what colour should the coolant be?

[Gavv8]

Is there a genuine technical reason for this or just because VW want you to buy their own brand.

Yes, the blue stuff can overtime eat into the alloy and cause issues.

Not quite right.
In laymen's terms colours are the same basic fluid, blue and green use different inhibition to Red. Red is long life 5/6 years 100k miles that sort of range where blue is two years.
Its when the inhibitors break down that you get cathodic/granular corrosion in Ali and rust in ferrous engines.

Never mix blue/green/red as the inhibition and other additives are not compatible and will make it useless

Ok i'll replace it with G12 at the next change but the blue in mine is only a year old so i'm not bothering with it just yet.

[VW BUSH]

Is there a genuine technical reason for this or just because VW want you to buy their own brand.

Yes, the blue stuff can overtime eat into the alloy and cause issues.

Not quite right.
In laymen's terms colours are the same basic fluid, blue and green use different inhibition to Red. Red is long life 5/6 years 100k miles that sort of range where blue is two years.
Its when the inhibitors break down that you get cathodic/granular corrosion in Ali and rust in ferrous engines.

Never mix blue/green/red as the inhibition and other additives are not compatible and will make it useless

Ok i'll replace it with G12 at the next change but the blue in mine is only a year old so i'm not bothering with it just yet.

If its still blue and clean then it will be fine for now

[Bandit127]

If its still blue and clean then it will be fine for now

Yeah, but when it goes cloudy it will be due to particles of suspended aluminium, gaskets and seals.   

After reading this thread I would probably put G12 coolant on the to-do list (if mine had blue) and time it with a job like a cambelt change.

Luckily mine is pink though - and my list is long enough as it is...

[Khare]

Wow I wasn't aware that off the shelf coolants were so bad. Will deffo use G12 pink from now on.

[VW BUSH]

Wow I wasn't aware that off the shelf coolants were so bad. Will deffo use G12 pink from now on.

They are not bad if they comply with BS 6580 (1992)

[Gavv8]

If its still blue and clean then it will be fine for now

Yeah, but when it goes cloudy it will be due to particles of suspended aluminium, gaskets and seals.   

After reading this thread I would probably put G12 coolant on the to-do list (if mine had blue) and time it with a job like a cambelt change.

Luckily mine is pink though - and my list is long enough as it is...

Pure scaremongering.

[GTIANNIVERSARY16V]

I had a leak.... Ive been topping up with all kindsa sh!t.
Ive got a 1.5 litre G12 bottle now, will that be enough to fill once i drain?

[mrsaunders]

Last time I done mine it drank 7litres

[GTIANNIVERSARY16V]

No way?? I gotta buy 4 more bottles of g12? To inevitably have a leak anyway??

[kahunajb]

You dilute it 50/50 with water however as it is summer I would just use water until your leak is fixed however don't leave it too long as it is also a rust inhibitor.