Water Leaking Into a Car

If you have water leaking into your car, you need to deal with it promptly because of the many serious problems it can cause. If water sits for too long in a car's carpet, mold can grow and cause bad smells. Other problems can include corrosion of pin connectors, computer failures, sensor failures, rust, and high humidity inside the car causing your windows to fog up.

A wet carpet is not the only sign of water leaking in a car. If you have an idea of where the water is getting into the car, check for water marks, stains, or even signs of rust. Take a close look at connectors for corrosion and check brackets for rust spots; you will be amazed what you will find when you look for it.

I have always said, "Mechanics' best tools are not found in their toolbox, they are found in their heads." Water leaks are hard to pinpoint, but once you find exactly where the water is coming in, you can access the problem spot and repair it.

Finding the point of entry is the first step in keeping rainwater out of your car. This investigation is time-consuming, but something you can do yourself. You need to physically see where the water is coming into the car, not just where it is traveling along a panel or a seam. To test your car, pour water on it: start at a low point and work your way up to the roof. If you determine that water is leaking into the bottom of the windshield, there is no need to go any higher with the water test until after you've fixed this first low leak.

A foul, moldy smell in the trunk may result from water getting in around the taillights or the trunk lid. If you can identify these leaks you can get them fixed.

Poorly installed aftermarket accessories are another major cause of water leaking in your car. Anything from a sunroof to a roof rack system, if not installed properly with the right sealer, will cause a water leak in a car.

If you have a factory-installed sunroof, check the drains. Sunroofs leak! That's why a factory-installed sunroof has a built-in tray with four drains, one in each corner of the sunroof. Sometimes these drain tubes become disconnected or clogged and will cause water to leak into the car. Locating the drains and checking them for proper drainage can take some time because they are usually buried in fenders and body panels, but it's time well spent. A shortcut to locating the drains is to fill the sunroof tray with water and watch where it goes when it drains. It will usually spill out in the front and the rear of the rocker panels.

Some leaks into the passenger compartment happen when it hasn't even been raining; they involve fluids created by the car's cooling or heating systems.

Clogged Air Conditioner Drain

When air conditioners take humidity out of the air in the passenger compartment, they end up collecting a lot of water that has to drain out of the car. Water dripping out of the air conditioner drain onto the ground is totally normal; water dripping onto the floor of the car from the air conditioner is not. If you haven't had any rain, and you have water leaking onto the passenger's floor, check your air conditioner drain or evaporator drain; it may be clogged or disconnected. Debris gets sucked into the evaporator from outside and occasionally will clog the drain tube. A temporary quick fix for this problem is blowing compressed air into the drain tube located under the car, but eventually you will have to remove the evaporator and clean out the debris.

Leaking Heater Core

Another possible cause of wet carpet, especially in the front of the car, when it hasn't been raining, is a leak from the heater core. Car heaters circulate coolant through the dashboard area to heat the car, and if the heater core springs a leak, coolant can drip onto the floor.