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Burst silica bag - can't get it solved

VWgolfSC2013

New member
Location
Ireland
Hi,

I'm new to this so I hope I'm doing this right. I have a 2013 Mk7 1.6TDI golf. My heating stopped working about 5 weeks ago and I took the car to a mechanic who found it was a burst silica bag. To fix this, he replaced the heater core and flushed the system thoroughly, until he was sure it was clear. The overflow tank and thermostat were also replaced, to be on the safe side.

Having done this, I took the car back but the heating hasn't been working right since. I've had it back several times and now, having tried everything else, he checked the heater core again. And, once again, there's silica in it. A small amount, nonetheless enough so that the heat is only working on one side of the car.

I'm wondering if this is a problem that anyone has had success fixing. Will the heating in my car ever work correctly, and is it even possible to ensure that all the silica has been removed from the system? I can't see myself holding on to this car for too much longer if this is going to be an ongoing problem.

P.s. why has this problem never been addressed by VW? Clearly, many people have fallen victim to it and yet, there's no recall and no advice to change/remove silica bags, despite this being relatively widespread.

I'm really at my wits end with this, and it's already cost a lot of money, so any help would be appreciated.

Thanks.
 
Last edited:

Storm19999

Passed Driver's Ed
Location
U.K.
Won’t be silica it will be casting sand. Known fault with Vw. You might end up taking to Vw then calling customer services as only 6 years old and sales of good act.
 

golfdave

Autocross Champion
Location
Scotland (U.K.)
Car(s)
Mk7 Golf GT Estate
Won’t be silica it will be casting sand. Known fault with Vw. You might end up taking to Vw then calling customer services as only 6 years old and sales of good act.

Doubt to....loads of problems with the silica bag in the coolant expansion tank splitting & those beads getting into the heater matrix & blocking it...& it takes at least 3yrs for that happen..
 

jimlloyd40

Autocross Champion
Location
Phoenix
Car(s)
2018 SE DSG
Doubt to....loads of problems with the silica bag in the coolant expansion tank splitting & those beads getting into the heater matrix & blocking it...& it takes at least 3yrs for that happen..

Is that true for newer cars starting with the 18 models? If it is it sounds like a good reason to remove the bag.
 

golfdave

Autocross Champion
Location
Scotland (U.K.)
Car(s)
Mk7 Golf GT Estate
Is that true for newer cars starting with the 18 models? If it is it sounds like a good reason to remove the bag.

Yes, I saw a Jan 2019 MK7.5 GTI PP with the silica bag yesterday & a very concerned owner....!!!
 

golfdave

Autocross Champion
Location
Scotland (U.K.)
Car(s)
Mk7 Golf GT Estate
Is there any reason to not remove it?

nope....once the silica bag has been removed you might have to go back to the old way of changing the coolant every 5yrs....
 

SRGTD

Go Kart Champion
Location
UK
I think I may remove mine if I have one. Seems the op has a nightmare On his hands, hopefully he gets it sorted
I seem to remember your car is pretty new, so assume it’s still covered by VW’s 3 year new car warranty. In your position, if you do have one of these silica bags in the cooling system expansion tank, I’d leave it there while the car’s still under warranty - if it splits or bursts during the warranty period, it’ll be VW’s problem, not yours.
 

SRGTD

Go Kart Champion
Location
UK
What does this bag actually do?

I'f i'm not mistaken it's supposed to keep teh antifreeze supplied with silica which will normally break down over time. So instead of changing coolant every x amount of years this will prolong it

Yes, that’s correct.

The silica bag is currently being discussed on golfgtiforum.co.uk and seatcupra.net. This has just been posted on the Seat forum;

From VW's Self Study Program 514 page 31:

"Coolant Expansion Tank with Silicate Repository

The coolant expansion tank contains a silicate repository. Silicate is used to protect the aluminum components in the coolant
system from corrosion. There are silicates in the G13 coolant, but they are used up over time if the engine is subject to high
thermal loads.

To compensate for the silicate consumption, silicate is taken from the repository and added to the coolant. The silicate
repository provides additional protection against corrosion for the aluminum components in the coolant system over the entire
lifespan of the engine."
 

Mikeyd1

Ready to race!
Location
Essex (uk)
I seem to remember your car is pretty new, so assume it’s still covered by VW’s 3 year new car warranty. In your position, if you do have one of these silica bags in the cooling system expansion tank, I’d leave it there while the car’s still under warranty - if it splits or bursts during the warranty period, it’ll be VW’s problem, not yours.
Yep I’ll take tour advice on that one?
 
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