Anti freeze - mixing

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Wed 28 Dec 2005 21:52
Anti freeze - mixing - islandman
Am I right in assuming it,s ok to mix anti-freeze of different colours as long as they are both the same type -- ie Ethylene Glycol.
Hope you,ve all had a good xmas!
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Wed 28 Dec 2005 22:03
Anti freeze - mixing - Hamsafar
No, they have incompatible additives.
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Wed 28 Dec 2005 23:49
Anti freeze - mixing - Ian D
Mixing different colour antifreezes - big no no

see www.honestjohn.co.uk/forum/post/index.htm?t=35193&...f
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Thu 29 Dec 2005 10:08
Anti freeze - mixing - defender
we use about 75 litres of anti freeze a year sometimes blue sometimes green depending what my local supplier has with no problems over the last 20 years
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Thu 29 Dec 2005 11:05
Anti freeze - mixing - Aprilia
The colour is just due to a dye. The 'raw' antifreeze mixture is almost colourless. Colour therefore doesn't tell you much about the constituent chemicals.

Almost all antifreeze is Mono Ethylene Glycol-based (methanol and poly ethylene glycols are not much used). Methanol is highly flammable and PEG is not a great heat conductor.

The major difference is in the anti-corrosion additives; silicates, phosphates and organic acids (OAT) are used. You need to match these up. If you really don't know what's in there then give a good flush and refill with the vehicle manufacturers own antifreeze.
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