Morning all, I was out having a quick clean up under the bonnet the other day and noticed the coolant sat just over the min mark. Not an issue for me as it was pretty cold, is usually around the max when hot and the car is running fine (water temp and heaters).

Thought I had a bottle of G12 Evo kicking about, so I dug it out however I’ve found that there is a noticeable difference in colour between what’s in the expansion tank and the bottle.

The coolant looks clean and clear with no signs of oil contamination. Dipstick looks good too. The car is a MY20 2.0 TSI with just over 40k miles on the clock. Full main dealer service history. Had the car for around 18 months.

Is this a cause for concern or is it simply a case of replacing the coolant as it’s probably the same stuff from build and is 5 years old?

Edited 22 April, 20251 yr by CookieMonster87

Good afternoon CM. Most likely the original coolant has simply become diluted over time - has it ever been just topped up with plain water?

Probably due for a coolant change anyway.

Whilst you are there, can you confirm whether the silica teabag is removed or not? If you have a single skinned coolant header tank, remove it as it will split on you otherwise.

Skoda recommend coolant change every 5 years, so I recommend you get this done.

@Warrior193 @varaderoguy evening both. Many thanks for your replies.

I’ve certainly never topped it up with water since I’ve taken ownership. Can’t comment on what the dealer may have done whilst in with them for a service mind. If I were to top it up I’d only ever use the G12 Evo.

Contacted the main dealer ref a price on draining and filling. Came out at around £170 noting that this wouldn’t be a flush which I gather involves a lot more work.

I was advised that if the coolant has started to discolour then it is likely to reoccur as a result of “sediment”. First I’ve heard of this outside of the silica bag splitting however there are no signs of this. I don’t believe mine has the silica bag, I have had a good look. Did they not do away with these by MY20 cars?

No need to worry about a full flush - IIRC Skoda will charge just over a grand for that job, which really isn't needed! Sediment sounds like a result of the coolant being used as coolant - over time, rust and stuff can build up in the coolant system and cause the change in colour. I wouldn't worry about it, unless it comes out brown.

Re the silica bag - it should say "mit silikat" on it if yours has the silica bag. My understanding was that G13 cars had the silica bag, whereas G12 Evo didn't? Someone here will know more. I keep meaning to check mine but keep forgetting.

10 hours ago, CookieMonster87 said:

@Warrior193 @varaderoguy evening both. Many thanks for your replies.

I’ve certainly never topped it up with water since I’ve taken ownership. Can’t comment on what the dealer may have done whilst in with them for a service mind. If I were to top it up I’d only ever use the G12 Evo.

Contacted the main dealer ref a price on draining and filling. Came out at around £170 noting that this wouldn’t be a flush which I gather involves a lot more work.

I was advised that if the coolant has started to discolour then it is likely to reoccur as a result of “sediment”. First I’ve heard of this outside of the silica bag splitting however there are no signs of this. I don’t believe mine has the silica bag, I have had a good look. Did they not do away with these by MY20 cars?

I'd recommend asking an independent specialist for a price for the coolant drain/refill.

Definitely doesn't need flushing, but if you are insistent on this, draining the header tank and radiator via the tap on the bottom of the radiator then using a couple of litres of de-minerialised water to get rid of any sediment is appropriate. Then refill with G12evo.

12 hours ago, CookieMonster87 said:

@Warrior193 @varaderoguy evening both. Many thanks for your replies.

I’ve certainly never topped it up with water since I’ve taken ownership. Can’t comment on what the dealer may have done whilst in with them for a service mind. If I were to top it up I’d only ever use the G12 Evo.

Contacted the main dealer ref a price on draining and filling. Came out at around £170 noting that this wouldn’t be a flush which I gather involves a lot more work.

I was advised that if the coolant has started to discolour then it is likely to reoccur as a result of “sediment”. First I’ve heard of this outside of the silica bag splitting however there are no signs of this. I don’t believe mine has the silica bag, I have had a good look. Did they not do away with these by MY20 cars?

Umm... nope. I found one in my MY19 build car and I've removed a couple of silica teabags from header tanks on MY20 and 21 cars. They are still there.

1 hour ago, varaderoguy said:

Umm... nope. I found one in my MY19 build car and I've removed a couple of silica teabags from header tanks on MY20 and 21 cars. They are still there.

Is this on cars with G12 Evo? I’ve been lied to!

23 hours ago, OccyVRS said:

Is this on cars with G12 Evo? I’ve been lied to!

Yes, this is cars with G12Evo.

A quick update on this. Booked the car in at a reputable indy for a coolant change and a check of the expansion tank for the silica bag.

I was quoted around £170 which included the replacement of the expansion tank if it was found to contain the silica bag.

Received a phone call a couple of hours after dropping off to say that they had done a test of the coolant and found that it’s well within the operating range. In addition they said there was no silica bag present (MY20 car) or any signs of contaminants in the coolant. I was advised that there was no need to replace the coolant and it’d be a waste of money although they were still happy to proceed if I wanted.

I chose not to go ahead as, bar the noticeable colour difference, there is no evidence to warrant the change.

All the fluid levels are checked regularly so I’ll follow up if there are any significant changes.

On 22/04/2025 at 22:26, CookieMonster87 said:

reputable indy

On 22/04/2025 at 22:26, CookieMonster87 said:

I was advised that there was no need to replace the coolant and it’d be a waste of money

Good to know there are still some honest garages around.