Editing Coolant (section)

===Mixing===
It is generally recommended not to mix different coolants even if they are the same colour, although more modern types are increasingly becoming safe to mix with anything.

The "classic" IAT coolants (eg. G11) should never be mixed with the first-generation "plain" OAT coolants (eg. G12).  OAT coolants were then improved (ie. G12+, G30, etc) so that they could be safely mixed with older IAT coolants and the original OAT coolants, albeit potentially with some loss of protection length.  These were further developed to Si-OAT and PSi-OAT coolants, which are also generally safe to mix with most older coolants.  Mixing coolants of radically different colours may produce an unpleasant-looking brown result.

HOAT, PHOAT, etc., may not be compatible with other types, and there are many coolants that don't fit cleanly into any of these categories.  Again the safest advice is never to mix different types.

Although VW G13 and other coolants containing glycerol contain a different combination of antifreezes, it is usually safe to mix them with any other type.