Water leak in the tailgate [solved]

The summer time that makes us all a bit more lazy. Having more free time I wanted to retrofit something but on the other hand it was difficult to fight my summer laziness. So I ended up getting myself involved in something more easy:

Approximately 2 years ago, I started to notice drops of water entering my tailgate because of heavy rainfall (or when washing the car with my Karcher K4). You could see my earlier post here.

When I first visited the dealership, they had no idea why this leak appeared. Next year I took the car again as the water was more than before. I convinced them to throw water to my car with water hose. Guess what…No water entered the tailgate! I was so pissed by that! It is very diappointing to have a problem and when visiting the dealership to see the problem disappear. It made me seem like a crazy guy to their eyes.

I started looking for similar issues on the internet. What best describes my issue can be seen here (on a Golf 6):

and here (on a Golf 7):

Many people have similar issues but…there was not a single solution for all and each person had a different source of the problem

Here the problem lies with the draining tube at the rear badge
Here also the draining tube is the culprit
Here the culprit was the rubber plug at the lower edge of the tailgate
Here the dealership drilled holes at the rear light to avoid condensation
Here a small hole behind the rear light was the reason for water ingress
Here one person says that the hinges of the tailgate were the problem while another person still is looking for a solution
Almost 10 months ago, here in this forum, I found someone B0tsmAN who had the same problem (his problem was more severe though) due to the dried sealant of the third brake light.

This summer I decided to give some of my free time to locate the source of the leak. One afternoon I covered with a strong black adhesive tape the rear badge, the third brake light and the tail lights and started to experiment with a water hose. I was pouring a lot of water to each part seperately.

The rear badge was eliminated as the source. The tail lights also were not the problem. My rubber plug at the lower edge of the tailgate was dry. The hinges of the tailgate were also absolutely dry. Finally I removed the adhesive tape from the third brake light and poured water. Voila! Water started leaking again! B0tsmAN and me had the same problem

Ordering te spare part
Now I had to buy a third brake light. Two options were in front of me: the original 5K0945087B or the chinese most beautiful 5GG945087C. As it was summer I could wait for the chinese cheaper option 5GG945087C for almost a month without more water leaks. The price was 30€. The seller I used can be found in this link but there is also a slightly cheaper option here

Installation
So the item arrived and I proceeded to installation.

Removal of the old brake light was very easy

Slight differences exist between the two items:

With some pressure I managed to put the brake light back into place.

My impression was that it fits very tight and after washing the car with Karcher my impression proved to be true. No water leaked in the trunk anymore! My happiness was big: clear car without leaks. The new light is of very good quality and seems to be a bit brighter than the factory one

Problem again
Of course you know that life is full of surprises…The next morning I went to the supermarket and left the car at the parking lot under the sun with 35 degrees Celsius. When I returned I saw a familar picture:

I had solved this water streak issue in the past by doing 2 things: first going to the dealership for TPI 2031168/4 and second, by replacing the 5K0955933 water sprayer with the improved version 5G0955933. Now the issue was back…
I thought that probably the chinese water sprayer was the old 5K0955933 version. To check my assumption I had to remove the brake light again. I was not very optimistic about the removal since the new light is very tightly put in place. There was no other way though: I had to replace the sprayer.

So I tried to remove the newly installed brake light but it was almost impossible…I tried and tried and finally managed to…brake some small parts

So…again ordered from China…When the second order arrived I removed the original 5G0955933 water sprayer from the factory brake light and installed it to the second chinese light. Visually the 5G0955933 and the chinese sprayer of the 5GG945087C light are the same. Most probably the sprayer of the first chinese order was defective.

I finally have the combination of a chinese brake light (5GG945087C) with the original water sprayer (5G0955933) that I had bought from the dealership. During the last two weeks it rained heavily once while the other days were very hot. Thankfully everything works as it should: no water inside the tailgate and no water marks on the rear glass. It took me 2 months but I am happy to have solved an issue!

Of course I believe that in a car made in 2013 we should not discuss about water leaks. Of course the factory should have placed better sealant to the factory brake light. My sealant died after 2-3 years which is unacceptable to me.