Causes of water leaks in the car when it rains

One of the most annoying problems a car can have is water leaks when it rains or when you are washing your car. Leaks can be in the form of barely noticeable water spots or they can be even more important and can cause quite a lot of trouble for your car.

The consequence of water leaks in the car is the smell of dampness and fogging windows, but also the material in the cabin, usually, the material under the mat that can rotten. The main issue here is that sometimes it is difficult to find the place of the leak. Moreover, they are usually hard to reach.

What are the places where water can leak into the car?

Most cars have obvious weaknesses that can be prone to leaks. Often, water in the cabin after a rain appears in one of them, or even in several at once. But also there are other places that can be formed in time if you are not careful or because of the wear and tear of materials.

Sunroof

The most common cause why water gets into the cabin after a rain. The sunroof frame has drainage holes in the corners through which water that gets here will drain to the ground through hoses that are installed in the car’s roof.

These drain holes can get clogged with dirt and debris. Because it has nowhere to go, water will leak into the cabin. This can happen either at the top, where the sunblind is attached, or at the bottom, in the car pillars, and under the glove compartment.

Windshield seals

If the car does not have a sunroof or it hasn’t got any problems with water leaks, then the next common cause why water can leak into the car is through damaged or worn windshield seals.

It can also be the cause of the windshield that has had a poor replacement, or was installed incorrectly right from the factory, although less common.

Cabin Filter

On some cars, cabin filters are installed directly in the dashboard area under the windshield. If the car cabin covers and seals are not properly positioned or they are damaged or worn, water can enter the air duct and then into the car interior.

Doors and windows seals

When it rains, water gets into the cabin by seeping through the seals on the windows and doors. These either dry out over time or are not installed properly from the beginning and allow moisture to enter the interior.

Door drainage holes

Water that enters the door through the window seal will drain to the road through drainage holes. The problem is that these holes can also get clogged, causing water to get into the interior. You can check the underside of your car doors and see if the drain holes are clogged and try to clean them.

This is also true for the drainage holes of the body that are clogged. They are individual for each car.

Windshield drainage

The windshield drainage located in the engine compartment can also get clogged. Usually, leaves and other large elements can get there at the top, and at the bottom, the holes get clogged with dirt and debris.

If this happens, the moisture has nowhere to go but in the car interior. That is why it is always best to check it from time to time and clean it reguarily

Heater radiator

A similar problem can occur with the heating system. The heater radiator can leak and the coolant will flow into the cat. Detecting this leak is easier by the characteristic of the sweet smell of antifreeze. On older cars, the heater radiator valve also leaks.

Air conditioning drainage

The AC evaporator, which is usually just behind the dashboard on the passenger side, has drainage. It allows water to drain out while driving. If the evaporator drainage gets clogged with debris, condensation will have nowhere to go, and it will start flowing into the car’s interior

If you see water on the passenger’s side it can be from the evaporator. Sometimes the drain hose changes its position and water flows inside the car instead of outside, so the hose must be checked and secured.

Anti-corrosion hole plugs

There are specific cars that have special holes under the car used especially for anti-corrosion treatment and body painting. These holes were there ever since the car was in the factory and they are covered with plugs.

But in time, those plugs can change position, and in rainy weather, or when you hit a puddle, water can get inside the car through these holes, it will accumulate and can leak into the interior.

Trunk drain holes

There are usually one or two drain holes, located in the spare tire storage compartment. If they get clogged, you’re assured of a wet trunk.

Hood cable plug

The place where the hood cable passes from the car cabin to the engine compartment is closed with a rubber plug. If the rubber is damaged or worn out, water may enter the interior.

Body corrosion

A rare situation represents body corrosion when rust forms holes that allow the water to get into the car. Often these tiny holes are present on older car models.

How do you eliminate the causes of water leaks inside the car?

Often these are caused by rubber seals that are wrongly installed or worn. The best option is to replace them. You could also use a sealant like the ones below to treat the windshield seal.

C.R. Laurence CRL7708 CRL Windshield and Body Sealant
Non-Curing Flow Grade Butyl in Cartridge; Remains Tacky Throughout Life - Does not Skin Over
Permatex 81730 Flowable Silicone Windshield and Glass Sealer, 1.5 oz.
Forms a tough, waterproof, durable, clear seal; Resistant to weather, extreme temperatures, vibration, shock and most shop chemicals

Drainage holes and water channels are cleaned manually or by blowing with compressed air. In the case of damaged components, such as the heater radiator, a replacement will also be required.

How to deal with the water inside the car?

For this you will have to use cloth and paper towels because they absorb the water better. You should not neglect the area between the seats, center console and armrests. The best way to do this is to completely disassemble the interior to unsure that everything is dried.

Multiple heat fans will come in handy for speeding up things and it is better to use something stronger than a hair drier. Blow the warm air across the car floor and seats from one side to the other.

Keep the car doors open and leave the heat fans on for extended periods of time. If they have protection from overheating, you can leave them for longer periods of time. This should remove any remaining moisture completely.

Conclusion

Water in the car is not a good thing. Even if the cause is somehow hard to find, it is better to resolve this problem as soon as possible. But the thing is that leaks often go unnoticed for years, and that’s when the damage becomes irreversible. 

Water can cause serious damage to your vehicle and can cause the appearance of mold, which is bad for the driver’s health. Wiring faults and electrical system failures are a common consequence as well. The carpet on the floor will rot apart from the unpleasant smell, which is also harmful to health.

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