles I fixed this problem on.
If there isn't one already on this board, I have a write-up I'll be posting on how to check for and fix this problem. I don't believe that caulking rubbing away is the most common reason for this problem. Most members will tell you it has been one of the following:
Moonroof drains plugged or disconnected.
Poor adhesion of door panel water deflectors.
Damaged or otherwise poor weatherstripping.
Last edited by ddalder on Mon Apr 06, 2009 10:36 pm, edited 1 time in total.

Bose Luxury Sound System w/Touch Screen Navigation, Addition of Factory XM, 2005 MY Antenna, OnStar Upgrade (3G),
RainSense Wipers, Backup Camera, '00 Style Door Panel Courtesy Lights, Heated Washer Solvent, 2X Remote Trunk Release,
Turn Signal Mirrors, Center Console Courtesy Lamp, Rear Outboard Heated Seats, PVD Chrome 18" Factory Rims, Upgraded
Carbon Fibre Appearance Interior Trim, Highly Modified Main Body Harness, Instrument Panel, Door, Door Panel & Headliner
Wiring Harnesses, Custom Fuse Box & Tire and Loading Information Decals, Additional Acoustic Insulation[/size][/color]
- mblaze
- SLE Member

- Posts: 34
- Joined: Wed Dec 10, 2008 8:43 pm
- Year and Trim: 2005 Bonneville GXP
- Location: South Carolina
Re: Water in Car
Thanks ddalder, I will check that out. I have spent a couple of thousand this year at the dealer and I'm tapped out.
I am going to have to try to fix it myself. Thanks for the advice.
Blaze
-
ddalder
- Resident Gearhead

- Posts: 2599
- Joined: Wed Apr 01, 2009 7:11 pm
- Year and Trim: 2004 GXP, 2008 STS, 2020 XT6
- Location: Alberta, Canada
Re: Water in Car
This repair should be pretty easy to complete yourself. If someone knows of a write-up already on the forum, perhaps they can post the link. Otherwise I had one previously that I've already started updating. It may be 4 or 5 more days though before it's ready to go up.
This biggest part of this repair is just the labour. You need some Bug & Tar remover, rags, new sealant and just some time to spend doing it. Pretty cheap overall. The write-up will pretty much walk you through the process
This biggest part of this repair is just the labour. You need some Bug & Tar remover, rags, new sealant and just some time to spend doing it. Pretty cheap overall. The write-up will pretty much walk you through the process

Bose Luxury Sound System w/Touch Screen Navigation, Addition of Factory XM, 2005 MY Antenna, OnStar Upgrade (3G),
RainSense Wipers, Backup Camera, '00 Style Door Panel Courtesy Lights, Heated Washer Solvent, 2X Remote Trunk Release,
Turn Signal Mirrors, Center Console Courtesy Lamp, Rear Outboard Heated Seats, PVD Chrome 18" Factory Rims, Upgraded
Carbon Fibre Appearance Interior Trim, Highly Modified Main Body Harness, Instrument Panel, Door, Door Panel & Headliner
Wiring Harnesses, Custom Fuse Box & Tire and Loading Information Decals, Additional Acoustic Insulation[/size][/color]
- dpnewfie
- Posts like an LN3

- Posts: 598
- Joined: Thu May 22, 2008 8:01 am
- Year and Trim: 2005 GXP
- Location: Conroe, Texas
Re: Water in Car
2012 CTS-V Coupe, 4k miles and counting.
2005 Bonneville GXP, 200k and SOLD!J Wikoff wrote:It has been an honor and privilage to have been serviced by you.
-
ddalder
- Resident Gearhead

- Posts: 2599
- Joined: Wed Apr 01, 2009 7:11 pm
- Year and Trim: 2004 GXP, 2008 STS, 2020 XT6
- Location: Alberta, Canada
Re: Water in Car

Bose Luxury Sound System w/Touch Screen Navigation, Addition of Factory XM, 2005 MY Antenna, OnStar Upgrade (3G),
RainSense Wipers, Backup Camera, '00 Style Door Panel Courtesy Lights, Heated Washer Solvent, 2X Remote Trunk Release,
Turn Signal Mirrors, Center Console Courtesy Lamp, Rear Outboard Heated Seats, PVD Chrome 18" Factory Rims, Upgraded
Carbon Fibre Appearance Interior Trim, Highly Modified Main Body Harness, Instrument Panel, Door, Door Panel & Headliner
Wiring Harnesses, Custom Fuse Box & Tire and Loading Information Decals, Additional Acoustic Insulation[/size][/color]
- Bvill_GXP
- GXP Member

- Posts: 247
- Joined: Sun Jul 05, 2009 6:17 pm
- Year and Trim: 2005 GXP
- Location: Greenville, SC
Re: Water in Car
After about 2 weeks of owning my 05 GXP i would notice a wet type of feeling after it would rain.. so i figured it was just how the car was, so after a huge rain storm i got in the car and pulled out the drive way and stopped at the mail box and water start to pour in from the sunroof/garage door button area. So i was like wtf!!! So after getting out and opening the sunroof to inspect it i turned out that the drain plugs was stopped up. So about 2 days later at work i used the air hose and blow out the 2 front drains and them poured water in the channel to see if it would go down and it did in both front tubes.. I didn't have a flash light to look at the rear tubes to put the long air adaptor back there to blow it out.. But Yea the 2005 GXP stops up still!!! I'm just happy i didn't have to take it in for warranty work on the sunroof on a car i hadn't even paid the first months payment on yet!! but even if the GM dealership closes up I got a 45k 5 year bumper to bumper warranty from the Toyota dealership i got the car from.
2005 Bonneville GXP Fully Loaded


- CMNTMXR57
- Certified Bonneville Nut

- Posts: 5841
- Joined: Wed May 13, 2009 10:45 pm
- Year and Trim: 2006 STS-V, 2004 GTO, 2009 G8 GT
- Location: CHICAGO
Re: Water in Car
I just drilled two small holes in my spare tire well in the trunk (in the lowest section, almost like pinholes). They're not noticeble and I have no problems with water anymore. It'll leak down the internal drip rails, into the trunk, and out to the ground.

Retired Bonneville Owner and former GM Tech:
2004 Pontiac Bonneville GXP: Black/Ebony *SOLD*
Summer Toys: Combined 827 RWHP / 877lb/ft RWTQ
2004 Pontiac GTO: Impulse Blue Metallic/Black/M6: lots 'o mods, 415 RWHP / 405lb/ft RWTQ!
2006 Cadillac STS-V: Light Platinum Metallic/Light Gray/A6 - Spectre CAI, Magnaflow exhaust, Speed Inc. tune, 412 RWHP / 472lb/ft RWTQ
Daily Drivers:
2019 Chrysler Pacifica Limited: Mommy's new RGC
2015 Chrysler Town & Country Limited Platinum: Kids new RGC
2011 Camaro SS
2009 Pontiac G8 GT: L76, Sport Red Metallic
2004 GMC Sierra 2500HD: Victory Red - 8.1L Big Block and Allison
2003 Chevrolet Suburban 2500: Doeskin Tan - 8.1L Big Block... RIP
1999 Chevrolet Suburban: Sunset Gold Metallic - RIP

