Piston Slap: Good Rid-dance to damp carpets?

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Rory asks:

So in my infinite wisdom, I left the windows open on my 1992 Mitsubishi Montero while I was away over the weekend. It rained, so this is some bad stuff. I am going to get DampRid so that I can start to dry this out as soon as possible. Do you have any other ideas on how to fix my mistake?

Sajeev answers:

Ugh, I have been there. One time I left my 1988 Mercury Cougar’s windows cracked during a huge rainstorm, and the cabin was allowed to marinate for days before I approached the car and smelled the problem. This was pre-Google times, therefore I didn’t know about DampRid’s decades-long reputation of water absorption. So instead I cut out the affected carpet as a quick fix to the problem. (It was already sun bleached and in need of replacement, so cutting it up wasn’t a big deal.)

But that wasn’t a fix at all, as the water/mold damage affected most of the padding underneath the carpet. That’s the first half of my story, but I recommend yanking the carpets if you have any concerns about DampRid.

Rory replies:

I’m not gonna be able to pull the carpets out of the Montero, at least not immediately. I need this car for daily driving; it can’t be decommissioned for that long. The floor mats are out and I vacuumed it hard. Now I hope DampRid will do its thing.

Sajeev concludes:

I hope so too, Rory! Because if not, you must do what I did next: yank out the carpet and bolt back in the driver’s seat so its drivable, if a bit noisy. It’s shocking how quickly you can remove a vehicle’s seats, console, and rocker panel trim and make quick work of the moldy carpet. With little else but bare metal floors inside, I cleaned all surfaces with Lysol, sanded/painted a metal bracket under the carpet that became rusty, and bombed the rest of the interior with Ozium. Boom, it was done and the smell was history.

Not a photo of the actual event, but it does paint an appropriate picture. Sajeev Mehta

Problem solved, except I was driving around on a metal floor with one Cougar bucket seat for far, far too many trips to work/school. That’s because I first waited a few days for a color sample, then a few weeks for the correct “Oxblood”-toned replacement carpet to arrive. But that’s not relevant to you and your Montero, as I assume your carpet doesn’t need replacement, just a long time to dry out. Or not, as maybe DampRid isn’t a product with a misleading name?

Hagerty Community, do you think that will work, or does the carpet need to be pulled?

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    Sajeev, you are right of course right, once your carpet has been soaked, the only way to totally ensure that you get the floor dry is to remove the seats, carpet and padding. I’ve had to do this on more than one vehicle and I have learned that even if the carpet feels dry the padding underneath can still be damp/wet and once it gets damp it’s never gonna dry out…its more time and effort to do it correctly but it’s better to do it correctly than to lay away at night thinking about it…

    “…I cleaned all surfaces with Lysol, sanded/painted a metal bracket under the carpet that became rusty, and bombed the rest of the interior with Ozium….Not a photo of the actual event, but it does paint an appropriate picture.”

    I swear, Mark Twain couldn’t have said it any better. It elicited a chuckle outta me, anyway! 😉

    I’ve never had carpet/under-mat get quite this soaked and sour, I guess. Most of my rigs that forded streams and/went topless in rain only had rubber mats for floor covering. However, for “less-than-soaked” carpet from an occasional bit ‘o’ rain through an open window, I’ve generally used a wet/dry shop vac and Idaho’s notoriously low humidity to dry things out. I don’t know where Rory lives, but I know what kind of downpours happen in Sajeev’s Houston area, so I guess I can imagine that pulling the carpet/mat and replacing is an appropriate measure. Of course, you could always drive it up here to Idaho for a week, park it in my field with the windows down, and be assured that it’d be fine in a few days. Moisture/mold ain’t got a chance out there! As we say here in summer, “Yes, it’s hot, but it’s a dry heat”.

    I wish we had that low of humidity! Here in MS it’s so humid that a vehicle’s vinyl/leather/plastic surfaces will get mildew just from sitting even if out of the elements.

    Good point. If Rory lives in, oh I donno, Tucson right now (highs are well above 100) he can likely roll down the windows and let mother nature handle it.

    for 93 era GM products… you have carpet on a backing that will feel dry and trap moisture underneath. The layer (jute/fabric fluff??) underneath can be saturated with water. Sometimes there is an additional layer wrapped in plastic underneath the stringy material layer creating more moisture pocketing.

    Take the example of the GMT400 trucks, notorious for a screw in cowl above heater box allowing moisture in, water drain routes that back up if you don’t keep bottom of fenders clear and cause water to pool at sills, and window seals that let moisture in (if it isn’t the roof edge perforating, which it often does) and you have lots of chance of water under that dry carpet.

    If it smells or is moldy. Beware. I pulled up a carpet in a 93 truck this weekend and the damage was much worse than appeared from below. I wasn’t too surprised, at this particular truck had mold up the seatbelts and the seat brackets were so rusty the lower parts were disintegrating in my hands. Not a truck for a high schooler’s first project though.

    What you are describing is much like the factory carpet in my Cougar. Luckily mine was sun bleached, so I just gave up and threw it out.

    I would definitely be aggressive whatever you do. DampRid is good for boat and camper interiors that do not have active leaks. I seriously doubt you can fit enough damprid in that cabin to dry those carpets out. The longer the moisture stays, the worse the problems. If you get a mold bloom, you will get mold in places you cannot get it out, like seat foam, ventilation ducts, etc. Electrical system damage is the next concern, followed by rotting floor pans.

    Having an ‘84 Corvette and ‘86 300E both have water flow in under the doors due to bad Sacramento street flooding I did the following: Elevate the front of the car on ramps so you can force the water to pool in one area. Pull carpets loose and support carpet and backing above the metal floor pan. Vacuum up standing water and then vacuum water from carpet and backing. Place a space heater in the car with the windows cracked open for a day or so until dry – just set the heater so it doesn’t melt anything or get too hot. Worked fine without any residual smell.

    I’ve had good luck with pulling back carpeting where possible, using a shop vac to suck out as much water from carpet and padding, then grabbing the dehumidifier from the basement, placing it inside the closed car, and running it on max for a few days. Works wonders.

    Just under 2 years ago, I had left my windows down in the parking lot at work, when a freak storm blew through and thoroughly soaked my interior. Problem was, my family was leaving for a week vacation the next morning, and it was now predicted to rain on at least one of the days of vacation but be very warm on the others (was August). So, I grabbed 3 gallon-sized buckets of DampRid, put them inside, parked it in the garage (normally my wife’s spot, but we were taking her car on vacation), and rolled the windows all down, and put a box fan bringing in air to one front window, and another exhausting air on the other side from a rear window (zip tied the handles on the fans to the “oh Sh!t” handles of the truck, worked pretty good). Left them running all week and between the fans, DampRid, and warm temps the thing was bone dry when we came back and there has been no smell of mold in the intervening years, so with a little luck, a lot of airflow, and a bit of effort, it can be done.

    I remember, back in the day, having to pull the carpets, took bench seat out, needed to use the car so popped a milk crate in as a seat. Those were the days!

    I have successfully used a hair dryer left on overnight to dry the affected area to the bone, followed by an ozone machine for 6-12 hours to rid the car of any weird smells. Worked great.

    The padding would be my biggest convern. What you can’t see and what mystery it holds in terms of moisture or mold.

    If there was so much water that it was puddling up, your padding is shot. I tried pulling this stuff up on a fixer upper and found that parts of it had been glued down, so it separated as I tried to remove it. I’m certain that you need to pull out the carpets – damp rid isn’t going to do it. Do what Sajeev suggests and bolt a seat back in. Wet padding will lead to rust, mold and other problems if wiring is run under the carpet Just suck it up and do the job that you know needs to be done. There aren’t any shortcuts that will work for this.

    When my MGB was drenched on the return trip from VIR one year, (It only had a hardtop at the time, which was left at home.), enclosing a dehumidifier with the hardtop on and the widows closed did the trick.

    This is a bit of an old school hack that works very well.

    Take a 5 gallon bucket or similar, fill it 1/3 of the way with calcium chloride and park the vehicle in the sun all closed up and that will draw out moisture like you wouldn’t believe. Don’t fill the bucket more than 1/3 full though as it could overflow and defiantly keep a close eye on the water levels, checking daily would be my recommendation at least for the first few days.

    The LAST THING you’d want is for the bucket to overflow soaking your carpets with calcium chloride,,then you’d REALLY have a mess !

    I’ve used this method on boats for years that are shrink wrapped for the Winter and it really works well and is cheap to do. Way cheaper and way more effective that these ” mildew gas” bag type thingies.

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