Silica bag removed

vw754

vorsprung Durch Technik
Removed it from my 2015 s3
Do i leave it at that, or do i replace the coolant tank which comes with a new bag?
Don't want cause any issues with not having a bag in the tank, ive heard it is a corrosion inhibitor which stops water pump from corrosion and also helps coolant to last longer?
Anyone removed theirs and not had any problem's, if so how long has it been since removed?
 

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NHN

Retrofitter - Audi - VW - Skoda - Seat
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Search the forum, it's been covered quite a few times.
 

vw754

vorsprung Durch Technik
Search the forum, it's been covered quite a few times.
THANKS nhn.... I have getting mixed answers.... Some say must stay in some say leave out, some say if left out, system will get corrosion..... Confused what to do.... Some say get new header tank with new bag....
 

B5NUT

Well-Known Member
VCDS Map User
There is no right or wrong answer to this. You either remove the bag and then replace the coolant every 2-3 year to replace the silica that is lost over time (not a bad thing as you also flush the **** out of the system) or you replace the tank every few years. The decision is yours!
 

rafletcher

Registered User
There is no right or wrong answer to this. You either remove the bag and then replace the coolant every 2-3 year to replace the silica that is lost over time (not a bad thing as you also flush the **** out of the system) or you replace the tank every few years. The decision is yours!

Ah, that's a good response, now I understand a bit better. When mine goes in I'll talk to the garage about removing it as I don't mind paying for a flush and coolant change every couple of years, along with the brake fluid.
 
I replaced my bottle today with a brand new genuine one £23 so no biggy. With the latest 'M' revised part with no bag. Had to smash my old bottle to get the bag out and it looks new ish. My car is 63 plate with 51k and my old bottle still looked new. Didn't really need to be done in hind sight but peace of mind and all that. I'll top it up with new g13 and replace the whole system every few years
 

vw754

vorsprung Durch Technik
I replaced my bottle today with a brand new genuine one £23 so no biggy. With the latest 'M' revised part with no bag. Had to smash my old bottle to get the bag out and it looks new ish. My car is 63 plate with 51k and my old bottle still looked new. Didn't really need to be done in hind sight but peace of mind and all that. I'll top it up with new g13 and replace the whole system every few years

Did u buy a genuine coolant tank?
I've left mine out, renewing the coolant every 2-3 years is no stress
 
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vw754

vorsprung Durch Technik
Sorry u have said genuine lol.... Did the dealer explain why the new tank hasn't got a bag?
 
I got it from TPS. They didn't know why and state that there is no part number for the bag in the latest build list. So I'm puzzled. Tempted to source a bag and renew it annually????
 

vw754

vorsprung Durch Technik
I got it from TPS. They didn't know why and state that there is no part number for the bag in the latest build list. So I'm puzzled. Tempted to source a bag and renew it annually????
Wouldn't bother to be honest ive read on some forums of bags splitting at 16,000 miles, just renew coolant every 2 years from when you took bag out.
 
Fair point. I just know these are a b£€#tch to bleed but I suppose it's not too bad. How many litres do they take from a full drain?
 

vw754

vorsprung Durch Technik
Fair point. I just know these are a b£€#tch to bleed but I suppose it's not too bad. How many litres do they take from a full drain?
I've no idea had my car for a few days lol.
My mates heating went cold, the bag split and blocked heater matrix took all day remove and clean, flush out... And cost him £500+.
 

Bigjase88

Registered User
My bag burst

New heater matrix and flush a couple of weeks back

afterward the drivers side wasn’t as hot as the passengers.

couple weeks on and i have lost all heat again. I think the new matrix is already blocked with stray bits of silicate.

all under warranty though, but this could happen to anyone still with the bag in place. Get rid of it ASAP
 

vw754

vorsprung Durch Technik
Going off subject here.... My battery was low.... I mean very low...... Been listening to music without car running, so today removed the battery and had it on charge, just put it back in the car, all sorts of faults... Tpms, hill hold unavailable, suspension fault... And few more.... Tried clearing them with vcds... No joy, keep coming back, some saying missing data or something...... Does it need to be driven or something?
 

traindweller

Registered User
Looking at the above posts made me check and to my surprise none of the family cars, (15A3, 19A3 and 17A1) had one, or had the tank identifier. I wonder why some do and some don't, anybody know? The two a3 are both 1.4 COD and the A1 1.4,all from new and no new tanks fitted.
 

Bigjase88

Registered User
Looking at the above posts made me check and to my surprise none of the family cars, (15A3, 19A3 and 17A1) had one, or had the tank identifier. I wonder why some do and some don't, anybody know? The two a3 are both 1.4 COD and the A1 1.4,all from new and no new tanks fitted.
No idea

my mother has a Q3 2013 2.0tdi and no silica bag
My A3 2013 2.0tdi did have a bag
 

NHN

Retrofitter - Audi - VW - Skoda - Seat
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If the part was superseded to an M with no bag or part number for the bag, Audi have come to there senses & realised the issues these cause & removed them from the parts they'd now use to replace a faulty unit, so they clearly don't use the bags anymore.
 

alpesh26

Registered User
I took mine out at the weekend. No need to replace the tank, syphon out the coolant in there, remove the hoses and electrical connector. Take the bag out of the tank and reinstall. Doing it this takes away the risk of it clogging up the coolant system if it bursts when taking it out. Topped up with some new pre-mixed G13 (you will need less than 1 litre). Took 20mins
 

AlS3BE

Registered User
Has anyone figured out why or how they burst? Age? Is it replacement coolant not compatible with the silicon in the bags? Or is it something simple like someone shoving a funnel too far into the coolant tank and bursting it? Some of the ones I hear about seems to coincide with coolant change at 2/3/4 year old cars.
As I said before they are pretty sturdy so in theory shouldn't burst on their own as not much goes on in the coolant tank other than heat/cold and a bit of pressure.
Just playing devils advocate cause don’t want everyone yanking them out and potentially causing other issues.
 

alpesh26

Registered User
Just playing devils advocate cause don’t want everyone yanking them out and potentially causing other issues.

I think it just age because it doesn't seem to be happening on new cars. Maybe they are going brittle? The bag is quite robust but age will eventually get to it as its only thin meshed plastic.

My dad has a 2019 Audi Q2 which uses G13 coolant like my 2017 S3, but the expansion tank in the Q2 doesn't have the silica bag, yet the coolant is the same. There is an argument to say that a 1.5TFSI and 2.0TFSI have different requirements so maybe that's why the bag is there in the S3 but not in the Q2?

I'd rather not have the risk, hassle or cost of it bursting because it extends the life of the coolant when I can change it more frequently and clean the rubbish out of the system too. I personally don't believe in this "sealed for life" business where fluids are involved, with use they eventually break down.
 

CanadaA3wales

Canadian living in South Wales - Audi A3 8V 150BHP
I have played with the silicon bag and the only 3 ways I can see why they burst is:

1. You have let the coolant get too low and this has caused the bag to dry out and possibly crack
2. The heat and cold over and over, also the freezing conditions and heat of the engine ect.
3. People have not used the correct pink coolant which should be G12+ or above.

Or and I dont think would be possible, the bag was damaged from the factory, but your matrix would get damaged soon after purchase.

The bag is very strong and robust, and if it constantly has liquid, I cannot see why they would break as it has its own housing so its not like its sloshing around the tank as you drive.

Also OP has taken a picture of his bag and its a very dirty brown which I cannot understand as the coolant is pink, it looks like some oil has gotten into the resevoir.

My car is a ex lease on very high miles, 119,000 and my bag is still soft and bright pink, not black and dirty, so maybe people are using the wrong coolant, I dont know.

Either way, if you have it, remove the tank, use some pliers and get it out, give it a nice clean and get some more G13 back in, it will take like 20 min and you have peace of mind. Its either that or a possible bill close to £1000.00 for a brand new heater matrix.
 

AlS3BE

Registered User
Maybe that’s the warning sign. If it changes colour get the thing out and change coolant.
I still have my factory warranty so just leaving it there. Don’t want a argument for warranty for corrosion in the pipes/head/block and they blame me for removing the tea bag out the coolant tank.
 

Bigjase88

Registered User
I would just remove it.

i have had VAG cars for years and this is the first one with a silica bag, just change the coolant more often, they should be getting a new timing belt and waterpump every 4 years anyways so there is your coolant change.

my A3 had FULL audi service history and the bag burst, so who knows.

i personally would not run the risk, a 4 figure sum to replace a blocked matrix or just change coolant more often.

i am just fortunate the garage is picking up the cost of repair on mine, i think they might actually have to throw a 2nd heater matrix at it cause i’m pretty sure my 2 week old one is now blocked solid from remnants of silica!
 
I didn't think mine had a bag but it was unaccessible in a sealed chamber (2013 63 plate s3) the later bottles allow access to the bag, if there is a label on the tank (Mit Silicat) then it has a bag, I had to replace with a later bottle.
I got my bag out and the bag looked very good, slight discolouration to one corner (maybe a sign it was starting to deteriorate) but no where near like some I have seen, so seeing my car has 51K and is nearly 7 years old it cant be age or mileage related as some sub 20K cars 2 years old suffered from it.
I have made sure my coolant is strong and never ran low and always warmed up and cooled - maybe it has something to do with it
 

CanadaA3wales

Canadian living in South Wales - Audi A3 8V 150BHP
Well I have finally just taken mine out, I was waiting for some more pink stuff
I tried to take the resevoir off but the metal grip clips were stuck on there good and I couldnt hold the hose and clips at the same time and pull, so I used a butter knife to move the silica bag over and used needle nose pliers to pull it out gentley
As you can see my bag is a bright pink with no disclouring, and my car is on 119k also had the OEM resevoir
This is strange why some are brown with a lot newer cars and a lot less miles.
 

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Well I have finally just taken mine out, I was waiting for some more pink stuff
I tried to take the resevoir off but the metal grip clips were stuck on there good and I couldnt hold the hose and clips at the same time and pull, so I used a butter knife to move the silica bag over and used needle nose pliers to pull it out gentley
As you can see my bag is a bright pink with no disclouring, and my car is on 119k also had the OEM resevoir
This is strange why some are brown with a lot newer cars and a lot less miles.
mine looked the same except one corner was slightly darker
 

AlS3BE

Registered User
Well I have finally just taken mine out, I was waiting for some more pink stuff
I tried to take the resevoir off but the metal grip clips were stuck on there good and I couldnt hold the hose and clips at the same time and pull, so I used a butter knife to move the silica bag over and used needle nose pliers to pull it out gentley
As you can see my bag is a bright pink with no disclouring, and my car is on 119k also had the OEM resevoir
This is strange why some are brown with a lot newer cars and a lot less miles.

I think this proves my point earlier. Ripping it out willy nilly will prevent it it going bad and blocking stuff up but what we need to find out is the root cause of the problem as some have the double wall reservoir and can’t be yanked out so needs new parts and not all is mechanically minded or brave enough to remove parts so this adds extra cost whereas the tea bag is meant to save you problems long run. At 100k+ that looks like mine with 17-18k so it’s done it’s job effectively and lasted well.
With the ones going brown it’s clearly some sort of contamination but what is it that’s contaminating it? I think that’s what we should try and figure out as this contamination could wreak havoc on other stuff as well not just this silica tea bag.
 

CanadaA3wales

Canadian living in South Wales - Audi A3 8V 150BHP
Could be a head gasket as that would cause oil to leak into the system, but then again no one has complained about having to do the gasket.

TBH even if its taken out, I have never had a car with these bags, so they are not esential to the vehicle.

As long as you drain the system every 2 years and keep everything topped up then you cant go wrong.

Or... The bag breaks for no reason and your in for a world of hurt... If your out of warranty.
 

ScottishA4B9

Registered User
So I’m looking at removing my bag ASAP.
Is there a way to drain the current coolant in their to refill with some fresh stuff?
 
I managed to unclip the tank and disconnect the top return pipe. This gave enough flexibility to drain what was in there into a container before taking the man pipe off.
 

Bigjase88

Registered User
So I’m looking at removing my bag ASAP.
Is there a way to drain the current coolant in their to refill with some fresh stuff?
If you want to replace all the coolant in the whole system there is usually a tap at the bottom of the radiator, i assume the A3 8V is the same.
 

CanadaA3wales

Canadian living in South Wales - Audi A3 8V 150BHP
I was going to take the coolant out but I just had a service and it was pretty fresh.
Just a butter knife to move the bag to the hole and grab the bag on the corner ( Do not grab the silica ) as it may puncture.
Slowly move the back back and forth and it will come out, but you do need to have some confidence, just dont pull too hard.

The bag is quite thick so I dont think there is much risk of it breaking unless the bag looks in poor condition.

Butter knife
Needle nose pliers
more coolant

If your bag is brown or discoloured then I would remove the tank first and take it out as it may break inside the tank and it would be a disaster.
 

ScottishA4B9

Registered User
I’ve checked the service history of my car and the coolant was changed last year so should be good?
 

CanadaA3wales

Canadian living in South Wales - Audi A3 8V 150BHP
See those metal tangs in your first picture?
Its pressing near the bag.

As you are at the front of the engine and looking in the tank, its in the far right corner , use a butter knife to manuver it towards the hole
 

CanadaA3wales

Canadian living in South Wales - Audi A3 8V 150BHP
Remember some tanks have a sealed unit/bag, if thats the case you will need a new tank and wont be able to remove it.
 

CanadaA3wales

Canadian living in South Wales - Audi A3 8V 150BHP
Why does it look suspect, mine looked like that and its fine?
Bright pink liquid, but the engine needs a clean LOL
 
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