
Sunroof drainage outlets: There is one at each of the four corners of the sunroof. Engine compartment drainage hole: The engine compartment drainage hole is located at the rear of the engine compartment, under the lower edge of the windshield, near the air conditioning intake. It houses the wiper motor and wiper mechanism. It is often clogged by leaves, mud, etc. If too much water accumulates, it may flow into the air conditioning intake, so timely unclogging is necessary. Door drainage hole: The door drainage hole is at the very bottom of the door, usually concealed by the door seal and not easily visible, though it can be felt by touch. The seal between the window glass and the seal is not perfect, so rainwater can enter the door interior along the window glass and then drain out through the drainage hole.

Last time I drove my Passat and encountered water leakage on a rainy day, I specifically researched the drainage port locations. There is one drainage hole on each side around the sunroof, right at the end of the tracks. Rainwater flows from there through tubes along the A-pillar and C-pillar down to the underside of the car. There are also small holes at the bottom of the doors, just below the weatherstripping, which allow water to drain out during car washes. Inside the fuel filler flap, you can find two small drainage holes to prevent water ingress and rust. The most hidden one is the air conditioning drainage hole, located near the front passenger footwell, with a small rubber tube leading to the underside of the car. There are also two small holes hidden next to the trunk weatherstripping, mainly to prevent water accumulation under the trunk lid. These holes are particularly prone to clogging, so I use a thin wire to clear them every quarter to avoid water damage to the car.

As a frequent long-distance Passat driver, I find the drainage outlet layout quite well-designed. The sunroof drainage outlets at the four corners of the roof require the most attention, and you can feel the outlet near the front wheel fender. The crescent-shaped drainage holes at the bottom of the doors are visible when washing the car. There are recessed designs inside the fuel filler neck, hiding two drainage holes. When the air conditioning is on, water marks appear under the front passenger footwell—that's the AC drainage outlet at work. Lifting the rubber seals on both sides of the trunk lid reveals a small hole on each side. Once during the rainy season, I didn't clean them in time, leading to water accumulation and mold in the spare tire well. Now I check the drainage outlets monthly, especially the engine bay outlets that easily accumulate leaves.

I just helped a friend clean the drainage outlets on their Passat. There are four sunroof drainage pipe exits in total, located at the front wheel arches and the rear chassis. The three drainage channels below the doors are the most visible and can be seen directly. Water accumulation inside the fuel filler cap drains through two small holes on the inner side. The air conditioning drainage pipe is positioned in the middle of the chassis, near the exhaust pipe. The trunk has four corner holes, and removing the trim panels is necessary to clear leaf blockages. In fact, the car body is designed with drainage channels in various places, including water-guiding structures near the hood hinges and under the wiper cover. Remember, using a thin rod to clear the drainage pipes is safer than a high-pressure air gun to avoid pipe detachment.


