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Model specific boards => Golf mk2 => Topic started by: Lukechamp83 on 17 April 2012, 16:29
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Firstly sorry if this topic has been covered before! I have searched for the answer but couldn't seem to find it.
My newly purchased 1990 8v doesn't appear to have g12 in it.... It's a blue colour, anyone know what this is?
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Screenwash?
:grin:
A bit of research later....
http://www.blauparts.com/vw/vw_fluid/vw_antifreeze_anti_freeze_fluid.shtml
http://gti-vr6.net/library/engine/blue_or_red_coolant.html#mark4
From The AA-Academy website, some FYI.
The terms G11, G12 and G12+ are classifications of antifreeze developed by the VW Group, made by BASF, but seem to have gained universal acceptance.
The traditional antifreezes are generally classed as G11 – usually blue, green or yellow. These contain phosphate, nitrate, nitrite and silicate-based additives. They are used in a base of mono-ethylene glycol which is the toxic stuff.
Mono-ethylene glycol (MEG) has a density of 1.110 and registers on a standard issue tester/hydrometer. It is also the basis for many of the OAT antifreezes which vary in colour from florescent yellow to red, and are classed as G12. BUT Toyota use a red non-OAT antifreeze and the MG Rover SV uses green/yellow OAT – so you certainly can’t rely on the colour to tell you which sort of antifreeze is being used in a particular engine. Japanese antifreeze is phosphate based with an OAT package.
Silicate levels in G11 antifreezes vary. The level used to be as high as 1000 ppm, but this has been reduced to around 250 ppm. At this level there shouldn’t be any precipitation of silicates if mixed with another type of antifreeze. You may have heard of, or seen, cases of horrible green/yellow gel/sludge in the radiator if different types of antifreeze are mixed. BMW still favour a conventional high silicone green anti-freeze.
G12+ is another OAT based antifreeze, purple in colour, but this can be mixed with G11 or G12 without causing any problems.
Antifreezes needed to become less toxic and mono-propylene glycol (MPG) is now used by some car manufacturers, such as Fiat – and it’s compulsory in Switzerland, mixed with the G12 or G12+ additive package. MPG has a density of 1.033 and although it might register on your ordinary antifreeze tester, the figures won’t be right. Accurate measurement needs a refractometer.
MPG and MEG are compatible and mixing won’t cause any problems – in fact they are used together for use in the Arctic.
Most vehicle manufacturers specify a 50:50 mix of water to antifreeze. The principle of an impurity lowering the freezing point is limited. The minimum freezing point achievable by this method is around -50ºC and occurs at 60 or 70 per cent concentration. Above this concentration it will not lower the freezing point further and at 90 per cent antifreeze concentration the solution will begin to freeze at only -20ºC (it doesn’t form proper ice – it’s more like a nasty thick sludge). Corrosion and cavitation prevention need the 50:50 mix.
A combustion gas leak (resulting from head gasket failure) will deplete the corrosion inhibitors as the carbon dioxide dissolves in the coolant and forms carbonic acid.
Now the risk of silicate precipitation has been reduced there is still an issue with different corrosion inhibitor packages which can work against each other.
If you check a car which has an unclear service history, you’ll have no idea what is already in the cooling system. It could have been topped up a dozen times with different antifreezes so to avoid the possibility of production of the gel it is safest to use a G12+ antifreeze such as Comma Extreme Red. This is a very bland/non-reactive mix and shouldn’t cause any problems.
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Yep could be anything so what I always do is take a sample of the old coolant and mix with a small amount of new coolant to make sure nothing forms before I start changing it.
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Thanks mate amazingly in depth answer!! I've actually ended up changing a slightly corroded water hose and drained the old coolant at the same time. Now running g12 :) I don't know why but this makes me happy!
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Thanks mate amazingly in depth copy and paste!! I've actually ended up changing a slightly corroded water hose and drained the old coolant at the same time. Now running g12 :) I don't know why but this makes me happy!
Just rectified your statement for you. :smiley:
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Thanks mate amazingly in depth copy and paste!! I've actually ended up changing a slightly corroded water hose and drained the old coolant at the same time. Now running g12 :) I don't know why but this makes me happy!
Just rectified your statement for you. :smiley:
Typical Yorkshire Humour.... :rolleyes: :laugh: :laugh: :laugh: :laugh:
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Ha! :)
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:tongue: