As promised, I did the water drainage hose replacement today and will be sharing some of the things that I've found out:
(1) According to ETKA, 5Q2820127E is the latest revision hence I ordered this part number from e-acca. The part I received is made in china and has a "valeo" logo on it. while the one that came with my car has a "denso" logo, made in Germany but doesn't have an official part number on it. Length and angle wise, they're identical. The section that connects to the evaporator outlet is the same but there's a major difference in the tube outlet that goes out of the car.
The 3 clips are replaced with a round rubber plug that has an attached "slide" for water to drip down - the revised version seems better? What do you think?
(2) Here's a simplified removal steps for a RHD mk7 GT
(3) The outlet hole is covered by the firewall underneath the car, it is impossible to look for the hole underneath the car as there's no direct line of sight.
One good thing about it is the outlet will be protected from any dirt/debris from underneath as the firewall is blocking it.
View attachment 229369
I've inserted a thin tubing into the outlet to check where does it exit.
Based on what I've observed, injecting any evaporator cleaning foam/chemicals from underneath the car without removing anything seems pretty impossible.
You'll have to remove the tube from the body of the car to do so. Or remove the firewall underneath to access the tube outlet.
That's all for now. Feel free to drop me any question regarding this and I'll try my best to answer.