This car is a very good example of what happens with sunroofs on many makes and models of cars.
In fact, both the leaks on this Jetta are generic problems which happen to practically call cars because all cars are assembled in much the same way.
Around the sunroof is a trough, where water can collect (this is often called the cassette for some reason), from here there are usually two or four drainage holes with silicone pipes which lead down to the front wheel arches. It is seldom the case that these silicone pipes are in one piece, and often they have a connector. Over time, the silicone pipes shrink and shorten, so they can pull off the connectors, or they can just work their way loose. It is sometimes the case that the connectors are made of plastic which perishes, becomes brittle and shatters, so there are a number of things that can go wrong back there in addition to just blocked pipes.
There are generally two things that can go wrong with the rear air vents, they can get dirty and grit and debris can stop then closing properly, or perhaps more common, the plastic and silicone seals become old, shrink or not as supple. These vents are a bit like a one way cat flap, they are a valve with a gate(s) that let air out, but not water in. Usually just a plastic hinge, time can take its toll on them, which is why its often best just to replace them.
Solution: We will example the sunroof pipes and see if they can be glued back in, if there is a lot of shrinkage, it might be best to buy a new set and replace them, but this is up to the customer to decide.
We will replace the back air vents as this is the sure-fire solution and as the parts are usually available and aren't much money, it's the most cost-effective solution.
It's worth saying that the parts companies will keep fan belts and brake disks in stock because they are often replaced and in high demand. Some of the parts we wish to replace, which are bits of plastic interior trim, brackets, pipes and connectors, are often not kept in stock. They need to be ordered, and you never know what the availability is. It can take days or weeks for parts to arrive, especially if they have to come from abroad. Not always, but it can cause complications.
Water Leak Detection for Volkswagen
Do you think your sunroof is leaking, but you aren't sure? It can be hard to find leaks, but we are experts at it.
Question: "I have repaired my leak, but my car is still damp. How long does it usually take for a car to dry out?"
Answer: Unless you actively dry the car, perhaps never. There may be far more water in your car than you realize, and it can get trapped under plastic lined carpets. Generally the best way to do it is to remove the seats and lift up the carpets. There is more advice in the videos below.