I have used OAT Long life coolant in my motorbikes and Honda engines for many years, it is silicate free - the ethylene glycol is the actual anti freeze bit and the OAT is the anti corrosion package (which is the bit that makes modern coolant last 10 years before change) the ethylene glycol does not really lose its efficiency, it is the anti corrosion that gets depleted. Funny thing about coolant, 50% dilution gives best protection from freezing, too little OR TOO MUCH will raise freezing point. Colour of coolant does not mean much as it is only there to show any leaks.