How to Clear a Clogged Sunroof Drain in 15 Minutes

The Mystery of the Wet Car Carpet

If you have recently noticed a musty smell in your vehicle, damp spots on your headliner, or a puddle of water pooling on your front floorboards after a heavy rain, your car has a leak. While many drivers assume a leaking door seal or windshield is to blame, the actual culprit is almost always a clogged sunroof drain.

Sunroofs are not designed to be completely airtight or waterproof. Instead, car manufacturers install a metal tray around the sunroof opening with small drain holes in the corners. These holes connect to flexible rubber tubes that run down through your car's pillars and exit safely underneath the vehicle. When leaves, dirt, and pine needles accumulate in the sunroof track, they wash into these holes and clog the tubes, causing water to back up and overflow into your cabin. Fortunately, you can clear these drains yourself in about 15 minutes using a cheap piece of plastic line.

What You Will Need

• Weed whacker line (trimmer line): About 6 to 8 feet of flexible plastic line (0.080-inch thickness works best).
• A cup of water: For testing the drain.
• A clean rag or microfiber cloth: To clean the sunroof track.
• A flashlight: To help you spot the tiny drain holes.

Step 1: Open the Sunroof and Clean the Track

Park your car on a level surface. Open your sunroof completely. Stand on the door sill so you can look down at the sunroof assembly from above. Use your flashlight to inspect the track and the surrounding channel. Use a damp microfiber cloth to wipe away any visible dirt, leaves, or muck from the channel. Cleaning this area first prevents any loose debris from washing right back into the drains once you are finished.

Step 2: Locate and Test the Drain Holes

Look closely at the front two corners of the sunroof trough. You will see a small hole (roughly the diameter of a pencil) in each corner. To determine which side is clogged, slowly pour a small cup of water directly into the trough near the drain hole. If the water immediately pools and stays there, or drains agonizingly slowly, that drain tube is clogged. If it is working properly, the water should drain instantly and puddle on the ground behind your front tire.

Step 3: Snake the Drain with Trimmer Line

Crucial Warning: Do not use a metal wire coat hanger or a stiff wire brush to clear the clog. The metal can easily puncture the soft rubber drain tubes or pull them completely off their fittings inside your car's dashboard, turning a simple clog into a major, expensive repair.

Instead, take your flexible plastic weed whacker line and gently feed it into the clogged drain hole. Slowly push the line down into the tube. As you push, twist the line slightly to help it navigate the curves of the pillar. Keep feeding the line down until you have inserted about 5 to 6 feet of it. You will likely feel a soft resistance when you hit the clog; gently push and wiggle the line to break through the buildup of dirt and organic matter.

Step 4: Flush and Verify the Flow

Slowly pull the trimmer line back out of the drain. Take your cup of water and pour another small amount into the sunroof trough. Look underneath your car, just behind the front wheel well. You should see water freely dripping or flowing out onto the pavement. If the water drains quickly from the top and exits at the bottom, your drain is successfully cleared!

Step 5: Address the Rear Drains (If Necessary)

Most vehicles also have two rear sunroof drains that exit behind the rear wheels. Because of the slope of the roof, these are harder to see and access from the top. If you suspect a rear drain is clogged (indicated by wet carpet in the backseat area), you can usually locate the exit drain outlets underneath the rear bumper. Look for small rubber tubes or flap-valves. You can gently feed your trimmer line upward from the bottom of these exit tubes to clear out any dirt or debris that has settled at the exit point.