Sunroofs and moonroofs rely on drains to keep your interior dry. Here’s how to clean or clear those important drains.
A common problem with an unexpected cause is water or dampness on the front floors of a vehicle. While there are many ways water can enter a vehicle and end up in the footwells on your carpets, one that is often checked for last is a clogged sunroof drain. Although they seem waterproof, sunroofs and moonroofs really aren’t. They use a rubber seal around the edges to keep most of the water out when they are closed, but under the glass or metal cover around the edge is a drainage system. Generally, the water is routed to the front of the sunroof’s under portion. From there, a drain runs down the A-Pillar. Many vehicles have drains in the front, sides, and or the rear.
The drain follows the pillar down into the passenger compartment on many vehicles and then further down to eventually exit out under the car just behind where the front tire wheel wells are. Some owners manuals show the location of the drains and encourage you to clean them out once in a while. There are other drains exiting under your doors and in the rear section of your car too. Cleaning them out is one of the 6 Ways To Prevent Rust.
Up top, you can clean out the gutters and drains of the sunroof or moonroof assembly with a shop vac. Leaves and other junk find their way into that area somehow and tend to stick around and get soggy, creating a sort of compost that can cause you trouble if it gets into the drain tube. Better to get it before that happens. While you’re at it, grab a shop rag or moist paper towel and run it along the gutters and oper the surface of that little wind deflector that pops up when you open the sunroof.
A quick pass with a shop vac may not pull out the obstruction if it is down lower in the drain passage. The video above offers two suggestions on how to clear a stubborn clog. We favor the snake method. Use a flexible wire, or better yet, a Weed Wacker line to snake down the drain and push out the obstruction. The pressurized air hose method worries us because it can make a loose clog more compact and more difficult to finally clear out.
Since you already dragged out the vac, pop the trunk and clean out any debris in the truck lip drain. Then, pop the hood and give the cabin air intake grills near the base of the windshield a quick cleaning. The cabin air filter you save may be your own.