Car Question, What is this?

So here’s the thing:

(Let me preface this by saying I don’t drive, and am very much outside of the entire car culture thing, so I won’t be exactly a font of imformation, but I’ll try my best.)

Car in question is an Oldsmobile Ninety-Eight, 1991 (could be 92 or 93). Suddenly, one day there is a big puddle of water soaking the floor mat in the footwell behind the drivers seat. We actually thought the dog had peed in the car, but soon realised that wasn’t it-way too much liquid.

So the SO thinks it’s a whole in the wheel well, water is splashing up and getting in and running to the lowest spot. He takes the car to a dealer who promptly announces that his diagnosis is incorrect and that the seal on the back windshield is to blame. And it does look like it might be leaking.

Takes the car to a guy who only does windshields (everyone agreed this was a good idea), who promptly announces it is not the rear windshield, but probably the side window leaking. Mind you, he didn’t offer any suggstions other than to wait until it dried out and use the hose to confirm this is where the leak is. He actually said most people just live with it(?).

It’s the spring and very rainy here and I’m sure this will ruin the carpeting, and possibly make the car smell. I’m going to great lengthes to soak the water up and get the carpet dry but it’s an uphill challenge.

How about it? Anyone else out there have any guesses as to what this might be?

All guesses entertained, don’t be shy. It’s not like he’s likely to listen to me anyway, but it is making me curious.


I had a car with the same problem. I just dried the car after every rain. Yes it dig meldew, but in 6 short months it was summer again. :slight_smile:


This is probably way off, but could it be a leaky heater core? I only suggest this because this has happened to my Toyota Corolla. In my case the water leaked down through the dashboard and onto the carpet, but the wet spot was concentrated on the floor board in frontof the driver’s seat.

Would it be possible for liquid to run from the dash and under the carpet to the “low spot” on the floor of your car? Was any of the carpeting in the front of the car affected?

If so, check the coolant level of your radiator to see if the leak might be coming from there.

Another culprit could be the air conditioner. If you are running the AC (I know we are using ours in Mississippi!), there is a drain under the dashboard, usually around the passenger’s side. This drain serves to dispose of water which has been removed from the air due to condensation on the cooling coils. If the drain tube is stopped up, the water will puddle up in the tray, stream down the inside of the firewall, and seek the lowest spot it can get to.

My first instinct was the heater core. If it breaks (the age of the car is right too) it’ll leak liquid into to heating vents, and they’ll direct the flow of water to the interior where they come out. It can be alot of fluid. The question is, is it realistic that the liquid could flow from under the dash, possibly via the heat ducts, to behind the drivers seat. The heating core is typically behind the Passenger dash, beneath the glove box. There is more space there considering the driver controls.

Otherwise a leaky window is a definate possibility, but I’d think the water volume would be minimal unless it is being funneled into the car.

What does the liquid smell like? Heaters smell like radiator fluid cause they use it.

It’s definitely just water, trust me, I’m the one doing on the sopping up. Even though it poured like a monsoon over the last two days not that much water accumulated. What’s with that?

And it’s only that one footwell that gets any water, the front footwell is unaffected. Today it wasn’t completely soaked the area that was the wettest was the right hand corner closet to the driver’s seat.

I got no ideas, let me know if you need more details, happy to provide them if I can.

*Just pound a nail through the floor of the footwell (and take the nail out). Now you have a drainage port.

Worked for me when water would collect in the trunk of the old '75 Impala.


The car’s name was Vlad. Get it?

Not really a hijack but I just wanted to say that everyone I know who has had an Oldsmobile has had this happen sooner or later–I was starting to think it might be me! I used to have a 1986 Oldsmobile Calais and it did it too.

Anyone else?

In my '88 Chevy, much the same happened to the front passenger’s side. It was the seal around the windshield, but the water leaked into the car between the inside and outside of the roof, then drained into the car from the plastic molding above the side window. This could well look like a side window leak, but fixing the windshield fixed the problem. Also knew someone with an old Buick that had the same problem, only the leak manifested itself from the rearview mirror attachment on the roof.

As a side note, I was told by an amateur do-it-yourself car person than I that the big culprit in causing the seals to leak was winter weather (presuming you live in a cold climate). Indiscriminately scraping snow (and especially, frost) off the windshield with a hard scraper damages the seals, and road salt further dries them out if allowed to accumulate - not to mention the contraction caused by the cold weather. He suggested using the defroster exclusively plus a brush for snow, or at least being careful to avoid the edges of the windshield with the scraper.

I’ve seen the same symptoms before and it was the rear window seal.

The only way to know for sure though is to use the hose around the edges of the rear window. Do this when you have already dried out the carpet, so that you will be able to detect the first hint of moisture returning. If it turns out not to be the rear window, try the hose all over the place, but only one spot at a time, until you detect water collecting on the carpet again.

My bet is still on the rear window seal though. Unless of course you have a sunroof, in which case my bet is on that.