Last night I replaced the coolant tank for one without the "mit silikat" statement. I couldn't actually see a silicone bag in the old tank but I have heard that some are double walled and you can't easily see. So for some cheap piece of mind I decided to replaced it.

After installing the new tank and pouring in the contents of the old tank, I noticed some residue left over in the jug I used that looks very silicone like. I'm unsure of how to react to this, the car is now on 98k miles and the previous owner had owned from new looking after the car extremely well. Could I be safe in assuming he had removed the bag himself? Or do you think this has happened as a result of the bag exploding?

The coolant is a nice clean bright pink colour and the old tank showed very little fouling which I suppose is reassuring.

I do have a minor coolant leak, not sure from where but the water pump has not been replaced yet, which is the usual suspect.

I am taking the car on a long 1000+ mile trip this weekend and need to avoid any car troubles. Is this amount of residue worth worrying about? is there anything I can check? Just looking for any sort of advice right now.

Thanks in advance,

Matt

Unfortunately I cannot see the images that you uploaded, however my experience is that the bags are pretty robust, I have removed a few from expansion tanks and never had one split (but I am aware that they can degrade over time).

There is often some small amounts of residue in the expansion tank and if you have not had any issues to date and have replaced the expansion tank I would not expect you to suddenly have issues.

One thing that I will add, if you are keeping this car for "a while", if it still has G13 coolant in it, it should get replaced with G12 EVO as it was only G13 that needed the Silicate pouches to add Silicate back into the coolant as it was being depleted in use, especially with certain engines/temperatures. G12 EVO does not need this which is why "Mit Silikat" has disappeared from newer VAG car reservoirs.

Some people will say that it's easy to work out which coolant is in the system by checking its colour - I can't say that I'm 100% certain that I can/could, I've replaced the G13 with G12 EVO in both our cars - more due to the car's/coolant's age than anything else.

Decoding Volkswagen Coolant Families: From G12 to G13

Volkswagen has evolved its coolants over the decades. Here’s the lineup every owner needs to know.

Classic and Reliable: G12 Coolant

The original long-life red/pink coolant (OAT technology). Nitrate-free, phosphate-free, and silicate-free, G12 was used by the auto manufacturer from the late ’90s to mid-2000s.

• G12 (original red)

• G12+ (improved red/pink)

• G12++ (even longer life)

• G12 EVO (latest violet-ready evolution)

• Ideal for the MK4 Golf, the Beetle, and the early Passat.

The Modern Eco-Warrior: G13 Coolant

Introduced around 2008, G13 swaps some glycol for glycerin (a veggie-derived byproduct), making it more environmentally friendly while still delivering 150,000-mile protection.

• Violet or purple color

• Fully compatible when mixing with G12+, G12++, or G12 EVO

• Slightly different corrosion package, even better for newer aluminum blocks

• Recommended for every Volkswagen from model year 2008 onward (Atlas, Tiguan, newer Golf/Jetta, etc.).

The Universal Champions: G12+, G12++, and G12 EVO

These are the “safe for almost anything” options. Silicate-free, backward-compatible with old G11/G12, and forward-compatible with G13.

• Use them to top off almost any Volkswagen vehicle without drama.

• Built to add long-term rust, frost, and overheating protection.

REAL-WORLD EXAMPLE: A correctly matched G12++ or G13 mix prevents radiator rust, resists freeze damage in winter, and helps the cooling system shed excess heat.

Source/Copyright: Volkswagen USA

That Bright Coolant Warning Light? Don’t Ignore It!

When the red thermometer or “coolant low” icon lights up on your dashboard, pull over safely, shut off the engine, and let it cool for at least 30 minutes before popping the hood.

Hot, pressurised coolant can cause severe burns.

Mixing Coolants and Smart Upgrade Tips

Yes, G13 plays nicely with G12+, G12++, and G12 EVO in a pinch, but always top off with the exact specification for best results.

The following color guide is helpful but isn’t foolproof:

• G11 – blue (ancient, avoid)

• G12/G12+ – red or pink

• G12++/G13 – violet/purple

• Never gamble with off-brand “fits all” coolants; they often contain silicates or phosphates that attack Volkswagen seals and sensors. Stick to genuine Volkswagen G13, G12++, or G12 EVO.