Hi,

I have just unplugged to check if my Skoda Fabia 2018 1.0 TSI expansion tanks contain silica so as to replace it with silica free and completely change the anticoolant from G13 to G12evo.

The OEM number is 6Q0121407B.

Attached are the photos. I have asked three AI engines but all say is silica free.

I just wanted a second opinion so as to proceed with only anti-coolant change to G12evo.

PS. the level of coolant is low because I sucked out a bit in order to be easier to unplug to check the OEM.

Welcome to the forum.

Usually the OEM EV is marked 'Mit Silicat' if they were fitted with the Silicate bag (or later) plastic dispenser.

It's possible that EV is not original.

If the bag is present, it can usually be seen if a light is shined through the EV wall, especially the double-walled type - the plastic dispenser should be visible by removing the cap and looking at the bottom - I'm not aware of any issues relating to the plastic dispenser type though.

To be certain, why not just replace the EV for a new one when you change the coolant to G12evo?

Edited 10 hours ago10 hr by Warrior193
added information

Thank you for the reply! It is actually the original tank since I bought the car brand new in 2018. There is no tag "Mit Silicat".

Now my Skoda is in 70 000km so was checking to pump out all the G13 from system (had done it when car was 4 year and 35000km).

And in the search I found out that G12evo is replacing G13 but to replace the expansion tank in case is silica double-walled type.

It does not have any silica bag inside, that I have been inspecting carefully.

AI engines says that 6Q0 121 407 / A / B was already used on earlier Fabias, long before the later 5Q0... silicate-reservoir issue,

Since there is no problem with the tank I was thinking to keep it if is silica and replace later on a damage or leak.

Edited 9 hours ago9 hr by AlexNk

I think that what happened was, VW Group or their coolant supplier BASF, became a bit more environmentally aware and so "greened" the coolant and so G12++ became G13, some time after this, VW Group or BASF became aware that for some engine version uses or at least the typical working temperature was causing enough silicate to get depleted to cause concerns. This was addressed by "sort of" providing silicate pouches for some model/engine combinations - so some models/engines were sent out with the "Mit Silicate" reservoirs while at the same production/sales periods, some cars were sent out without these pouches in the reservoirs.

While my wife's 2015 VW Polo 1.2TSI 110PS - factory filled with G13 aged, it was sent out without a silicate pouch in the reservoir, the ph level in the coolant changed quite quickly - compared with my older daughter's 2019 SEAT Leon Cupra - factory filled with G13, which has a "Mit Silikat" reservoir - so these pouches do seem to do what they need to.

I think that VW Group was gaining info about this G13 as time went on, and if they had had enough info on G13 in the 1.2TSI 16V engines, that 2015 VW Polo 1.2TSI 110PS would have been sent out from the factory complete with a "Mit Silikat" reservoir!