9 Causes of Interior Leaks (Water in Car)
Few things can ruin the interior of your car faster than a water leak. Water pooling inside your car can cause a foul odor caused by mold. In extreme cases, mold growth can have adverse health effects.
If you have water leaking inside your cabin, fix the problem right away. Aside from accidentally leaving a window open when it rains, here are some common causes of interior water leaks:
Causes of interior leaks
1) Convertibles
If you drive a soft-top convertible, you know how difficult it is to keep water out of your car. Water often leaks into the cabin over the window or through the seal where the top meets the windshield bracket (top of the A-pillar).
Most convertibles have some adjustment options that allow you to position the fabric top closer to the window or A-pillar. If the top doesn’t fit properly, a simple adjustment may be necessary. Fabric tops with holes may need to be patched or replaced. Each vehicle model has different settings. For example, early Mazda MX-5 Miatas have adjustable soft-top latches and window heights.
2) T-Tops, Removable Hardtops, and Targa Roofs
Like convertible soft tops, T-Tops, removable hard tops, and Targa roofs all have seals around the perimeter of the removable roof. Over time, these seals can break down.
If you’re transferring the roof from one car to another, you may need to adjust the latch tension slightly to keep the roof securely attached to the car. Weatherstrips may also need replacing.
3) Pressure Washing Behind Seals
Pressure washing is a great way to clean your car if used correctly. Using the pressure washer too close to window seals or weatherstrips, or holding the pressure washer in place for too long, can cause water to get inside.
If you accidentally get water inside your car, run the air conditioner for a while. This will dry the air and remove excess moisture before it can cause problems.
4) Sunroof Seals
Sunroofs and sunroofs do the unfortunate job of keeping rain out while being exposed to 100% of the worst weather.
Because sunroofs are installed on the roof of your car, water must drain through rain gutters. If these gutters become clogged, water can accumulate inside your car, especially in the headliner.
There are special tools to unclog sunroof drains, but you may be able to unclog them yourself using a long string trimmer hose and some air from an air compressor.
5) Automatic Car Washes
Automatic car washes are convenient, but they’re not very good for your car. Some non-touch car washes spray water onto your car at very high pressure.
After an automatic car wash, you may notice water getting into the cabin. Once you have verified that none of the windows are cracked, you may want to run the air conditioner for a while to dry out any wet areas.
If you didn’t notice the leak until after you washed your car, it’s probably nothing to worry about and you don’t need to do anything.
6) Air Conditioning Drain
If you leave your air conditioner running, condensation will form on the unit as it cools. This condensation has to be able to drain somewhere. Usually, you’ll notice water pooling under your car when you turn on the air conditioning.
If this drain gets clogged, the condensation may have nowhere to go except inside the car. Finding the drain under your car may help clear the clog. Some vehicles may need to be lifted to allow enough space.
7) Door Seals and Moisture Barriers
Door seals have two purposes: to eliminate noise, vibration, and harshness (NVH) and to keep water out. This rubber coating is very similar to the seals you find on a sunroof, tailgate, or convertible top.
Doors also contain a moisture barrier under the door panel. This plastic film protects the door panel from moisture. The moisture barrier is attached to the door with a black sticky substance that sticks to anything (be careful not to get it in your hair).
Vapor barriers are often dislodged during aftermarket stereo installation, weakening the bond between the barrier and the door. If the vapor barrier is leaking, you should remove the door panel and check to see if the vapor barrier is still in place and installed correctly.
8) Windshield Shape
Windshields must be both airtight and waterproof. Windshields are sealed using a combination of a windshield seal and an adhesive that holds the windshield in place.
If this seal begins to deteriorate, you may see water pooling on the dashboard or condensation around the edges of the windshield. You may also notice a whistling sound when driving at higher speeds, as air flows past the seal.
9) Flying Water Bottle
It may sound silly, but before you spend a lot of time or money looking for the problem, check your car for any liquid containers that may be leaking. While driving, a water bottle can easily spill if it is shaken by bumps in the road.
Conclusion
There are many different causes of water leaks in the cabin, but you can usually identify where it is leaking from. You will usually notice a lot of moisture near the source of the leak. Many of these leaks can usually be fixed at home and are relatively inexpensive to do yourself.