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Water in my car

About a year and a half ago I purchased a 2007 Chevy Malibu. So far I have been very happy with my car; unfortunately during the recent winter storms here in Arizona I have been finding water on the flooring behind the driver’s seat. It only appears there, I have found no evidence of leaking from the doors or sunroof and avoiding driving through water doesn’t seem to make any difference. I love my car, but this is driving me crazy!

Clogged sunroof drain tubes could be the culprit. Clogged door drains, clogged HVAC drain, and leaking rear window seal also come to mind as possibilities. How’s the trunk seal? Has the car ever been in a crash?

I’ve checked the trunk seal already and it’s never been in any sort of collision. I will check the other drains, thx for the suggestion. Unfortunately we are nearly at the end of the winter rainy season, so I won’t know if it’s fixed until summer monsoons

You can use a water hose to find the leak. Just have a couple of people inside the vehicle to let you know where the water is coming in. I’ve done this numerous times and it almost always works.

I’ve poured a few pints water in the sunroof drains and the floor is dry. Should I try to find something soft and ridgid to thread through the drain holes? I’m having trouble seeing the rear drain holes, it’s pretty sunny here. Also, I read something that says it could be caused by a breach in some sort of moisture barrier. Any thoughts?

Brett, I Know That GM Had A Couple Of Models Over A Couple Model Years Of Large Cars That Had Leaks At Breached Moisture Barriers.

They put out TSBs (Technical Service Bulletins). I see none so far that pertain to your Malibu.

The bulletins instructed technicians to check the door nearest the leak. Between the interior door trim panel and the steel door “shell” there is a vapor barrier (a molded translucent plastic “sheet”). When rain water enters the insde of the door through the window slot “wiper” strips the barrier keeps the water in the shell so that it drains out the bottom. It is normal for water to drip out the bottom of a door outside of the door weatherstrip seal.

The barrier is sealed to the door with butyl ribbon all the way around. It’s gooey and seals it quite well, but breaches were developing in spots at the bottom allowing water to drip from the interior trim panel and stream into the car’s floor.

After a heavy rain or after a heavy hosing check the bottom edge of the door trim panel for any water drops or evidence of where water was dripping. Touching along the bottom with a tissue might help. Also check the plastic sill plate (scuff plate) that runs under the door. It should be dry.

It may be worth looking at. Should that be the source of the leak, the trim panel can be fairly easily removed and the barrier re-attached.

Sometimes these leaks are dependent on the slope of a driveway or parking area and which way the car parks. Backing in may make a leak better or worse, but it shoudn’t leak anyhow.
Keep in mind that gravity will make the water travel to and accumulate in the lowest areas, sometimes not right at the source.


The sun roof has a drain at each quarter. If it is parked one direction it may leak, but not the other. You can try pouring water into each corner drain.

To clean the drain, most people suggest using string trimmer line from the garden center. Be careful as you can damage the drain if you are not careful. Other people suggest using compressed air, but remember to take it easy on that as well as it also can cause damage.

Good Luck