I get why you’d want to reach for silicone caulk—easy to find, cheap, and it works for a ton of stuff around the house. But for cars, I’d be careful. Regular silicone doesn’t always play nice with rubber seals or painted metal, and it can get messy fast. I tried it once on my old Civic’s trunk and it just peeled after a couple months.
There’s specific automotive seam sealer you can grab at auto parts stores. It’s a bit more expensive but actually holds up to the flex and temp changes. If you do go the silicone route, make sure it’s the clear, outdoor/weatherproof kind and test a small spot first. Prep is key—clean and dry the area, scrape off any old gunk, and mask around the spot unless you want a sticky mess everywhere.
Honestly, sometimes the leak is coming from somewhere totally unexpected, like a cracked tail light gasket or even a clogged sunroof drain. Worth poking around before you start sealing everything in sight.
That’s a solid rundown. I’ve seen folks slap silicone on just about everything, but you’re right—it rarely lasts on cars, especially with all the flexing and temp swings. Seam sealer really does hold up better, even if it costs a bit more. And yeah, leaks can be sneaky. I once chased a “window leak” for weeks before realizing it was the third brake light gasket… go figure. Good reminder to check all the usual suspects before breaking out the caulk gun.
leaks can be sneaky. I once chased a “window leak” for weeks before realizing it was the third brake light gasket… go figure.
That’s a classic. Had something similar with my old Tacoma—swore it was the rear window, only to find water sneaking in through the taillight housing. It’s wild how many places water can find its way in, especially after a few winters. I’ve tried silicone too, but yeah, never seems to last with all the flex and vibration. Seam sealer’s pricier but worth it if you don’t want to revisit the same leak every spring. Funny how sometimes it’s not even the window at all causing the foggy mornings...
Funny how sometimes it’s not even the window at all causing the foggy mornings...
Totally been there. I chased a “leaky window” in my old Civic for months, only to find out it was actually creeping in around the antenna base. Never would’ve guessed. And you’re right about silicone—seems like it always peels off after a season or two, especially with all the flexing and temp swings.
Seam sealer’s a step up for sure, but I’ll admit, I’ve had luck with a cheap trick: picking up those little moisture absorber packs (the silica gel kind) and tossing a couple under the seats. Doesn’t fix the leak, obviously, but it really helps keep the glass clear in the morning while you’re figuring out where the water’s getting in. Not a long-term solution, but it saves you from scraping fog every day.
Funny how you think you’ve sealed everything up, then you get that one wet patch on the headliner or carpet and realize water’s got its own secret path. Never underestimate how sneaky it can be...
That’s a good call on the silica packs. I’ve tossed a handful of those under the seats too, and they definitely make a difference when you’re just trying to get out the door without wiping down every window. The weirdest spot I ever found water sneaking in was actually through a taillight gasket—never even crossed my mind till I pulled up the trunk carpet and found it soaked.
I hear you on the silicone. It’s like, you do all that work and then a few months later, it’s peeling up or cracking, especially if you park outside. Have you tried those little rechargeable dehumidifiers? I got one for cheap and just leave it in the car overnight. Not perfect, but at least it’s reusable.
Honestly, tracking down leaks feels like chasing ghosts sometimes. You think you’ve got it, then there’s another damp patch somewhere else. Makes you wonder how much water can really sneak in without you noticing...
Funny you mention the taillight gasket—had almost the exact same thing with my old Civic. Water would pool under the spare tire and I couldn’t figure it out for ages. Ended up using a smoke pen to track air leaks, which actually helped spot a tiny gap in the trunk seal too. I’ve tried those rechargeable dehumidifiers but found they only make a dent if you’re already pretty dry inside. Honestly, I think half the battle is just keeping your floor mats dry—those rubber ones are worth every penny in the winter.
I’ve always wondered if those little silica gel packs you get in packaging could do anything for car moisture. I tossed a bunch under my seats once, but honestly, didn’t notice much difference. I’m with you on the rubber floor mats—they’re way easier to dry out than the carpet kind. Has anyone tried just leaving the windows cracked a tiny bit overnight? I’m never sure if that helps or just lets more damp air in.
Leaving the windows cracked overnight is a bit of a gamble, honestly. If the air outside is damp, you’re just inviting more moisture in—kind of defeats the purpose. I’m all about maximizing efficiency, and those silica packs aren’t really up to the task for a whole car interior. Rubber mats though? Total win. Less hassle, less energy spent drying things out. I’d rather run the defroster for a minute than risk soggy seats from an open window...
I hear you on the cracked windows thing—not my favorite move either, especially when it’s muggy out. I’ve seen folks try the silica packs and even kitty litter in socks, but honestly, if your car’s got a real moisture problem, those tricks only go so far. Rubber mats are a solid call though. I swapped out my old carpet ones for rubber a while back and it made a bigger difference than I expected, especially after tracking in snow or rain.
One thing I’ll add is making sure your cabin air filter isn’t clogged up. If it’s dirty, you’ll get more fog and musty smells inside. Swapping mine out took like ten minutes and helped with the morning fog. Also, if you’ve got time, cracking the windows just a hair right after driving (when everything’s still warm) sometimes helps dry things out faster—just not overnight.
Running the defroster for a bit in the morning is probably still the easiest fix, though. Not always fun in winter but beats sitting on damp seats...
I get the appeal of blasting the defroster, but honestly, it feels like overkill most mornings. Isn’t that just wasting gas and energy, especially if you’re idling for 10 minutes? I started using a small squeegee on the inside of my windshield instead—takes about 30 seconds, no fog, no waiting around with the engine running. Maybe not as cozy as a warm car, but way less wasteful. Anyone else tried going low-tech like that?