Water leak passenger side?


Active LVC Member
Dec 31, 2011
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In the heavy rain this week I noticed a water leak on the passenger side floor that appears to be dripping down onto the foot slope and then pooling on the right corner of the floor. Any idea from where this is coming? Can it be stopped from the engine compartment side?
It's most likely coming in through the fresh air inlet under the passenger side cowl and running down the inside of the firewall to the floor.

I posted something at the other site that has a few pics of the inlet and so on here. Since I wrote that post, I've come to believe that removing and resealing the inlet mouth is pointless, and the real culprit is water running down the windshield, under the cowl panel and directly into the mouth of the inlet. There's a foam strip on the bottom of the cowl panel that rests on the lower edge of the windshield right above the inlet. One of the pics shows it. I think that foam is where the water runs under. The foam on mine was still in decent shape but the adhesive had gone bad and the edges were peeling off. That needs to be replaced or re-glued. If you're replacing, just make sure you use closed-cell foam, not open cell.

An even better option would be to put some sort of shield over the top of the inlet which is open on the sides, which would keep the water from running right into the mouth of it. One thing I've been meaning to try is cutting up one of those poly binders you get in the office supplies and strapping it onto the inlet like an upside down U. I have no idea if it'll work as I haven't had time to try it yet.
Mine does that sometimes as well. As a matter of fact, I believe that would be the reason why my blower motor sometimes doesn't work after it rains since the motor and relay are situated directly underneath where I assume the water leaks and falls on top of one or the other.

Seems like a simple with some silicone or other sealant to glop around the fresh air intake.
This thread is three months shy of 5 years old so I am going to hi-jack it. Every time I searched for passenger water leak, this thread came up. From the research I did on this and other forums, I would agree with Marcus. Here is what I had on my passenger floorboard after a decent rain.

My cowl had only 1 screw out of the FOUR that should have been holding down the cowl. My car is a 1998 so it is 18 years old but well cared for. I took the cowl off and noticed the air inlet was only slightly cracked on one side and appeared to be the original seal. I had some black caulk that was opened and needed to be used anyway so why not take off the air inlet and see? I started to pry the air inlet off.


As Marcus mentioned above, there was nothing of interest inside the air inlet. Now I couldn't see well inside but nothing jumped out at me. From research I learned there is a foam strip underneath the cowl that I thought would be disintegrating and needed to be fully replaced. I also knew I would need to keep that cowl pressed tightly against the windshield. I ordered the clips and screws. The clips and screw closest to me while I took the picture are the original (or at least what came out of the car) and the others are the new pieces.


Once I took the cowl off, I discovered the foam strip was in good shape but the problem seemed to be it shrunk and moved downwards over time. The loose cowl along with time I feel allowed the foam to move thus water could run to the bottom of the windshield then onto the metal where that foam should be and 'bam', into the air inlet. If your car is standing in place like mine was while at work, all that water simply runs down into the inlet.


I took some black caulk, taped it down and kept pressure on it overnight. The next day the foam was where it was supposed to me. I test fitted and didn't need the foam I bought but I cut some pieces and placed it just below the windshield as an extra buffer. If water does get past the factory foam, I have a bit more just past it. It may work, may not. Too soon to tell until the next serious rain. Here is a picture of the foam I ordered but it is too narrow to use if I were to replace the original. For you people out there in Mark VIII land needing to replace the foam, I suggest getting a size twice as wide as what I did. The thickness was the right size though.

I put it back together with the new screws and clips (no pictures) and I will let you know if I have rain water in the passenger area.
Mine was leaking due to a faulty seal at the base of the windshield corner; replaced the trim piece and the leak stopped.
FOLLOW UP: This weekend we had rain both Saturday and Sunday. Light in morning Saturday and nothing the rest of the day. Saturday night I checked the car and all was fine. Sunday it started raining about 10am and went on and off all day. Light to medium rain is as hard as it came down but long enough to get the floorboard wet if the problem had not been resolved. I am happy to say that my carpet was dry when I checked last night and again when I drove my lovely Mark to work this morning. :)
I have a problem with my LS leaking coolant on top of the tranny near the firewall. Water drips down the side of the tranny. I live up hill. Any suggestions?
You would probably have better luck asking other LS owners in their forum.

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