How do I deal with repeat flooding in my Toyota Matrix?

June 8, 2009 12:22 PM

Help -- my Toyota Matrix is flooding in behind my passenger seat. What should I check? What are the reccomendations of the hive mind? Details below.

Last weekend, I noticed that there was water behind and under my pasenger seat, seeping forward. There were water bottles back there, so I thought one must have leaked and cleared them out and dried out the mess. Whenever I was in the car and it was not raining I opened the windows to try to dry out the mustiness.
Fast forward to this weekend. Lo and behold there is a puddle of water behind my passener seat again. It has been raining all week and I have been religious about keeping the windows closed. There is no sloshing in the doors. No apparent holes in the roof. Where could this water be coming from? Is there a way to figure out if there is a hole in the undercarriage without getting under there?
We are expecting more rain this week and I fully plan to check everyday now that I know this was not just an issue with a stray water bottle!

posted by Librarygeek to home & garden (18 comments total)

Does the rain correspond with the flooding or not?

If it has rained, then obviously a leaky sunroof, but failing that, it's probably a bad seal on one of the rear windows. Also, if one of your doors is damaged, water can seep in past the weatherstripping. The problem with leaks like that is the entry point may not be directly above where you're finding the water.

If it hasn't rained, it's probably a clogged drain on your air conditioner. Any reasonable mechanic should be able to sort either one out.
posted by electroboy at 12:31 PM on June 8

I second the weatherstripping on the doors. I've had problems with the weatherstripping on my Toyota Camry trunk after a minor car accident. The weatherstripping was inadequate causing a leak.

The water kind of trickles around the chassis of the car and flows underneath the plastic and carpet. It's usually hard to detect this kind of a leak and unless there is obvious visual damage to the weather stripping, you might need to take a look at other Toyota Matrix cars and compare the seals.
posted by abdulf at 12:39 PM on June 8

Are you sure that the water is coming from the rear? Most cars carry engine coolant into the cabin for the heater, and the hoses can often leak. If it's leaking down the firewall, it could be running under the carpet. Check your engine coolant level and smell the fluid to see if it smells sweet.
posted by TheNewWazoo at 12:46 PM on June 8

Another vote for weather stripping (the door seal) on the doors. I've had this happen on three different makes of cars. Might also/otherwise be the seal around your rear passenger side window.
posted by dowcrag at 1:03 PM on June 8

Door weather stripping, or rear window seal. Is the trunk floor wet, too? If so, the trunk seal is suspect.

With the door or trunk, clean the rubber and the contact surface, and then hose it down to check.

If you cannot dry in the hot sunshine, use a fan or floor heater to dry out the interior of the car. Soon, before the mold grows.
posted by Midnight Skulker at 1:17 PM on June 8

I'm gonna be the contrarian here and offer another suggestion: have you been running the AC all week as well? It's possible the drain for the AC unit has clogged and you're getting water from that. It happened to me in my old Subaru Outback. Whenever the AC was running for an hour or so and I took a sharp turn, it would slosh water everywhere. It's a simple fix, just cost me the lift fee to get it done.

Based on the fact that it's raining though, it's probably the stripping ;)
posted by teabag at 1:33 PM on June 8

Rust at the base of the windshield is another possible culprit. Water goes downhill; where you find it isn't necessarily (nor even likely) where it came in.
posted by TruncatedTiller at 2:17 PM on June 8

Checking the car daily as it rains would certainly help correlate the water with a leak of some sort, but might not help if you don't see where the water is coming in. I'd probably sit in the car while a friend or neighbor squirted it with a hose. If you don't have a garden hose, you could take it to the car wash.

On a slightly related note, my SO's Chevy Trailblazer once had a leak in the line that ran winshield washer fluid to the back window. If your car has one tank for both front and back wipers (assuming you have a back wiper), that could be a possibility too.
posted by youngergirl44 at 3:33 PM on June 8

Do you have a sunroof? Sunroof drain pipes clogging or fracturing are often causes of leaks.
If you park under trees, you could accumulate leaves in A/C drains (where the condensation drains out) and cause other clogs that might cause water to flood in under the cowl (the area directly below the windsheild).
It might be worth sitting in the car and having someone systematically hose the car down (starting from the top, of course) to see if it's something you can fix yourself.
However, the water might be showing up behind your passenger seat, while really coming from somewhere else. When I diagnose a leaking car, I take all of the seats and carpets out so there's no chance of water leaking in behind the carpet where I can't see it.

Take it in before it gets worse. Water infiltration gets really expensive. I've replaced and rewired many a control module that have fallen victim to corrosion and water damage.
Also, your carpet will retain water like a giant sponge and will rust through the floor pan of the car. Lots of wiring is run under that carpet, too.

If you're just noticing the leak, you're still at the cheap stage of things where a new door seal or unclogging an A/C drain will fix everything. Don't live with the leak, because leaks turn into floods
posted by Jon-o at 3:56 PM on June 8 [1 favorite]

Another potential culprit is the car's cowl (if it in fact, has one.) Mine got warped or some such, and as a result I got water in the passenger seat floor area every time it rained. From the Car Parts Wholesale website:

The cowl is an automotive part responsible for supporting the windshield and the dashboard. It is located just below the windshield specifically between the engine firewall and the front of the dash panel. In some European countries, the cowl is being referred to as the scuttle or cowl panel as a whole. Looking at the front of your car, you will become aware that the cowl is just behind the hood or the area between the hood and the windshield.

You will also notice that cowls usually has a visible vent that allows air into the engine compartment and some parts of the car's heater-ventilation air conditioning (HVAC) unit. This vent has air filters to regulate dust and other particles that enter the vent together with the air. Cowls are also extended until underneath the hood, providing a place for some components of your vehicle's HVAC system and serving as the windshield and its wipers base.

Was a pretty inexpensive fix as I remember, and the dealer was not at all surprised to find it was the culprit. Good Luck.
posted by Rewind at 4:19 PM on June 8

Wow, tons of good thoughts for things to me to look at.
I do not have a sunroof, I should have mentioned that.
If I take it in, how hard is it to diagnose something like this?
posted by Librarygeek at 4:51 PM on June 8

I was also going to suggest a loose a/c hose. That happened in my Taurus. I was taking a trip and running the a/c so much that it was sloshing around before I realized what was happening. It seemed to short circuit my speakers too. Turned out that the hose that was under the rug on the passenger side had popped out.
posted by saffry at 5:23 PM on June 8

The sun roof on my Matrix leaked, but it wasn't obvious that it was the sun roof - the water seemed to be coming from the top of the front passenger door. It turned out that small debris (dander and fluff from trees) had clogged up the drainage holes in the sunroof, which was causing water to backup and eventually flow over to near the top of the window. Open up the sun roof, and check that the drainage paths are clear.
posted by skwm at 5:42 PM on June 8

Well, this diagnosis can go one of two ways:
1: They hose the car down and the leak is obvious or clear the A/C drain and let the water out and it's quick and easy.
2: They have to take the whole interior out and it takes a couple days.

There's always the possibility that this is something that's fairly common on the Matrix and the Toyota dealer might be able to hone in on the problem pretty quickly.
If the water has caused any serious damage, it's not unusal for insurance companies to cover some of the cost as flood damage. If it's starting to get expensive, give them a call and see what they can do for you.

Don't worry, this could still be at the phase where it's quick and cheap and the only damage will be a musty odor.
posted by Jon-o at 5:58 PM on June 8

This happened to me - it was (bizarrely) the drain holes for the rear doors. They had clogged up and filled the rear doors with water (presumably down the window seals) and spilled over into the car. The weather stripping around the door actually helped it stay in! It filled the door cavity up first, then leaked across.

At the bottom of the door (most likely near the back) will be a slight hole around the seam. Poke a small piece of wire in there. If a long length (like 2 inches or more) goes easily in, then you're fine. If you have to shove around a bit and then water and dirt comes out, you have fixed your issue!

I found this, incidentally, by hearing water slosh when I opened the rear door. I noticed the initial problem when I braked and got wet feet...

Try this and see how you go, as its easy enough to do yourself.
posted by Brockles at 6:34 PM on June 8 [1 favorite]

We had this exact same problem some years ago in a Volkswagen Passat, and it turned out to be the air conditioning. (In our case the a/c drain had never been connected at the factory.)
posted by ook at 6:59 AM on June 9

If I take it in, how hard is it to diagnose something like this?

Should be pretty easy. If you have a dealership you trust, they've probably seen it before or have gotten a service bulletin on it.
posted by electroboy at 7:42 AM on June 9

Thank you everyone. I have called the local dealer and the car is scheduled to be looked at on Monday. I really do appreciate all of the responses. I was able to better explain the issue after seeing what information I left out of my request here. Also, the responses help give me an idea of the kinds of things that might be wrong. This makes me feel like I am going in with my eyes open, knowing what to expect and that maybe I won't be ripped off :) Crossing fingers that they can find and fix this quickly! FWIW, my partner didn't hear any water sloshing. From the last 2 times, I can tell the problem is starting in the back passenger area. (I was able to see a puddle there and the front was still dry.)

Thanks again.
posted by Librarygeek at 2:40 PM on June 11