SILICA BAG IS NOT FOR LIFE
▶ A family friend of mine bought a SEAT Ateca. One day the low coolant light came on. Her father takes a look and the coolant tank is full of lumps, so he tops it up and she drives it back to the dealer she bought it from. Turns out SEAT, and looking online, a lot of VAG cars have a silica pouch fitting in the coolant header tank to prolong coolant life.
The cause of the ‘lumps’ is the bag had burst, and the ‘lumps’ are now all throughout the coolant system and worst case blocking the radiator and heater matrix. As the car is five-years-old this is not covered under warranty and she has been hit with a large bill to replace the header tank, remove the radiator and coolant pump and flush the system, hoping the heater matrix is not blocked or that will add another £100 and 3-4 hours labour to an already expensive repair.
I take a keen interest in cars, old and new but this is news to me, and was wondering if you have covered it in the magazine and I have just missed it. Either way, seems to be a bit of a ticking time bomb and feel people should be aware and remove it asap!
Good info on this link www.seatcupra.net/ forums/threads/silica-grain-in-the-headertank.449145/page-9
Barry Morrison
Martyn Knowles replies: Thanks for the information on this Barry. I had meant to inform readers about this last year as I was notified by my local VAG specialists concerning the silica bag location. They have a blog about it here: https://vasstechnik.co.uk/2022/01/26/silica-bag-engine-problems/
The cars affected are made between 2012 and 2019 and if you buy a replacement expansion header tank, the new one arrives without a silica bag included. The silica bag was placed inside the header tank to prolong the life of the coolant but, if the bag splits – usually after the manufacturer warranty has expired – it will send silica crystals in to your cooling system. Not good!
If you own a petrol or diesel Audi, SEAT, Skoda or Volkswagen I advise you take action to check for a silica bag – and remove it if found. Or purchase a new header tank as they are cheap enough.