Leaking on passenger side floorboard

Afternoon gents, it seems as though my son's car has some kind of leak on the passenger side and is pooling in the floorboard. Luckily we have weathertech type mats that hold the water but I would sure like to know what is causing this. I remember seeing some type of bladder thingy on the firewall when we were installing his cams. I'm like what the crap is this thing so I touched it and water came gushing out. I figured it just collected runoff from the wiper area and leaked out when it got full. Lately we have been having torrential rains here so we checked his floorboard this morning and sure enough it had about a pint or so of water in the mat. Opened the hood and touched the bladder again and seemed like a gallon spewed out.

So what is this thing and what else can I look for as the cause of the leak? Luckily none of the wires I side seems to be wet but there is water on the inside firewall.

Definitely vent hole plugged- pull the plastic trim off under the hood below the window and clean it out- You will hear the water draining underneath the car when the hole is free of debris


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Long known issue with this model. Plenty of threads abound

Cool thanks. Got it cleaned out

Simple fix. The Cowl drains get clogged. Just remove them. When they get clogged the water goes right into the Cabin Air Filter Box. Very common issue. Can really create some electronic havoc also. That fuse panel on the passenger side kick panel is the smart junction box. Controls a lot of accessories in the car. When you put everything back together also replace the filter.

You might want to pull the carpets up (you'll want to remove the seats on both sides) to check the floors underneath. Depending on how long it has been going on you may have some rust to deal with. Better to look now than be surprised later.

86GT351 said:

Cowl drains

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- Didn't even know these existed. There is also one on the left side. Neither of mine were clogged, but when I checked the left, a white/clear plastic plug or tube end fell to the ground.

You can leave them in place so the water doesn't run down the firewall. After I wash my car, while they're all wet, I just reach in there and pinch the rubber so that anything in there comes out. There's one on each side.

If clearing those drain plugs doesn't resolve the issue, check for the TSB regarding this common issue with the 05s through some of the 07s and 08s. The leak identified in the TSB drains down the inside of the front passenger kick panel where the SJB (Smart Junction Box) is located. Eventually, the contacts on the SJB begin to corrode and result in numerous electrical gremlins.

This is a very known issue with the S197. I see it all the time, esp on FB, people asking about water getting into the car. I went through this myself and it almost destroyed my SJB. I have attached a PDF explaining how to water proof the car. I also suggest wrapping the SJB in a plastic bag so it doesnt get wet and shorts out or corrodes.

Excellent, finally able to see the likely water entry points for the cowl, doors and wiring harnesses. (last pg).

DieHarder said:

Excellent, finally able to see the likely water entry points for the cowl, doors and wiring harnesses. (last pg).

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You're welcome!

One thing I did after my first passenger floorboard flood, was punch out the rubber grommet to make the drain hole larger, thereby less likely to clog with debris. Haven't had any issues since, been about 5-6 years

I had same issue, no flooding since drain unclogged, been three years

I had this happen to me, cleaned that out and it didn't fix it. My issue ended up being the seal above the glass on the passenger door, so if you notice it leaking again check that se out.

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rdsx18 said:

I had this happen to me, cleaned that out and it didn't fix it. My issue ended up being the seal above the glass on the passenger door, so if you notice it leaking again check that se out.

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If it seems better then maybe you want to remove the injectors and have them professionally cleaned and flow tested.

Just how are the fuel injectors related in anyway towards the passenger compartment leak issues caused by the seal above the glass on the passenger side door?

06 T-RED S/C GT said:

Just how are the fuel injectors related in anyway towards the passenger compartment leak issues caused by the seal above the glass on the passenger side door?

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Lol I posted an update on my thread about starting issues with my car, they must have got them mixed up. I'm on Tapatalk but my comments are in the right threads from what I can see.

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Thanks for clarifying

Here are two of the three most common water entry points and how I fixed them.
First I add aluminum screen on the backside of the cowl cover, this keeps out the leaves and small seeds that fall of the trees next to my driveway, then I removed the deteriorated foam gaskets under the cowl snap locks on the cowl and used seam sealer to glue them back in place. Last thing I did was to use a rubber gasket sealer stuff to seal around the top door seals.
Here's some photos of what I did. One last thing. You still have to clean out the rubber grommets at the bottom of the cowl in the engine bay from time to time.