Mechanics

CAN'T FIND THE SOURCE OF INTERIOR LEAK

1999 Pontiac Grand Am • 120,000 miles

I have a 99 pontiac grand am, and the rear passenger floor is always totally soaked. I really don't see where it comes in from. There doesn't seem to be any leaks from the door at all, and from what I can see theres nowhere underneath the car that it could be coming from. Also, my driveway is on an incline if that makes any difference.
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Dgriffin123
January 10, 2012.




Also, my trunk has water problems as well. It had several inches of water in it at one point, the spare tire was totally underwater, so I punched a small hole in the bottom of the trunk to let the water drain out.

Tiny
Dgriffin123
Jan 10, 2012.
Some have reported the spoiler mounts in trunk? Someone also suggested door is not draining properly and then overspilling into car.

Tiny
Fixitmr
Jan 10, 2012.
And this was reported. All Pontiac grand prix from 1999-2009 that leak water on passenger floor is from the following: The front cowl panel, [Where windshield wipers are] Has a air box inside the panel, That when built has a two piece construction that is sandwiched together at factory, and over time, summer heat, Icy winters etc, dries out and allows water to get into air box and drip out below dash on passenger side. To fix: Remove wiper arms, remove cowl screen, and you will notice a box looking square on passenger side, Clean out in and around box opening top. Must be clean and dry. Next use ether urethane windshield sealant, or silicone water proof sealer. Reseal all the way around box, [Where metal body meets air box.] Make sure to re seal all the way around air box and let dry overnite. You can buy ether sealants at your local automotive parts co.

Tiny
Fixitmr
Jan 10, 2012.
Awesome, I'm gonna go check that out right now. Thank you for the quick reply!
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Tiny
Dgriffin123
Jan 10, 2012.
It comes from the front cowl area. Open the hood and look for any lose rubber gromets on the firewall. Remove the under dash panels then pull the carpet back on both sides. Which side is wet by the firewall?It leaks in and rolls back to the rear behind the front seats. Have a helper spray down the firewall. You stay inside and look for waterleaking in. These leaks maybe from a split seam also. Remove the trunk carpet then get in the trunk with a flashlight. Let your helper flood the trunk out. You should see no light coming through anywhere. Check the l and r trunk hinge area. Then check for a leak at the wheatherstrip. Youll find them keep looking. Youll need to strip out the interior to dry the carpet to get rid of that smell.

Cadieman
Jan 21, 2012.

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