ASTM D1177 – Freezing Point of Aqueous Engine Coolants
Engine coolants are typically aqueous glycol solutions formulated to protect the engines from thermal damage during normal operation. Idle engines in very cold environments risk coolant freezing, putting engines at risk in two ways: (1) Upon start up, the coolant will not offer adequate protection, (2) Coolant expansion during freezing may damage hoses and other system components. The freezing point of coolants is determined in this test.
The sample is placed in a cooling tube fitted with a temperature measuring device and a spiral stirring rod. The temperature is lowered and recorded at regular intervals while the sample is thoroughly agitated. The temperature versus time graph is generated and the freezing point is determined by the deflection on the curve. This freezing point is reported in ºC.