Sunroof leaks when it rains — How to repair

Most sunroof leaks are caused by clogged drains — Here’s how to clean them

It’s impossible to make a sunroof that doesn’t leak. Carmakers learned that the hard way. So, if you can’t stop sunroof leaks, the next best thing is to design a drainage system. That’s what carmakers have done. Every car with a sunroof, also has gutters and drains directly under the sunroof seals so the water can drain out without damaging your vehicle. Sunroofs have at least two drains in the front corners and one or two drains in the rear.

Leaves clog sunroof drains

Leaves and organic matter that gets caught in the tracks will wind up clogging the sunroof drains. When that happens, water will leak into your vehicle.

Locate the sunroof drains and clean them with vacuum, not a coat hanger

DIY’s often try to snake the sunroof drain using a coat hanger.

Sunroof drain from Honda Parts diagram. It’s not all one piece. Don’t risk disconnecting the couplers

DON’T DO THIS! The sunroof drains are made from rubber tubing and a coat hanger will puncture the drain line, causing a worse leak. In addition, many drains are connected to couplers, so even if you get the snake down the tube, you may disconnect the coupler and flood the A-pillar with water. To replace the line you’ll have to drop the headliner and A-pillar trim and run a new drain line.

Here’s the safe way to repair Sunroof leaks — with vacuum

Most of the clogs are located right at the top of the drain tube, so it makes more sensor to VACUUM out the clog than to try and push it all the way down the front or rear pillar. Unfortunately, these drains are small and many times your household vacuum cleaner hose can’t get in deep enough to create the suction you need. So make this simple adapter using PCV parts from any hardware or home center store. Then use your vacuum cleaner to suck the debris out of the drain tubes.

If that doesn’t work, and the clog is farther down the drain, purchase a speedometer cable from any auto parts store. Insert the flexible cable into the tube and twist it as it goes down. That will break up the clog. Then you can suck the debris out with your sunroof drain tool.

Sunroof leak repair tool

To make the vacuum hose adapter you’ll need the following items:

• 1-1/4″ x 1-1/2″ male PVC trap adapter
• 1-1/2″ PVC cap
• 3/8″ MIP (threaded) x barbed adapter
• 3/8 I.D. vinyl hose
• If you plan to use a shop vacuum with a 2-1/2″ hose, purchase a 2-1/2″ x 1-1/4″ reducer.

I used PVC primer and glue to permanently glue the cap to the trap adapter. Then I drilled a hole in the center of the cap and screwed in the 3/8″ barbed adapter. Attach the vinyl hose the barbed end of the adapter. If you’re using a shop vacuum with a 2-1/2″ hose, simply add on a reducer. Insert the vacuum hose into the trap adapter and tighten the nut. Then vacuum out the clog.

Most sunroofs have at least 3 drains; one in each front corner and one in the back

©, 2022 Rick Muscoplat