How do I use Frost Stay Cool?

The mixture content of the Frost Stay Cool should be between 2 and 4%. Below 2% will not give the protection you require. Above 4% can start to give adverse effects, if used in much higher concentrations it can actually promote corrosion.

Difficult to advise on useful life as it depends on the present condition of the cooling system/engine and the length of time the car is used.

Would recommend for maximum protection that it be changed each Autumn in an older car but in a modern car it could be left for two or three years.