Silica Bag

[Boatman1]

Had to replace the original matrix on my 2014 Octavia 46,000 miles because it was blocked. I read on a VW forum that this was caused by corrosion within the VW cooling system also that this corrosion leached silica out of the coolant hence the silica bag in the filler reservoir to prolong the life of the coolant. I replaced it with a Nissens matrix which apparently has wider veins . Does anyone know whether the silica bag is still required in the coolant reservoir, was it just the matrix that rusts or are other parts of the cooling system prone to rust?

Apparently this is a problem throughout the VW range from 2013-2017 anyone else encountered this problem?

[Stuart-h]

Mines regerstered in 2019 and has the bag in the coolant if that counts. 

[Saints92]

Through my work we've had 4, maybe 5, blocked heater matrixes due to the silicone bag exploding. You have to replace the matrix, header tank, and flush the whole system multiple times to resolve it.

 

Never come across a rusty matrix caused by not having the silicone bag, and honestly I'd be using a header tank without it if I bought a car with one.

 

Thats a really small sample size I've got though.

[octavia5]

On the Golf forums there are multiple posts where the Silica bag has burst resulting in expensive repairs - as it nearly always splits when the warranty has run out. The general consensus is to either remove it (carefully so as not to split it yourself), or buy a header tank without one and change it over, and occasionally top up the header tank with neat additive.

[Gaz]

 

Mine's coming out as soon as the car is out of warranty (VW advised me that removing it while in warranty will void the warranty).

 

Gaz

[FrankLK]

As my water pump leaked after only 50tkm, it was oportunity to go for G12 Evo and of course without silica bag that I removed already in the past.

[NZ100]

I've just had cambelt done, just before I left garage the mechanic said, by the way I removed the silica bag, made sense really. One thing I haven't got to worry about. 🥴

[3rdoctavia]

I had a split silica bag which was replaced as part of the skoda used car warranty that came with the car. Main dealer flushed system etc and replaced the tank ... I didn't ask for it but the one they replaced it with didn't have the silica bag in it.

Cheers