The sunroof is becoming an increasingly popular option on many modern cars. Whether small panels over the driver's seat, or multi-paneled sunroofs that provide fresh air and light to rear seat occupants, the addition can be a part of just about any type of vehicle. However, sunroofs do sometimes leak. Knowing what symptoms to watch for can ensure you get your sunroof repaired before the damage becomes too severe.
One of the most common symptoms of a leaking sunroof is an increase in the amount of wind or road noise entering the car. This can be the first symptom, as it doesn't take much of a gap for wind to enter the car at high speeds and create a whistling or pulsating effect. In some cases, the sunroof or its housing may simply need to be tightened. Other times the sunroof may require a deflector which is a strip of molded plastic that directs wind away from the opening.
Another common symptom of a leaky sunroof is fogging, which can occur on the panel or on other glass, plastic, or metal surfaces inside the car. The fogging is caused by moisture entering the car through the leaks, often overnight as temperatures drop. Fogging can be especially common in humid weather, but should generally not occur inside the vehicle unless there is a leak somewhere.
When a sunroof leak is substantial, water may be able to enter the car. In these cases there will often be no mistaking the source of the leak, as water will pool up directly below the sunroof. The ceiling upholstery may even appear wet or discolored. This can especially happen during a car wash, when high-pressure water is applied to the vehicle roof, or when driving in rain or snow. Leaks large enough to admit water should be sealed or repaired soon after detection, and before other problems occur.
A symptom of a prolonged sunroof leak is often rust. This can occur on the chrome (or chromed plastic) trim around the sunroof, either on the inside or outside of the vehicle. Rust can also spread to the metal roof panels, often requiring extensive repair. If you can see the rust, you can repair it. Try sanding the spots away, re-coating the affected area with a waterproof sealant, and fixing the initial leak.
The most severe symptom of a serious leak is a sunroof that does not operate at all. The relay, wiring, and motors that control its motion are all susceptible to damage from moisture, and may interfere with other electronic systems in the car, such as dashboard instruments. A sunroof that experiences this sort of damage has usually shown one or more of the other symptoms first, which is why prompt repair of any leak is the best choice.