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Removing silica bag from coolant header tank

BigJimNoFool

Active Member
Aug 21, 2021
8
9
Just a wee thread about how easy this is to do. Since my wife's Audi A3 bag burst blocking up the heater matrix we are now looking a big bill to replace the matrix and everyone i speak says that it's not even a guaranteed fix since the silica already in there is difficult to get rid of and will still cause issues. What a s*^t design!

With this in mind i opened up my Leon's header tank armed with a pair of long nosed pliers and some nimble fingers to actually get the bag past the two brackets it sits behind in the tank itself. Once it was past these and into the main reservoir i turned it long ways and pulled it up and out no problem. You can use a little bit of force the bag is actually very solid which did puzzle me as to why they just seem to burst. I supposed some are made on a Friday afternoon on the production line.

I have no issue replacing my coolant every couple of years if this means not worrying about this frankly moronic problem.
 
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rob280

Active Member
Oct 27, 2019
135
53
Hi mate. Also done the same. Once its out of the clips it is easy to get the bag out.

What coolant type do you have to put in once the bag has been removed?
Im guessing it's not the same.

Sent from my SM-A405FN using Tapatalk
 

BigJase88

Jase
Apr 20, 2008
3,767
1,076
I had mine burst in my Audi A3

Took multiple attempts with new matrix. Think the system got flushed multiple times.

Was back at garage 3 times over until it was fully rectified
 

RUM4MO

Active Member
Jun 4, 2008
7,963
1,059
South Scotland
Hi mate. Also done the same. Once its out of the clips it is easy to get the bag out.

What coolant type do you have to put in once the bag has been removed?
Im guessing it's not the same.

Sent from my SM-A405FN using Tapatalk
I'd just stick with VW Group and use their G12evo - it is only coolant that should be on sale at any/all VW Group dealership's parts department. I changed the coolant on my old B8 S4 late last year and so changed it from G12+ to G12evo, my wife's 2015 VW Polo will have G13 in it without any Silicate pouch, but as still have quite a few bottles of G12evo left, I'll probably give it a coolant change early next year to G12evo, I can't think of any good reasons to stick with G13 or any aftermarket G13. So far as I know, there is no one supplying aftermarket G12evo into UK, only in mainland Europe, but as time goes on I suppose demand will increase and so aftermarket suppliers will get their product on sale.

BTW, the manufacturer of G12evo for Europe will be BASF and it is called Glysantin G65, it seems that VW Group only sell it premixed with distilled water 50/50 and is sold as VW Group G12E O5OA2 also, I'd suggest buying it only from VW Group outlets unless you want to spend much more buying it via ebay.
 
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Speedbird

Active Member
Aug 10, 2018
268
135
When I had my Leon Mk3, I had the bag removed by the garage that did the first service.

Now I've got an Ateca, I removed it myself as soon as I got the car. They are such a ridiculous idea. Personally, I wouldn't use any tools, long nose pliers etc, in case you split the bag. I managed to manipulate mine out with just my fingers (even though you see tools, I didn't use them :D)

20220807_095818.jpg
 

Wilto

Active Member
Mar 5, 2021
128
60
58
South Wales
Excuse my ignorance, what's this silica bag for?
What cars are the fitted to?

Just done some googling, going to check my 2018 Leon FR in the morning, probably will remove mine if it's in there, if I can't get it out, I'll buy a new coolant tank, they're only £15 on eBay for a febi one.
 
Last edited:

BigJimNoFool

Active Member
Aug 21, 2021
8
9
Excuse my ignorance, what's this silica bag for?
What cars are the fitted to?

Just done some googling, going to check my 2018 Leon FR in the morning, probably will remove mine if it's in there, if I can't get it out, I'll buy a new coolant tank, they're only £15 on eBay for a febi one.
Supposed to extend the life of your coolant and protect certain engine parts by slowly releasing the silica into the coolant over time. Major design flaw is that they can burst at random or if like my wife's Audi the water pump fails and you lose most of ur coolant.

Most recent VAG cars have them and i believe some others too but im not entirely sure which manufacturers.
 
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SRGTD

Active Member
May 26, 2014
2,551
1,396
Supposed to extend the life of your coolant and protect certain engine parts by slowly releasing the silica into the coolant over time. Major design flaw is that they can burst at random or if like my wife's Audi the water pump fails and you lose most of ur coolant.

Most recent VAG cars have them and i believe some others too but im not entirely sure which manufacturers.
I think Mercedes use them - or they certainly used to.

With VW, if a car has one of those silica bags, ’Mit Silikat’ (with silicate) is printed on the outside of the cooling system expansion tank - like in the picture below;

635A3F6E-0000-4CD7-9F21-AA28ACD70EE2.jpeg


The expansion tank in my 2020 VW Polo GTI+ doesn’t have this printed on it.

Some of the expansion tanks in VW’s are double walled and the bag is in the cavity between the two walls making it impossible to remove it, so replacement of the expansion tank would be necessary if an owner wanted to remove the bag.
 

H Rafiq

Active Member
Jan 5, 2022
1,102
444
If removing the bag, how often should the coolant be changed? Does anyone know if a 2015 Leon Cupra 280 would have a silica bag?
 

BigJimNoFool

Active Member
Aug 21, 2021
8
9
Will the coolant need changing when the bag is removed, or remove the bag then change the coolant after 5 years?
I removed my bag without draining the coolant so i will just keep an eye on it and top us a necessary and then change it when the time comes
 

BillyCool

Active Member
Jan 16, 2020
694
273
Leicestershire, UK
Just a wee thread about how easy this is to do. Since my wife's Audi A3 bag burst blocking up the heater matrix we are now looking a big bill to replace the matrix and everyone i speak says that it's not even a guaranteed fix since the silica already in there is difficult to get rid of and will still cause issues. What a s*^t design!

With this in mind i opened up my Leon's header tank armed with a pair of long nosed pliers and some nimble fingers to actually get the bag past the two brackets it sits behind in the tank itself. Once it was past these and into the main reservoir i turned it long ways and pulled it up and out no problem. You can use a little bit of force the bag is actually very solid which did puzzle me as to why they just seem to burst. I supposed some are made on a Friday afternoon on the production line.

I have no issue replacing my coolant every couple of years if this means not worrying about this frankly moronic problem.

What have you been quoted? A lot of people buy a matrix for €90 and do it themselves. Can take a couple of hours.

Ideally, you do want to dump and change as much coolant as you can.
 

BigJimNoFool

Active Member
Aug 21, 2021
8
9
What have you been quoted? A lot of people buy a matrix for €90 and do it themselves. Can take a couple of hours.

Ideally, you do want to dump and change as much coolant as you can.
tbh mate i'd rather just take the hit rather than f about myself with it since by all accounts its an ahole of a job. local specialist doing in for £500 all in which considering the dealer was gonna be £1300 that's not bad but what's sickening is that it may not fix it in the long term
 

BillyCool

Active Member
Jan 16, 2020
694
273
Leicestershire, UK
tbh mate i'd rather just take the hit rather than f about myself with it since by all accounts its an ahole of a job. local specialist doing in for £500 all in which considering the dealer was gonna be £1300 that's not bad but what's sickening is that it may not fix it in the long term
Fair enough. £500 is better than the stealers. I did my own and it's been 2 and a half years with no issues. I'll just get the coolant changed every 4 or 5 years.

Hope you get it sorted.
 
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LeylandVCDS

Active Member
Apr 20, 2015
392
230
Leyland, Lancashire
A few questions about how often the coolant should be changed if the bag is removed - answer to that is that the coolant is changed at every cambelt change anyway, so no issues at all.
Removing the bag was the first job I did on my Leon 1.6TDI
 
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BigJase88

Jase
Apr 20, 2008
3,767
1,076
tbh mate i'd rather just take the hit rather than f about myself with it since by all accounts its an ahole of a job. local specialist doing in for £500 all in which considering the dealer was gonna be £1300 that's not bad but what's sickening is that it may not fix it in the long term
I got a new matrix in mine. Was good for a couple of weeks and clogged again.

Dealer had to flush it a further 2 times 🤣 it's a proper nightmare