How To Fix Common Interior Water Leaks (Info In Comments)

How To Fix Common Interior Water Leaks:

Water leaks are one of the most common complaints and problems with the Genesis Coupe. If your coupe is leaking, potentially causing heavy condensation or a moldy/mildewy smell inside, it is likely coming from leaks at one of these (or multiple) locations:

Tail light gaskets

This is the most common area to leak - probably 90%+ of Genesis Coupes have leaked or will leak from here because the foam OEM tail light gaskets simply aren’t very good. Water is channeled around the trunk opening and down the sides, causing it to run over the tail lights. If your tail light gaskets are leaking, you will notice water pooled under your spare tire, sometimes accompanied by a sloshing sound when driving. Once the trunk is completely full of water, it can slosh over and into the passenger compartment, typically soaking the rear floorboard and carpet in more extreme cases. Water can be easily drained from the trunk by pulling the rubber drain plugs – they can be left out to drain water as it gets in there until the problem is fixed, if needed.

There are a few options for fixing this:

• Replace the tail light gaskets with aftermarket polyurethane gaskets. This is the hassle free, one and done deal so you never have to mess with it again. ATQ is the only company making them. https://atqauto.com/lighting/tail-light-gaskets/

• Applying a thin layer of clear silicone sealant on both sides of the tail light gasket where the gasket contacts the vehicle, and where it contacts the tail light. Note: this can make it quite difficult to remove the tail lights in the future if you use way too much silicone.

• Applying a thin layer of silicone grease (aka plumber’s grease) in the same location as previously mentioned. This is less permanent, but a little messier if you have to remove and handle your lights more frequently.

• Applying a strip of tape across the top edge of the lights to cover the gap between the lights and vehicle so water flows over and not through it. This probably isn’t the best option, but it is better than nothing.

Sunroof components

This is probably the second most common cause of leaks. The seal around the edge of the sunroof isn’t actually watertight, so there are channels under the sunroof edges to catch water that makes it through - you can see these channels if you open the sunroof. At each corner, there is a drain tube that runs down the inside of each pillar, and to the bottom of the car near each fender. These drain tubes can get clogged with debris over time, especially if you tend to park under trees, and the water can’t drain out. When this happens, you might notice wet spots on your headliner, and sometimes it can run all the way down to your carpet.

Pour a little water near the drain tube in each corner, and a few seconds later it should run out from the bottom of the car in that respective corner. If it doesn’t, the tube is clogged and needs to be cleared out. Compressed air can be used to blast the tubes out from either end, and a length of wire can be useful for poking things loose if you don’t have access to compressed air. Additionally, if your drain tubes are clear and you only notice a wet spot on the headliner after sustained amounts of rain, the seal between the metal drain channel and the plastic end cap where the drain tube attaches is leaking. This can be fixed simply by applying silicone sealant where the two pieces meet. The headliner is only held in with plastic pop clips, just pull it down to pop it loose – I would suggest getting a plastic trim tool kit from Amazon to make your life easier, and removing the rear pillar covers first to have more room to work once you pull the headliner down.

Cabin air intake

If you notice the passenger floorboard getting wet and it is not from the sunroof components leaking, or a clogged A/C drain line, water is probably coming in through the cabin air intake. When rain hits the roof and windshield, it runs over the windshield wiper cowling, past a water deflector covering the cabin’s fresh air intake vent, down to a channel below the wiper cowling, then out the sides. There are 3 things I did to fix this leak - you will first need to remove the windshield wipers (the nut securing each wiper is under the circular rubber cap at the base of the arm) along with the wiper cowling to access to this area. The water deflector will need to be removed next, it is held on with 2 nuts and some sealant. Note: you can easily check your cabin air filter to see if it is wet after it has rained, gone through a car wash, or had a hose spraying water in the area for troubleshooting.

1. The drain channel can become partially clogged with debris over time, especially if you park under trees, causing water to collect faster than it drains, and cleaning this area out can help. Test how well it drains by pouring water in and see if it backs up. I drilled an additional drain hole, and created a line of silicone that guides some water towards it, which seemed to work ok.
2. The junction between the firewall and cabin air inlet housing has a seal that seems to degrade over time, letting water leak through. Apply a layer of silicone where the cabin air inlet housing meets the firewall. It’s a slightly tight area with a limited visual, so this is easiest if you put the silicone on your finger first, and then apply where it needs to go. It should be easy to feel with your finger beforehand to know where you’re applying it.
3. The sealant between the water deflector and firewall is sometimes inadequate, causing water to run into the cabin air inlet. Once you have the deflector removed, scrape the sealant off both the deflector and firewall. When reinstalling the deflector, apply more silicone to the backside of the deflector. Once installed, you can create a line of silicone to guide some water away from the edges of the deflector and cabin air intake.

Rear windows

If you notice water in the area of your rear windows, interior panels, speakers, seats or carpet, the rear windows may be the culprit and need to be resealed. Remove the interior panels to access the rear glass, remove the hardware securing the window in place, and gently remove it - the window will be held in place with sealant from the factory, be careful when doing this. Clean the factory sealant off, apply silicone, and reinstall. This one is pretty simple.

These are not all of that places that can or will leak in the Genesis Coupes, but these things cause probably 99% of the water leaks into the vehicle.

Thank you for this. Should be pinned to the group.

Thank you thank you thank you!!!

Oh shit .. solid write up .. solid photos

Up

Thanks for this. 👍👍👍👍👍

Damn, you've had to deal with it all lmao

I have random water leaking in and soaking my seatbelt on my driver side (bk1 with sunroof) ... Think this is sunroof related or something else? I have no water staining on headliner. And it is very intermittent.

Tail light gaskets can be enhanced by making them water proof/resistant/repellent. I just sprayed mine with Turtle Wax Hybrid Solutions Ceramic Spray (TWHSCS). Could probably use some other Ceramic coating product as well, the TWHSCS was just already on hand and its cheap, lasts a while on the exterior paint (6-9 months, think it mostly breaks down due to sun exposure). Only really need to coat the top part or where you think the water will flow around it.

this is super helpful! i thought i fixed my leak issues before they began by getting aftermarket lights right away but 2yrs later i started feeling wetness in my back driverside seat & still till this day. im gonna try out that link 👏🏽

I’m buying a 2011 gen coupe this Sunday. I hope to god these problems have already been remedied. Thanks for this guide, I’ll keep my eyes peeled for these issues

So I have water coming in through the rear driver side over my speaker like those last few photos, im not a mechanic and tried to take it to my familys trusted one and he couldnt figure out where the drain pipes were. Really dont want to take it to hyundai for a $250 diagnostic when I know the issue and fixes but dont know how to go about it, or how to access what maky be causing this water to get in through the headliner and little plastic around window