Glycol/water refrigerant is composed of 45%-36% water.  The fluid mixture can be pink or red to help identify what it is composed of. Normally the glycol will be ethylene glycol mixed with water. This mixture has better thermal transfer capacity than other cooling fluids. Ethylene glycol mixtures are also great lubricants for machines that have high wear rates. Glycol/water mixtures should not be mixed with other water/glycol mixtures due to the different chemical combinations of both mixtures. Different brands may use chemical variations even if two mixtures are considered “water/glycol mix”. It is not recommended to have more than one brand of coolant in a system. Not all glycol/water refrigerants are safe.  Depending upon the amount of glycol in the mixture some glycol/water fluids can with stand lower freezing points. Below is a table marked with freezing points of ethylene glycol/ water mix.



Freezing Points
Ethylene Glycol Solution 60 50 40 30 20 10 0
Percent by Volume
Temperature -52.8 -36.8 -23.5 -13.7 -7.9 -3.4 0
°F -63 -34.2 -10.3 7.3 17.8 25.9 32