Please note one thing....typical coolent solutions available in the market are already pre-mixed...they need not to be further diluted unless the pre-mix ratio stipulated on the bottles differs from what you want to achieve in your circuit...Caltex coolant is, i think, a CONCENTRATE...not pre-mixed....
Secondly, santro manual says 40% Coolent (concentrate) 60% salt free water for tropical areas (50-50 for cold climate areas) ....please keep in mind that its water that takes off most of the heat...the main function of coolent is to act as a corrosion inhibitor under a high temp environment.....increasing coolent proportion reduces heat exchanging properties of your cooling circuit...
Thirdly, the ingredients of ethylene glycol based systems are ususally eaten up during the course of time ...in order to maintain the proper specific gravity (i-e coolent-water ratio) you need to periodically replenish it by topping up with concentrates/pre-mixed solutions....unless the coolent you are using is specifically a LONG LIFE COOLENT like Caltex or Toyota...
In the end, its not about 70% or 60%...these are not magical numbers that can do wonders to your cooling system....simply KNOW what you are doing...and dont believe in myths and wrong theories....
