Really cannot see the point or benefit of this.
Your cooling system should not be operating at over 100℃.
If your water is vaporising within the cooling system then there is a problem with the system. These systems were designed with water cooling in mind as water has a very good thermal conductivity, much better than any oil based liquids. The use of certain steels and aluminiums within the block also help to dissipate heat quickly where needed most.
Oil based liquids have far higher boiling points but that is about all they offer. They will infact retain so much more heat aswell as taking longer to reach a suitable operating temperature and cooling down after the vehicle is switched off.
And as mentioned no water coolant should ever boil in a well designed and properly operating water cooling system anyway so the higher boiling point that these coolants offer really isn't a benefit anyway.