Hi guys,
After reading this thread I decided to check the expansion tank on my 2016 Mk7 GTI PP and sure enough I've the Mit Silikat revision G installed so I've fished out the bag with my finger.
It's not the easiest thing to do but definitely doable and once the bag was out I confirmed that it has ruptured and losing crystals. Thankfully it looks like I caught it in time as the bag looks fairly full.
One thing I noticed is that there seems to be at least 3 varieties out in the wild: the straight seal like mine, the wavy seal and the x pattern seal. Not sure if one is stronger than the other.
Having called the dealer and requested a new tank with revision T and G13 flush I was told that unless they inspect the car for €140 they will not be changing the tank!
I declined and asked for the flush alone and was then presented with 2 options, a standard or 'advanced' flush. The latter takes 4h of labour so I went with the standard one, whatever that means for around €150. Hopefully this should get rid of the crystals that managed to seep through before I took the bag out.
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