Firstly, don't be fooled by the colours; there is no universal colouring scheme for engine coolant. Different brands use different colours - blue, green, red, yellow, orange and pink. For example Yamalube was red when I bought my bike in 2008, but now the same stuff (made by Motul and called MotoCool) is yellow/orange.

The XT660 cooling system requires an ethylene glycol based coolant without silicate, phosphate or boric corrosion inhibitors. This type of coolant is often branded as "organic" and falls into the OAT (organic acid technology) category. Whichever brand you choose look for one that says "OAT" or "organic" on the label and is ethylene glycol based. They often say they are silicate and boric free. You should be able to get it at Halfords as OAT is the most common type of motorcycle coolant.

It is not recommended to mix IAT (inorganic acid technology), or HOAT (hybird organic acid technology) coolants with OAT types because they contain silicates, phosphates and boric acid which effect the life of the coolant and can cause deposits to build up.

As a precaution, it is always best to flush the cooling system through with clean water before replacing the coolant.

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