Because motor oil does not crystallise or become solid at any temperature, it does not technically freeze. However, at freezing temperatures, motor oil begins to thicken, losing the viscosity that permits it to move throughout the engine and lubricate it. This raises the possibility of engine component damage in cold temperatures.
Since oil is a petroleum product, it does not freeze solid at low temperatures, albeit it loses its liquid properties as the temperature drops. For instance, diesel oil chilled to 0 degrees Fahrenheit will change colour and texture, turning white and so solid that it will no longer flow through the engine. This transformation is due to the precipitation of dissolved waxes in the oil. Because gasoline does not contain these waxes, it is less susceptible to low temperatures than motor oils derived from petroleum.
Choose a light, winter-grade motor oil during the colder months to minimise engine problems caused by thicker oil. Lighter oils flow more smoothly in cold temperatures, whereas heavier oils may have difficulty moving through the engine and potentially prevent the vehicle from starting in the winter. The viscosity of the oil is specified on the bottle’s label. In the title of motor oils that are ideal for winter driving, the letter W appears.
Mobil India, a maker of motor oil, reports that synthetic oil is resistant to thickening in temperatures as cold as -40 degrees Celsius. Conversely, as crude oil cools, it will become extremely viscous and tar-like.