Golf 7.5 Climatronic. Defrost flap noise. Fresh air vs Hot air.
Tests / observations / investigations.
Endoscope.
Video of the front air distribution flap working, taken with the endoscope.
https://www.youtube.com/embed/dDPZxhga- ... autoplay=1
The endoscope does not have a microphone and the images do not have good resolution because the endoscope only offers good resolution near the object to be inspected. However this video was very helpful because when the light green rubber surrounding the front air distribution flap sits in place, it makes exactly the same noise as the defrost air flap, although in this case it is only when the front air distribution flap sits, not all rotation.
I do not put the endoscope through the windshield defrosting holes, there is a high probability that it will get stuck due to the moderate rigidity of the camera wire... and that doesn't suit me.
![Laughing :lol:](./images/smilies/icon_lol.gif)
Instead, I record the weird sound while I touch the defrost air flap buttons and other buttons in the following video.
https://www.youtube.com/embed/S4hYeKMqw ... autoplay=1
The noise is not so loud in real life, the camera's microphone slightly amplifies this sound, and as seen in the video, with the hot air (HI) the noise is mitigated.
Due to these observations, I conclude that the noise comes from the light green rubber that surrounds the defrost air flap and which in turn is present in the axis of rotation of the flap. Red circles in the following image.
These are my first findings, but until the flap control motors V426 and V107 are removed I will not be able to say exactly the cause of the noise.
The idea to try to fix this noise will be to use pure Vaseline wherever it is possible to reach... (I will have to study the possible ointments).
I will report what is new as I remove parts, there are many, it will take me some time.
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Edit..
- The air conditioning/climatronic system in our Golf has always worked correctly, there are no faults detected in the diagnosis (see last Autoscan posted on this page).
- I have always used the highest quality active carbon air filters with the high filtration capacity for the air conditioning systems of my cars, renewed at each Service/Inspection (earlier than recommended).
- Before starting removing parts, I am going to do a few sessions with the hot air (HI) selecting the position of the defrosting air flap to try to get the light green rubber on defrost flap to acquire another 'structure, texture, consistency', ...and see if this way miraculously it stops making the noise...
![Image](https://i.imgur.com/FlE45dI.jpeg)