How to fix a leaky sunroof

By Chad Lückhoff

It's our excellent weather, blue skies and connection with nature, that makes us gravitate towards open-air motoring. We love sunroofs, and if there's one optional extra that adds value to a used car, it has to be the sunroof.

We like feeling the sun on our heads and the air rushing through the cabin as we drive, but we also like knowing that our car is safe when we leave it parked and like the idea or being able to close it in an instant when it starts to rain – which it does, sometimes without warning.

There's also nothing more infuriating than having a sunroof fail on us, leaking when it rains and drenching not only us but our entire interior with water. The good news is that this doesn't mean having to sell the car and it may not even be as expensive a fix as you think.

Here's how to fix a leaky sunroof:

Step 1 - Clean the rubber seals and trough.

Grab a clean rag or cloth and wet it down, wringing out excess water. Use this cloth to wipe down the rubber seals and to clean out the trough that the water collects in. You may notice that there is a fair amount of grit and grime in this trough which is mainly just dust that has collected and mixed with water. A mild soap detergent or car cleaner will help move some of the stubborn grime.

Step 2 – Locate the drain tubes.

The drain tubes are small openings in the trough that allow water to escape and are usually routed down the A-pillar of the car, next to the windscreen. These can often become clogged up over time with the aforementioned dirt buildup. Check to see that these are not blocked with visible debris then move onto the next step.

Step 3 – Clearing the drain tubes.

The best tool for this is a small length of cable. A bicycle brake cable will work wonders and failing that, a small length of thin cable from the local hardware will do the trick as well. The reason for using the cable and not a piece of wire is that a straight, hard piece of wire may damage the channels and cause even more problems than you already have.

Feed the cable into the drain tube, using slight pressure while rotating the cable. This should clean any debris trapped in the drainage tubes. If you encounter any resistance, back the cable up and try the rotating motion again, applying steady pressure. Repeat for all the drain holes.

Step 4 – Check with water.

Pouring a small amount of water slowly into the trough should see it draining out of the drain holes and not into the interior. The water should steadily drain and not build up or bubble.

Step 5 – Inspect the seal.

Check the rubber seal around the sunroof for signs or perishing and cracking. Any suspicious wavy rubber seals may need to be replaced, and for this, it is best to go to a sunroof installer to see if a replacement is necessary and can be found. Try not to use silicone sealer on any of the seals as this will only lead to further leaking.